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PROJECTS 8×8 LED Matrix MAX7219 Tutorial with Scrolling Text & Android Control via Bluetooth ​ Read More Interfacing GPS with Arduino (Neo-6M-001) In this tutorial we will learn how to use a GPS Module with Arduino. Neo 6M (Ublox NEO6MV2) is a I2C compliant GPS module. This post discusses details on wiring Ublox Neo 6M with Arduino or an USB to Serial/TTL adapter, basic interactions with module using serial communication, using u -center GUI in visualizations, as well as using TinyGPS library to extract fine grained results from the module output. Read More Analog Joystick Interfacing with Arduino UNO. In this tutorial we will learn how to interface an Analog Joystick with the Arduino Uno and checking the values on the Serial Monitor. Read More Interfacing of MQ2 (gas) sensor with Arduino Uno. In this tutorial we will learn how to interface a MQ2 (gas) Sensor with the Arduino Uno Read More Interfacing of LDR Sensor Module with Arduino Uno. In this tutorial we will learn how to interface a LDR sensor Module with the Arduino Uno. Read More Interfacing of RFID Module with Arduino Uno. In this tutorial we will learn how to interface a RFID module with the Arduino Uno. Read More Measuring Distance using Ultrasonic Sensor with Arduino In this project we will learn the basics of how to measure distance using an ultrasonic sensor with an Arduino, which further can be used for controlling other parameters of a robot or many other applications. Read More Measuring Humidity and temperature using DHT11 sensor with Arduino. In this tutorial, we will learn how to use a DHT (DHT11 version) Temperature and Humidity Sensor. It’s accurate enough for most projects that need to keep track of humidity and temperature readings. We will be using a Library specifically designed for these sensors that will make our code short and easy to write. Read More 4*4 Keypad Interfacing with Arduino UNO. In this tutorial, we will learn how to interface a 4*4 Keypad with the Arduino Uno and check the values on the Serial Monitor. Read More Interfacing of Touch Sensor with Arduino Uno. In this tutorial, we will learn how to interface a Touch Sensor with the Arduino Uno. Read More Interfacing of Pulse Rate Sensor with Arduino Uno. In this tutorial we will learn how to interface a Pulse Rate Sensor with the Arduino Uno. Read More Finding an obstacle using IR Sensor with Arduino In this project we will learn the basics of how to find for an obstacle using an Infrared sensor with an Arduino, which further can be used for controlling other parameters of a robot and many other applications too. Read More Interfacing of Force Pressure Sensor with Arduino Uno. In this tutorial we will learn how to interface a Force Pressure Sensor with the Arduino Uno. Read More Displaying a text message on LCD Display using 16X2 Segment Display with Arduino. : In this tutorial we will learn how to interface a 16×2 LCD (liquid crystal display) with the Arduino Uno. Read More Interfacing of Metal Touch Sensor with Arduino. In this tutorial we will learn how to interface a Metal Touch Sensor with the Arduino Read More Interfacing with MQ-3 Alcohol Sensor Module ​ Read More Interfacing of 28BYJ Stepper Driver with Arduino. In this tutorial we will learn how to interface a Flex Sensor with the Arduino Uno. Read More Interfacing of Buzzer with Arduino Uno. In this tutorial, we will learn how to interface a Buzzer with the Arduino Uno. Read More Interfacing of 4 Digit Segment Display with Arduino Uno. In this tutorial, we will learn how to interface a 4-digit segment display with the Arduino Uno. Read More Interfacing 2 Channel Relay Module with Arduino and control High Voltage AC (current). In this tutorial, we will learn how to interface a 2 channel relay module with the Arduino Uno. Read More Measuring water flow rate and calculating quantity using Flow Sensor with Arduino. In this tutorial, we will learn how to use a water flow sensor with Arduino. We will use the serial monitor for printing the water flow rate in liters per hour and the total of liters flowing since starting. So, let's get started! Read More Interfacing of GSM 800 L Modules with Arduino. In this tutorial we will learn how to interface GSM 800L Module with the Arduino Uno. Read More Bluetooth Controlled Car Using Arduino Uno. This project shows how you can build a car which can be controlled by your Smartphone using an android application via Bluetooth. Read More Interfacing of Laser Diode with Arduino Uno. In this tutorial we will learn how to interface a Laser Diode with the Arduino Uno. Read More Interfacing of Temperature Sensor (LM35) with Arduino Uno. In this tutorial we will learn how to interface a Temperature Sensor with the Arduino Uno. Read More Motion Detection using PIR Sensor with Arduino In this Arduino Tutorial we will learn how a PIR Sensor works and how to use it with the Arduino Board for detecting motion. Read More Interfacing of Sound sensor with Arduino Uno. In this tutorial we will learn how to interface a Sound Sensor with the Arduino Uno. Read More Interfacing Colour Sensor with Arduino (TCS3200) : In this tutorial, we will learn how to use a colour sensor with Arduino. We will use the serial monitor for printing the colour values. So let's get started! This sensor is used for detecting primary colours (red, green and blue, or RGB)—colours that are physically available in LEDs in one package; for example, common cathode or common-cathode RGB LED. We can display primary colours and also generate specific colours by modifying the Arduino code. Read More Character Displaying using 8X8 LED Matrix MAX7219 with Arduino Uno In this Arduino project we will learn how to control 8×8 LED Matrix using the MAX7219 driver and the Arduino board. Read More Measuring soil moisture using Soil Moisture Sensor with Arduino (Y-38) In this tutorial, we will learn how to read soil moisture data using Analog Soil Moisture Sensor on the Arduino Platform. We are reading data from Analog Moisture Sensor, so we will get readings in the range 0 to 1023. Lesser the value means lesser the moisture in the soil. Read More Interfacing of Rain Drop Sensor with Arduino Uno. In this tutorial we will learn how to interface a Rain Drop Sensor with the Arduino Uno. Read More

Back Bluetooth Controlled Car Using Arduino Uno. Material Required: Material Quantity Arduino Uno 1 12V DC Motor /BO motor 2 Jumper cables 15 HC-05 Bluetooth Module 1 Breadboard 1 Breadboard 1 This tutorial will teach you how to create your own Bluetooth controlled car. So let’s get started. This will be a Bluetooth controlled car so for this project we will be using HC-05 Bluetooth module to receive the controlling data packets. We will also need an android app which will be sending the controlling data packets to the Bluetooth module. We will use a third party application ( https://play.google.com/store/apps/details?id=com.broxcode.arduinobluetoothfree&hl=en to download) for this purpose. Let's build the hardware (Body of the car) The car which we are building for this project will be a dual motor car. Two 12 v 200 rpm DC or BO motors. You can use a readymade chassis. Circuit Now let us build the circuit. CODE : Here we will use the direction of rotation of motors to control the direction of the car. Forward - Both motors move in forward direction. Backward - Both motors move in backward direction. Left - Left motor moves backwards and right motor moves forward. Right - Left motor moves forwards and right motor moves backward. Stop - Both motors stop Tested Programming Code: #include AF_DCMotor motor1(1); //motor1 is the left motor AF_DCMotor motor2(2); //motor2 is the right motor int val; void setup() { Serial.begin(9600); motor1.setSpeed(255); //motor speed is set motor2.setSpeed(255); Stop(); } void loop() { bt=Serial.read(); if(val=='1') //when the bluetooth module recieves 1 the car moves forward { forward(); } if(val=='2') //when the bluetooth module recieves 2 the car moves backward { backward(); } if(val=='3') //when the bluetooth module recieves 3 the car moves left { left(); } if(val=='4') //when the bluetooth module recieves 4 the car moves right { right(); } if(val=='5') //when the bluetooth module recieves 5 the car stops { Stop(); } } void forward() { motor1.run(FORWARD); motor2.run(FORWARD); } void backward() { motor1.run(BACKWARD); motor2.run(BACKWARD); } void left() { motor1.run(BACKWARD); motor2.run(FORWARD); } void right() { motor1.run(FORWARD); motor2.run(BACKWARD); } void Stop() { motor1.run(RELEASE); motor2.run(RELEASE); } Precautions: 1. Double check the connections before powering on the circuit. 2. Don’t use loose jumper cables. 3. Check whether proper board is selected from Arduino IDE. 4. Ensure proper placement of Bluetooth and Motor driver for correct working. 5. Don’t lose hope if it does not run properly for the first time, try again. Reference URL GET IN TOUCH We'd love to hear from you Contact Us

Back Interfacing of Pulse Rate Sensor with Arduino Uno. What is a Pulse Rate Sensor? The pulse sensor we are going to use is a plug and play heart rate sensor. This sensor is quite easy to use and operate. Place your finger on top of the sensor and it will sense the heartbeat by measuring the change in light from the expansion of capillary blood vessels. The pulse sensor module has a light which helps in measuring the pulse rate. When we place the finger on the pulse sensor, the light reflected will change based on the volume of blood inside the capillary blood vessels. Material Required: Material Quantity Arduino Uno 1 Pulse Rate Sensor 1 Jumper cables 6 LED 1 Pinout Diagram: Circuit Diagram: Connect the pulse sensor with Arduino as follows: GND pin of pulse sensor to GND of Arduino VCC of pulse sensor to 5V of Arduino A0 of pulse sensor to A0 of Arduino After that, connect the LED to pin 13 and GND of Arduino as shown in the figure below. Tested Programming Code: int PulseSensorPurplePin = 0; int LED13 = 13; int Signal; int Threshold = 550; void setup() { pinMode(LED13,OUTPUT); Serial.begin(9600); } void loop() { Signal = analogRead(PulseSensorPurplePin); Serial.println(Signal); if(Signal > Threshold){ digitalWrite(LED13,HIGH); } else { digitalWrite(LED13,LOW); } delay(10); } Precautions: Double check the connections before powering on the circuit. Don’t use loose jumper cables. Check whether proper board is selected from Arduino IDE. Ensure proper placement of pulse rate Sensor for correct working. Don’t lose hope if pulse rate Sensor does not run properly for the first time, try again. Conclusion: Once your sketch is running, you have to open your serial monitor. There you can see the Pulse Rate (BPM) on the sensor. Reference URL GET IN TOUCH We'd love to hear from you Contact Us

Back Interfacing Colour Sensor with Arduino (TCS3200) What is a Color Sensor? A colour sensor can determine different colours. They will utilize a means of emitting light and then look at the reflected light to determine an object’s colour. This will give the machine the actual colour of that object. These sensors are in use in quite a few different applications today. You can find them in quality control systems, packaging systems, and more. Specifications: · Power: 2.7V to 5.5V · Size: 28.4 x 28.4mm (1.12 x 1.12″) · Interface: digital TTL · High-resolution conversion of light intensity to frequency · Programmable colour and full-scale output frequency · Communicates directly to the microcontroller Material Required: Material Quantity Arduino Uno 1 Colour Sensor 1 Jumper cables 10 Pinout Diagram: Working: The TCS230 senses colour light with the help of an 8 x 8 array of photodiodes. Then using a Current-to-Frequency Converter the readings from the photodiodes are converted into a square wave with a frequency directly proportional to the light intensity. Finally, using the Arduino Board we can read the square wave output and get the results for the colour. If we take a closer look at the sensor we can see how it detects various colours. The photodiodes have three different colour filters. Sixteen of them have red filters, another 16 have green filters, another 16 have blue filters and the other 16 photodiodes are clear with no filters. Every 16 photodiodes are connected in parallel, so using the two control pins S2 and S3 we can select which of them will be read. So for example, if we want to detect red colour, we can just use the 16 red filtered photodiodes by setting the two pins to a low logic level according to the table. The sensor has two more control pins, S0 and S1 which are used for scaling the output frequency. The frequency can be scaled to three different preset values of 100 %, 20 % or 2%. This frequency-scaling function allows the output of the sensor to be optimized for various frequency counters or microcontrollers. Circuit Diagram: Tested Programming Code: First, we need to define the pins to which the sensor is connected and define a variable for reading the frequency. In the setup section, we need to define the four control pins as outputs and the sensor output as an Arduino input. Here we also need to set the frequency scaling, for this example, I will set it to 20%, and start the serial communication for displaying the results in the Serial Monitor. In the loop section, we will start with reading the red filtered photodiodes. For that purpose, we will set the two control pins S2 and S3 to low logic level. Then using the “pulseIn()” function we will read the output frequency and put it into the variable “frequency”. Using the Serial.print() function we will print the result on the serial monitor. The same procedure goes for the two other colours, we just need to adjust the control pins for the appropriate colour. Code: #define S0 4 #define S1 5 #define S2 6 #define S3 7 #define sensorOut 8 int frequency = 0; void setup() { pinMode(S0, OUTPUT); pinMode(S1, OUTPUT); pinMode(S2, OUTPUT); pinMode(S3, OUTPUT); pinMode(sensorOut, INPUT); digitalWrite(S0,HIGH); digitalWrite(S1,LOW); Serial.begin(9600);} void loop() { digitalWrite(S2,LOW); digitalWrite(S3,LOW); frequency = pulseIn(sensorOut, LOW); Serial.print("R= ");//printing name Serial.print(frequency);//printing RED color frequency Serial.print(" "); delay(100); digitalWrite(S2,HIGH); digitalWrite(S3,HIGH); frequency = pulseIn(sensorOut, LOW); Serial.print("G= "); Serial.print(frequency);Serial.print(" "); delay(100); digitalWrite(S2,LOW); digitalWrite(S3,HIGH);frequency pulseIn(sensorOut, LOW); Serial.print("B= ");//printing name Serial.print(frequency);//printing RED color frequency Serial.println(" "); delay(100); } Precautions: 1. Double-check the connections before powering on the circuit. 2. Don’t use loose jumper cables. 3. Check whether the proper board is selected from Arduino IDE. 4. Ensure proper placement of sensor for correct working. 5. Try it with different colours and see the change in values. Conclusion: You can successfully identify different colours using this sensor and can be deployed for many other purposes like item sorting, Rubiks cube solving etc. Output: Situation Screenshot: Serial Monitor (Ctrl+Shift+M) BLUE : GREEN : RED Reference URL GET IN TOUCH We'd love to hear from you Contact Us

Back 8×8 LED Matrix MAX7219 Tutorial with Scrolling Text & Android Control via Bluetooth Students now you know everything about how a matrix works, let’s move to some advanced part of it. 8×8 LED Matrix Scrolling Arduino Code Next let’s take a look at the scrolling text example and see what’s different. Below the code you will find its description. #include #include PROGMEM const unsigned char CH[] = { 3, 8, B00000000, B00000000, B00000000, B00000000, B00000000, // space 1, 8, B01011111, B00000000, B00000000, B00000000, B00000000, // ! 3, 8, B00000011, B00000000, B00000011, B00000000, B00000000, // " 5, 8, B00010100, B00111110, B00010100, B00111110, B00010100, // # 4, 8, B00100100, B01101010, B00101011, B00010010, B00000000, // $ 5, 8, B01100011, B00010011, B00001000, B01100100, B01100011, // % 5, 8, B00110110, B01001001, B01010110, B00100000, B01010000, // & 1, 8, B00000011, B00000000, B00000000, B00000000, B00000000, // ' 3, 8, B00011100, B00100010, B01000001, B00000000, B00000000, // ( 3, 8, B01000001, B00100010, B00011100, B00000000, B00000000, // ) 5, 8, B00101000, B00011000, B00001110, B00011000, B00101000, //* 5, 8, B00001000, B00001000, B00111110, B00001000, B00001000, // + 2, 8, B10110000, B01110000, B00000000, B00000000, B00000000, // , 4, 8, B00001000, B00001000, B00001000, B00001000, B00000000, // - 2, 8, B01100000, B01100000, B00000000, B00000000, B00000000, // . 4, 8, B01100000, B00011000, B00000110, B00000001, B00000000, // / 4, 8, B00111110, B01000001, B01000001, B00111110, B00000000, // 0 3, 8, B01000010, B01111111, B01000000, B00000000, B00000000, // 1 4, 8, B01100010, B01010001, B01001001, B01000110, B00000000, // 2 4, 8, B00100010, B01000001, B01001001, B00110110, B00000000, // 3 4, 8, B00011000, B00010100, B00010010, B01111111, B00000000, // 4 4, 8, B00100111, B01000101, B01000101, B00111001, B00000000, // 5 4, 8, B00111110, B01001001, B01001001, B00110000, B00000000, // 6 4, 8, B01100001, B00010001, B00001001, B00000111, B00000000, // 7 4, 8, B00110110, B01001001, B01001001, B00110110, B00000000, // 8 4, 8, B00000110, B01001001, B01001001, B00111110, B00000000, // 9 2, 8, B01010000, B00000000, B00000000, B00000000, B00000000, // : 2, 8, B10000000, B01010000, B00000000, B00000000, B00000000, // ; 3, 8, B00010000, B00101000, B01000100, B00000000, B00000000, // < 3, 8, B00010100, B00010100, B00010100, B00000000, B00000000, // = 3, 8, B01000100, B00101000, B00010000, B00000000, B00000000, // > 4, 8, B00000010, B01011001, B00001001, B00000110, B00000000, // ? 5, 8, B00111110, B01001001, B01010101, B01011101, B00001110, // @ 4, 8, B01111110, B00010001, B00010001, B01111110, B00000000, //A 4, 8, B01111111, B01001001, B01001001, B00110110, B00000000, // B 4, 8, B00111110, B01000001, B01000001, B00100010, B00000000, // C 4, 8, B01111111, B01000001, B01000001, B00111110, B00000000, // D 4, 8, B01111111, B01001001, B01001001, B01000001, B00000000, // E 4, 8, B01111111, B00001001, B00001001, B00000001, B00000000, // F 4, 8, B00111110, B01000001, B01001001, B01111010, B00000000, // G 4, 8, B01111111, B00001000, B00001000, B01111111, B00000000, // H 3, 8, B01000001, B01111111, B01000001, B00000000, B00000000, // I 4, 8, B00110000, B01000000, B01000001, B00111111, B00000000, // J 4, 8, B01111111, B00001000, B00010100, B01100011, B00000000, // K 4, 8, B01111111, B01000000, B01000000, B01000000, B00000000, // L 5, 8, B01111111, B00000010, B00001100, B00000010, B01111111, // M 5, 8, B01111111, B00000100, B00001000, B00010000, B01111111, // N 4, 8, B00111110, B01000001, B01000001, B00111110, B00000000, //O 4, 8, B01111111, B00001001, B00001001, B00000110, B00000000, // P 4, 8, B00111110, B01000001, B01000001, B10111110, B00000000, // Q 4, 8, B01111111, B00001001, B00001001, B01110110, B00000000, // R 4, 8, B01000110, B01001001, B01001001, B00110010, B00000000, // S 5, 8, B00000001, B00000001, B01111111, B00000001, B00000001, // T 4, 8, B00111111, B01000000, B01000000, B00111111, B00000000, // U 5, 8, B00001111, B00110000, B01000000, B00110000, B00001111, // V 5, 8, B00111111, B01000000, B00111000, B01000000, B00111111, // W 5, 8, B01100011, B00010100, B00001000, B00010100, B01100011, // X 5, 8, B00000111, B00001000, B01110000, B00001000, B00000111, // Y 4, 8, B01100001, B01010001, B01001001, B01000111, B00000000, // Z 2, 8, B01111111, B01000001, B00000000, B00000000, B00000000, // [ 4, 8, B00000001, B00000110, B00011000, B01100000, B00000000, // \ backslash 2, 8, B01000001, B01111111, B00000000, B00000000, B00000000, // ] 3, 8, B00000010, B00000001, B00000010, B00000000, B00000000, // hat 4, 8, B01000000, B01000000, B01000000, B01000000, B00000000, // _ 2, 8, B00000001, B00000010, B00000000, B00000000, B00000000, // ` 4, 8, B00100000, B01010100, B01010100, B01111000, B00000000, // a 4, 8, B01111111, B01000100, B01000100, B00111000, B00000000, // b 4, 8, B00111000, B01000100, B01000100, B00101000, B00000000, // c 4, 8, B00111000, B01000100, B01000100, B01111111, B00000000, // d 4, 8, B00111000, B01010100, B01010100, B00011000, B00000000, // e 3, 8, B00000100, B01111110, B00000101, B00000000, B00000000, // f 4, 8, B10011000, B10100100, B10100100, B01111000, B00000000, // g 4, 8, B01111111, B00000100, B00000100, B01111000, B00000000, //h 3, 8, B01000100, B01111101, B01000000, B00000000, B00000000, // i 4, 8, B01000000, B10000000, B10000100, B01111101, B00000000, // j 4, 8, B01111111, B00010000, B00101000, B01000100, B00000000, // k 3, 8, B01000001, B01111111, B01000000, B00000000, B00000000, // l 5, 8, B01111100, B00000100, B01111100, B00000100, B01111000, // m 4, 8, B01111100, B00000100, B00000100, B01111000, B00000000, // n 4, 8, B00111000, B01000100, B01000100, B00111000, B00000000, // o 4, 8, B11111100, B00100100, B00100100, B00011000, B00000000, // p 4, 8, B00011000, B00100100, B00100100, B11111100, B00000000, // q 4, 8, B01111100, B00001000, B00000100, B00000100, B00000000, // r 4, 8, B01001000, B01010100, B01010100, B00100100, B00000000, // s 3, 8, B00000100, B00111111, B01000100, B00000000, B00000000, // t 4, 8, B00111100, B01000000, B01000000, B01111100, B00000000, // u 5, 8, B00011100, B00100000, B01000000, B00100000, B00011100, //v 5, 8, B00111100, B01000000, B00111100, B01000000, B00111100, // w 5, 8, B01000100, B00101000, B00010000, B00101000, B01000100, // x 4, 8, B10011100, B10100000, B10100000, B01111100, B00000000, // y 3, 8, B01100100, B01010100, B01001100, B00000000, B00000000, // z 3, 8, B00001000, B00110110, B01000001, B00000000, B00000000, // { 1, 8, B01111111, B00000000, B00000000, B00000000, B00000000, // | 3, 8, B01000001, B00110110, B00001000, B00000000, B00000000, // } 4, 8, B00001000, B00000100, B00001000, B00000100, B00000000, // ~ }; int DIN = 7; // DIN pin of MAX7219 module int CLK = 6; // CLK pin of MAX7219 module int CS = 5; // CS pin of MAX7219 module int maxInUse = 2; MaxMatrix m(DIN, CS, CLK, maxInUse); byte buffer[10]; char text[]= "TechKnowSkola"; // Scrolling text void setup() { m.init(); // module initialize m.setIntensity(15); // dot matix intensity 0-15 } void loop() { printStringWithShift(text, 100); // (text, scrolling speed) } // Display=the extracted characters with scrolling void printCharWithShift(char c, int shift_speed) { if (c < 32) return; c -= 32; memcpy_P(buffer, CH + 7 * c, 7); m.writeSprite(32, 0, buffer); m.setColumn(32 + buffer[0], 0); for (int i = 0; i < buffer[0] + 1; i++) { delay(shift_speed); m.shiftLeft(false, false); } } // Extract the characters from the text string void printStringWithShift(char* s, int shift_speed) { while (*s != 0) { printCharWithShift(*s, shift_speed); s++; } } Now let’s move to the functioning of Bluetooth HC-05 Description: Here we have to include an additional library for the PROGMEN which is variable modifier and it’s used for storing data in the flash memory instead of SRAM. When we have a larger database of variables which are static, like in this case defining letters and characters, it’s better to store them in the flash memory because it’s much bigger, 32K bytes, compared to the 2K bytes of the SRAM. Next with a character array we define the scrolling text and in the loop section the custom function printStringWithShift, prints the scrolling text on the LED matrix with a scrolling speed defined in milliseconds with the second argument. The first thing that this custom function do is that it extracts the characters from the text string and then display these scrolling characters on the led matrix. The particular module that I have can be powered from 3.6 to 6 volts, because it comes on breakout board which contains a voltage regulator. However, the logic voltage level of the data pins is 3.3V. So, the line between the Arduino TX (Transmit Pin, which has 5V output) and the Bluetooth module RX (Receive Pin, which supports only 3.3V) needs to be connected through a voltage divider in order not to burn the module. On the other hand, the line between the Bluetooth module TX pin and the Arduino RX pin can be connected directly because the 3.3V signal from the Bluetooth module is enough to beaccepted as a high logic at the Arduino Board. Circuit Schematics: Here’s how we need to connect the module to the Arduino Board. Connecting the Smartphone to the HC-05 Bluetooth Module and the Arduino Now we are ready to connect the smartphone to the Bluetooth module and the Arduino. What we need to do here is to activate the Bluetooth and the smartphone will find the HC-05 Bluetooth module. Then we need to pair the devices and the default password of the HC-05 module is 1234. After we have paired the devices we need an application for controlling the Arduino. There are many application in the Play Store for this purpose which will work with the Arduino code that we wrote. However, I made my own custom application for this tutorial using the MIT App Inventor online application. This is a great and easy to use application for building Android application and in my next tutorial you can find a detailed step by step guide how to build your own custom Android application for your Arduino Project. Android App for Controlling 8×8 LED Matrix via Bluetooth Once we learned how the MAX7219 works, now we can make the third example which is a practical Arduino project where we will build a custom Android app to control the LED matrix via Bluetooth communication. Before we continue I would suggest you to check detailed tutorials on how to use the HC-05 Bluetooth module and how to build a custom Android app using the MIT App Inventor online application . Here’s the Arduino code and now let’s see the modifications compared to the previous example. /* 8x8 LED Matrix MAX7219 Scrolling Text Android Control via Bluetooth by Dejan Nedelkovsk i, www.HowToMechatronics.com Based on the following library: GitHub | riyas-org/max7219 https://github.com/riyas-org/max7219 */ #include #include #include PROGMEM const unsigned char CH[] = { 3, 8, B00000000, B00000000, B00000000, B00000000, B00000000, // space 1, 8, B01011111, B00000000, B00000000, B00000000, B00000000, // ! 3, 8, B00000011, B00000000, B00000011, B00000000, B00000000, // " 5, 8, B00010100, B00111110, B00010100, B00111110, B00010100, //# 4, 8, B00100100, B01101010, B00101011, B00010010, B00000000, // $ 5, 8, B01100011, B00010011, B00001000, B01100100, B01100011, // % 5, 8, B00110110, B01001001, B01010110, B00100000, B01010000, // & 1, 8, B00000011, B00000000, B00000000, B00000000, B00000000, // ' 3, 8, B00011100, B00100010, B01000001, B00000000, B00000000, // ( 3, 8, B01000001, B00100010, B00011100, B00000000, B00000000, // ) 5, 8, B00101000, B00011000, B00001110, B00011000, B00101000, // * 5, 8, B00001000, B00001000, B00111110, B00001000, B00001000, // + 2, 8, B10110000, B01110000, B00000000, B00000000, B00000000, // , 4, 8, B00001000, B00001000, B00001000, B00001000, B00000000, //- 2, 8, B01100000, B01100000, B00000000, B00000000, B00000000, // . 4, 8, B01100000, B00011000, B00000110, B00000001, B00000000, // / 4, 8, B00111110, B01000001, B01000001, B00111110, B00000000, // 0 3, 8, B01000010, B01111111, B01000000, B00000000, B00000000, // 1 4, 8, B01100010, B01010001, B01001001, B01000110, B00000000, // 2 4, 8, B00100010, B01000001, B01001001, B00110110, B00000000, // 3 4, 8, B00011000, B00010100, B00010010, B01111111, B00000000, // 4 4, 8, B00100111, B01000101, B01000101, B00111001, B00000000, // 5 4, 8, B00111110, B01001001, B01001001, B00110000, B00000000, // 6 4, 8, B01100001, B00010001, B00001001, B00000111, B00000000, // 7 4, 8, B00110110, B01001001, B01001001, B00110110, B00000000, // 8 4, 8, B00000110, B01001001, B01001001, B00111110, B00000000, // 9 2, 8, B01010000, B00000000, B00000000, B00000000, B00000000, // : 2, 8, B10000000, B01010000, B00000000, B00000000, B00000000, //; 3, 8, B00010000, B00101000, B01000100, B00000000, B00000000, // < 3, 8, B00010100, B00010100, B00010100, B00000000, B00000000, // = 3, 8, B01000100, B00101000, B00010000, B00000000, B00000000, // > 4, 8, B00000010, B01011001, B00001001, B00000110, B00000000, // ? 5, 8, B00111110, B01001001, B01010101, B01011101, B00001110, // @ 4, 8, B01111110, B00010001, B00010001, B01111110, B00000000, // A 4, 8, B01111111, B01001001, B01001001, B00110110, B00000000, // B 4, 8, B00111110, B01000001, B01000001, B00100010, B00000000, // C 4, 8, B01111111, B01000001, B01000001, B00111110, B00000000, // D 4, 8, B01111111, B01001001, B01001001, B01000001, B00000000, // E 4, 8, B01111111, B00001001, B00001001, B00000001, B00000000, // F 4, 8, B00111110, B01000001, B01001001, B01111010, B00000000, // G 4, 8, B01111111, B00001000, B00001000, B01111111, B00000000, // H 3, 8, B01000001, B01111111, B01000001, B00000000, B00000000, // I 4, 8, B00110000, B01000000, B01000001, B00111111, B00000000, // J 4, 8, B01111111, B00001000, B00010100, B01100011, B00000000, // K 4, 8, B01111111, B01000000, B01000000, B01000000, B00000000, // L 5, 8, B01111111, B00000010, B00001100, B00000010, B01111111, // M 5, 8, B01111111, B00000100, B00001000, B00010000, B01111111, // N 4, 8, B00111110, B01000001, B01000001, B00111110, B00000000, // O 4, 8, B01111111, B00001001, B00001001, B00000110, B00000000, // P 4, 8, B00111110, B01000001, B01000001, B10111110, B00000000, // Q 4, 8, B01111111, B00001001, B00001001, B01110110, B00000000, // R 4, 8, B01000110, B01001001, B01001001, B00110010, B00000000, // S 5, 8, B00000001, B00000001, B01111111, B00000001, B00000001, //T 4, 8, B00111111, B01000000, B01000000, B00111111, B00000000, // U 5, 8, B00001111, B00110000, B01000000, B00110000, B00001111, // V 5, 8, B00111111, B01000000, B00111000, B01000000, B00111111, // W 5, 8, B01100011, B00010100, B00001000, B00010100, B01100011, // X 5, 8, B00000111, B00001000, B01110000, B00001000, B00000111, // Y 4, 8, B01100001, B01010001, B01001001, B01000111, B00000000, // Z 2, 8, B01111111, B01000001, B00000000, B00000000, B00000000, // [ 4, 8, B00000001, B00000110, B00011000, B01100000, B00000000, // \ backslash 2, 8, B01000001, B01111111, B00000000, B00000000, B00000000, // ] 3, 8, B00000010, B00000001, B00000010, B00000000, B00000000, // hat 4, 8, B01000000, B01000000, B01000000, B01000000, B00000000, // _ 2, 8, B00000001, B00000010, B00000000, B00000000, B00000000, // ` 4, 8, B00100000, B01010100, B01010100, B01111000, B00000000, // a 4, 8, B01111111, B01000100, B01000100, B00111000, B00000000, //b 4, 8, B00111000, B01000100, B01000100, B00101000, B00000000, // c 4, 8, B00111000, B01000100, B01000100, B01111111, B00000000, // d 4, 8, B00111000, B01010100, B01010100, B00011000, B00000000, // e 3, 8, B00000100, B01111110, B00000101, B00000000, B00000000, // f 4, 8, B10011000, B10100100, B10100100, B01111000, B00000000, // g 4, 8, B01111111, B00000100, B00000100, B01111000, B00000000, // h 3, 8, B01000100, B01111101, B01000000, B00000000, B00000000, // i 4, 8, B01000000, B10000000, B10000100, B01111101, B00000000, // j 4, 8, B01111111, B00010000, B00101000, B01000100, B00000000, // k 3, 8, B01000001, B01111111, B01000000, B00000000, B00000000, // l 5, 8, B01111100, B00000100, B01111100, B00000100, B01111000, // m 4, 8, B01111100, B00000100, B00000100, B01111000, B00000000, // n 4, 8, B00111000, B01000100, B01000100, B00111000, B00000000, // o 4, 8, B11111100, B00100100, B00100100, B00011000, B00000000, // p 4, 8, B00011000, B00100100, B00100100, B11111100, B00000000, // q 4, 8, B01111100, B00001000, B00000100, B00000100, B00000000, // r 4, 8, B01001000, B01010100, B01010100, B00100100, B00000000, // s 3, 8, B00000100, B00111111, B01000100, B00000000, B00000000, // t 4, 8, B00111100, B01000000, B01000000, B01111100, B00000000, // u 5, 8, B00011100, B00100000, B01000000, B00100000, B00011100, // v 5, 8, B00111100, B01000000, B00111100, B01000000, B00111100, // w 5, 8, B01000100, B00101000, B00010000, B00101000, B01000100, // x 4, 8, B10011100, B10100000, B10100000, B01111100, B00000000, // y 3, 8, B01100100, B01010100, B01001100, B00000000, B00000000, // z 3, 8, B00001000, B00110110, B01000001, B00000000, B00000000, //{ 1, 8, B01111111, B00000000, B00000000, B00000000, B00000000, // | 3, 8, B01000001, B00110110, B00001000, B00000000, B00000000, // } 4, 8, B00001000, B00000100, B00001000, B00000100, B00000000, // ~ }; int dIn = 7; // DIN pin of MAX7219 module int clk = 6; // CLK pin of MAX7219 module int cs = 5; // CS pin of MAX7219 module int maxInUse = 2; // Number of MAX7219's connected MaxMatrix m(dIn, cs, clk, maxInUse); SoftwareSerial Bluetooth(8, 7); // Bluetooth byte buffer[10]; char incomebyte; int scrollSpeed = 100; char text[100] = "TechKnowSkola "; // Initial text message int brightness = 15; int count = 0; char indicator; void setup() { m.init(); // MAX7219 initialization m.setIntensity(brightness); // initial led matrix intensity, 0-15 Bluetooth.begin(38400); // Default communication rate of the Bluetooth module } void loop() { // Printing the text printStringWithShift(text, scrollSpeed); if (Bluetooth.available()) { // Checks whether data is comming from the serial port indicator = Bluetooth.read(); // Starts reading the serial port, the first byte from the incoming data // If we have pressed the "Send" button from the Android App, clear the previous text if (indicator == '1') { for (int i = 0; i < 100; i++) { text[i] = 0; m.clear(); } // Read the whole data/string comming from the phone and put it into text[] array. while (Bluetooth.available()) { incomebyte = Bluetooth.read(); text[count] = incomebyte; count++; } count = 0; } // Adjusting the Scrolling Speed else if (indicator == '2') { String sS = Bluetooth.readString(); scrollSpeed = 150 - sS.toInt(); // Milliseconds, subtraction because lower value means higher scrolling speed } // Adjusting the brightness else if (indicator == '3') { String sB = Bluetooth.readString(); brightness = sB.toInt(); m.setIntensity(brightness); } } } void printCharWithShift(char c, int shift_speed) { if (c < 32) return; c -= 32; memcpy_P(buffer, CH + 7 * c, 7); m.writeSprite(32, 0, buffer); m.setColumn(32 + buffer[0], 0); for (int i = 0; i < buffer[0] + 1; i++) { delay(shift_speed); m.shiftLeft(false, false); } } void printStringWithShift(char* s, int shift_speed) { while (*s != 0) { printCharWithShift(*s, shift_speed); s++; } } void printString(char* s) { int col = 0; while (*s != 0) { if (*s < 32) continue; char c = *s - 32; memcpy_P(buffer, CH + 7 * c, 7); m.writeSprite(col, 0, buffer); m.setColumn(col + buffer[0], 0); col += buffer[0] + 1; s++; } } Description: First we need to include the SoftwareSerial.h library which will enable the Bluetooth communication and define some variables needed for the program. In the setup section we need to initialize the Bluetooth at its default baud rate of 38400 bits per second. I set the initial text message to be “TechKnowSkola” with 100 milliseconds delay scrolling speed. Next, in the loop section, using the Bluetooth.available() function we check whether there is incoming data from the serial port and if that’s true using the Bluetooth.read function we start reading the serial port, one byte each iteration. So the first incoming byte will be always stored into the “indicator” variable and according to it choose whether we will change the text message, the scrolling speed or the brightness of the LED matrix. If we take a look at the Android app code blocks we can notice that when the “Send” button is clicked, first we send the indication byte, in this case “1”, which means we want the change the text message. In order to do that, at the Arduino side, we will clear the whole character array and also clear the LED matrix display. Then in the “while” loop we will read the rest of the data in the serial port, and that’s the messaged typed in the text box of the Android app. In case the indication variable is “2”, that means we have changed the position of the scrolling speed slider, so we will read its new value using the Bluetooth.readString() function and adjust the scrolling speed. In the same way we adjust the brightness of the LEDs. You can download the app from the following link: https://drive.google.com/open?id=1xvR_tyTF-zzdrqc6RrdHlcD5FRICIbs5 Reference URL GET IN TOUCH We'd love to hear from you Contact Us

Back Interfacing of Sound sensor with Arduino Uno. What is a Sound Sensor? The Sound Sensor Module provides an easy way to detect sound and is generally used for detecting sound Intensity. This Module can be used Security, Switch and Monitoring applications. Its accuracy can be easily Adjusted for the convenience of the usage. It uses a Microphone which supplies the input to an amplifier, peak detector and buffer. When a Sensor detects a sound , it processes an output signal voltage which is sent to microprocessor , and performs further processing. Material Required: Material Quantity Arduino Uno 1 Sound Sensor 1 Jumper cables 5 Resistor 1(1k ohm) Pinout Diagram: Circuit Diagram: Parameter Value VCC 5 V DC from your Arduino Ground GND from your Arduino Out Connect to Digital Input Pin Tested Programming Code: //Arduino Sound Detection Sensor Module int soundDetectedPin = 10; // Use Pin 10 as our Input int soundDetectedVal = HIGH; // This is where we record our Sound Measurement boolean bAlarm = false; unsigned long lastSoundDetectTime; // Record the time that we measured a sound int soundAlarmTime = 500; // Number of milli seconds to keep the sound alarm high void setup () { Serial.begin(9600); pinMode (soundDetectedPin, INPUT) ; // input from the Sound Detection Module } void loop () { soundDetectedVal = digitalRead (soundDetectedPin) ; // read the sound alarm time if (soundDetectedVal == LOW) // If we hear a sound { lastSoundDetectTime = millis(); // record the time of the sound alarm // The following is so you don't scroll on the output screen if (!bAlarm){ Serial.println("LOUD, LOUD"); bAlarm = true; } } else { if( (millis()-lastSoundDetectTime) > soundAlarmTime && bAlarm){ Serial.println("quiet"); bAlarm = false; } } } Precautions: 1. Double check the connections before powering on the circuit. 2. Don’t use loose jumper cables. 3. Check whether proper board is selected from Arduino IDE. 4. Ensure proper placement of Sound Sensor for correctworking. 5. Don’t lose hope if Sound Sensor does not run properly for the first time, try again. Conclusion: Once your sketch is running, you will want to open your serial monitor. Make some loud noises and and view the results Reference URL GET IN TOUCH We'd love to hear from you Contact Us

Back Interfacing of RFID Module with Arduino Uno. What is RFID? Radio-Frequency Identification ( RFID ) is the use of radio waves to read and capture information stored on a tag attached to an object. A tag can be read from up to several feet away and does not need to be within direct line-of-sight of the reader to be tracked. Material Required: Material Quantity Arduino Uno 1 Rfid module 1 Jumper cables 8 Pinout Diagram: Circuit Diagram: Connect the RFID module with Arduino as follows: GND pin of RFID module to GND of Arduino VCC pin of RFID module to 5V of Arduino SDA pin of RFID module to digital pin 10 of Arduino SCK pin of RFID module to digital pin 13 of Arduino. MOSI pin of RFID module to digital pin 11 of Arduino. MISO pin of RFID module to digital pin 12 of Arduino. RST pin of RFID module to digital pin 9 of Arduino. IRQ pin of RFID module is not connected Download RFID Library We need to download the library for RFID. Go to sketch >> include library >> window open >> go to search bar and type <> you see a link >> click on that link and install. Tested Programming Code: #include #include #define RST_PIN 9 #define SS_PIN 10 MFRC522 rfid(SS_PIN, RST_PIN); MFRC522::MIFARE_Key key; void setup() { Serial.begin(9600); SPI.begin(); rfid.PCD_Init(); } void loop() { if( ! rfid.PICC_IsNewCardPresent()||! rfid.PICC_ReadCardSerial()) { return; } MFRC522::PICC_TypepiccType = rfid.PICC_GetType(rfid.uid.sak); String sd = ""; for (byte i = 0; i < 4; i++) { sd += (rfid.uid.uidByte[i] < 0x10 ? "0" : "") + String(rfid.uid.uidByte[i], HEX) + (i!=3 ? ":" : ""); } sd.toUpperCase(); Serial.print("Tap card key: "); Serial.println(sd); rfid.PICC_HaltA (); rfid.PCD_StopCrypto1 (); } Precautions: Double check the connections before powering on the circuit. Don’t use loose jumper cables. Check whether proper board is selected from Arduino IDE. Ensure proper placement of RFID module Sensor for correct working. Conclusion: Once your sketch is running, you have open serial monitor and then put your RFID tag on RFID module. Reference URL GET IN TOUCH We'd love to hear from you Contact Us

Back Interfacing of LDR Sensor Module with Arduino Uno. What is a LDR Sensor Module ? LDR sensor module is used to detect the intensity of light. It is associated with both analog output pin and digital output pin labelled as AO and DO respectively on the board. When there is light, the resistance of LDR will become low according to the intensity of light. The greater the intensity of light, the lower the resistance of LDR. The sensor has a potentiometer knob that can be adjusted to change the sensitivity of LDR towards light. Material Required: Material Quantity Arduino Uno 1 LDR Sensor Module 1 Jumper cables 4 Pinout Diagram: Circuit Diagram: Parameter Value VCC 5 V DC from your Arduino Ground GND from your Arduino A0 Connect to Analog Pin A0 Tested Programming Code: int sensorPin = A0; // select the input pin for LDR int sensorValue = 0; // variable to store the value coming from the sensor void setup() { Serial.begin(9600); //sets serial port for communication } void loop() { sensorValue = analogRead(sensorPin); // read the value from the sensor Serial.println(sensorValue); //prints the values coming from the sensor on the screen delay(100); } Precautions: 1. Double check the connections before powering on the circuit. 2. Don’t use loose jumper cables. 3. Check whether proper board is selected from Arduino IDE. 4. Ensure proper placement of LDR Sensor Module for correct working. 5. Don’t lose hope if LDR Sensor Module does not run properly for the first time, try again. Conclusion: Once your sketch is running, you have to open your serial monitor to check the readings. Reference URL GET IN TOUCH We'd love to hear from you Contact Us

Back Interfacing of Buzzer with Arduino Uno. What is a Buzzer? Buzzers are used for making beep alarms and tones. They can be used in alarm systems, for keypad feedback, or some games. Lightweight, simple construction and low price make it usable in various applications like car/truck reversing indicators, computers, call bells etc. Material Required: Material Quantity Arduino Uno 1 Buzzer 1 Jumper cables 5 Resistor 1(100 ohms) Pinout Diagram: Circuit Diagram: The Connections are pretty simple: Connect the Supply wire (RED) of the buzzer to the Digital Pin 9 of the Arduino through a 100-ohm resistor. Connect the Ground wire (BLACK) of the buzzer to any Ground Pin on the Arduino. Tested Programming Code: This code is to generate an alarm type of sound. The tone is an Arduino Library to produce a square wave of the specified frequency (and 50% duty cycle) on any Arduino pin. const int buzzerPin = 9; void setup() { Serial.begin(8600); pinMode(buzzerPin, OUTPUT); void loop() { tone(buzzerPin, 50); delay(50); noTone(buzzerPin); delay(100); } } Precautions: 1. Double-check the connections before powering on the circuit. 2. Don’t use loose jumper cables. 3. Check whether the proper board is selected from Arduino IDE. 4. Ensure proper placement of Buzzer for correct working. 5. Don’t lose hope if Buzzer does not run properly for the first time, try again. Conclusion: You can Use Buzzer as an Alarm and many Other Alerting Devices . Reference URL GET IN TOUCH We'd love to hear from you Contact Us

Back Analog Joystick Interfacing with Arduino UNO. What is an Analog Joystick ? Analog joystick produces two voltages; one corresponding to position with respect to X-axis and another corresponding to the position with respect to Y-axis. The voltages produced depend on the position of the joystick. The Analog Joystick is similar to two potentiometers connected together, one for the vertical movement (Y-axis) and other for the horizontal movement (X-axis). The joystick also comes with a Select switch . It can be very handy for retro gaming, robot control or RC cars. Material Required: Material Quantity Arduino Uno 1 Analog Joystick 1 Jumper cables 5 Pinout Diagram: We need 5 connections to the joystick. The connection are : SW( Switch), Y, X, Voltage and Ground. “Y and X” are Analog and “Switch” is Digital. If you don’t need the switch then you can use only 4 pins. Circuit Diagram: This is circuit diagram of Analog Joystick module in Arduino. There five pins in analog Joystick Module VCC, GND, SW, X, and Y. X and Y are Analog pins and SW is digital. Key will be used when Joystick is pressed. Connect VCC of the module to +5v of Arduino and GND of the module to Arduino Ground. Now, connect X to Analog pin A0 and Y to Analog pin A1 of Arduino.. Tested Programming Code: This is code for interfacing analog Joystick Module in Arduino. First initialized the pin numbers of Joystick Module. In setup, the Serial Monitor is started at 9600 Baud and initialized Joystick pins as input. In the loop, read the button state and stored in a variable. Print the values to the Serial Monitor. const int joystick_x_pin = A2; const int joystick_y_pin = A1; void setup() { Serial.begin(9600); /* Define baud rate for serial communication */ } void loop() { int x_adc_val, y_adc_val; float x_volt, y_volt; x_adc_val = analogRead(joystick_x_pin); y_adc_val = analogRead(joystick_y_pin); x_volt = ( ( x_adc_val * 5.0 ) / 1023 ); /*Convert digital value to voltage */ y_volt = ( ( y_adc_val * 5.0 ) / 1023 ); /*Convert digital value to voltage */ Serial.print("X_Voltage = "); Serial.print(x_volt); Serial.print("\t"); Serial.print("Y_Voltage = "); Serial.println(y_volt); delay(100); } Checking Values on Serial Monitor: After Uploading The program Successfully into the Arduino Board , we Can Check the Values of X and Y Serial Monitor The Image of the Serial monitor Is shown Below : Precautions: 1. Double check the connections before powering on the circuit. 2. Don’t use loose jumper cables. 3. Check whether proper board is selected from Arduino IDE. 4. Ensure proper placement of sensor for correct working. 5. Connect the Wiper pin of potentiometer correctly. 6. Don’t lose hope if Joystick does not runs properly for the first time, try again. Conclusion: You can successfully display data on a the Serial Monitor of the Joystick in simplest way using Arduino. Many forms of data can be displayed on this display, whether it can be a data from sensor or anything else. Reference URL GET IN TOUCH We'd love to hear from you Contact Us

Back Measuring soil moisture using Soil Moisture Sensor with Arduino (Y-38) What is a Soil Moisture Sensor? This sensor measures the volumetric content of water inside the soil and gives us the moisture level as output. The sensor is equipped with both analog and digital output, so it can be used in both analog and digital mode. So let’s begin our tutorial on interfacing Arduino and Soil moisture sensor. Specifications: Input Voltage : 3.3– 5V Output Voltage : 4.2V Input Current : 35mA Output Signal : Both Analog and Digital Material Required: Material Quantity Arduino Uno 1 Soil Moisture Sensor 1 Jumper cables 5 Pinout Diagram: The soil Moisture sensor YL-38has four pins VCC: For power A0: Analog output D0: Digital output GND: Ground The Module also contains a potentiometer which will set the threshold value and then this threshold value will be compared by the LM393 comparator. The output LED will light up and down according to this threshold value. Working: The soil moisture sensor consists of two probes which are used to measure the volumetric content of water. The two probes allow the current to pass through the soil and then it gets the resistance value to measure the moisture value. When there is more water, the soil will conduct more electricity which means that there will be less resistance. Therefore, the moisture level will be higher. Dry soil conducts electricity poorly, so when there will be less water, then the soil will conduct less electricity which means that there will be more resistance. Therefore, the moisture level will be lower. This sensor can be connected in two modes; Analog mode and digital mode. First, we will connect it in Analog mode, and then we will use it in Digital mode. Analog Mode – Interfacing Soil Moisture Sensor and Arduino' To connect the sensor in the analog mode, we will need to use the analog output of the sensor. When taking the analog output from the soil moisture sensor FC-28, the sensor gives us the value from 0-1023. The moisture is measured in percentage, so we will map these values from 0 -to 100, and then we will show these values on the serial monitor. You can further set different ranges of the moisture values and turn on or off the water pump according to it. Circuit Diagram: The connections for connecting the soil moisture sensoYL-38 to the Arduino are as follows. VCC of YL-38 to 5V of Arduino GND of YL-38 to GND of Arduino A0 of YL-38 to A0 of Arduino Tested Programming Code: const int soil_sensor = A0; sensor is attached to int sensorValue = 0; void setup() { Serial.begin(9600); } void loop() { sensorValue = analogRead(soil_sensor); serial monitor: Serial.print("Moisture Value = " ); Serial.println(sensorValue); delay(1000); } Digital Mode – Interfacing Arduino and Soil Moisture Sensor To connect the soil moisture sensor YL-38 in the digital mode, we will connect the digital output of the sensor to the digital pin of the Arduino. The Sensor module contains a potentiometer with it, which is used to set the threshold value. This threshold value is then compared with the sensor output value using the LM393 comparator which is placed on the sensor module. The LM393 comparator will compare the sensor output value and the threshold value and then gives us the output through the digital pin. When the sensor value will be greater than the threshold value, then the digital pin will give us 5V and the LED on the sensor will light up and when the sensor value will be less than this threshold value, then the digital pin will give us 0V and the light will go down. Circuit Diagram: The connections for connecting the soil moisture sensor YL-38 to the Arduino in digital mode are as follows. · VCC of YL-38 to 5V of Arduino · GND of YL-38 to GND of Arduino · D0 of YL-38 to pin 12 of Arduino · LED positive to pin 13 of Arduino · LED negative to GND of Arduino Tested Programming Code int led_pin =13; int sensor_pin =8; void setup() { pinMode(led_pin, OUTPUT); pinMode(sensor_pin, INPUT); } void loop() { if(digitalRead(sensor_pin) == HIGH) { digitalWrite(led_pin, HIGH); } else { digitalWrite(led_pin, LOW); delay(1000); } } Precautions: 1. Double check the connections before powering on the circuit. 2. Don’t use loose jumper cables. 3. Check whether the proper board is selected from Arduino IDE. 4. Ensure proper placement of sensor for correct working. 5. Please keep your hardware away from water except, the sensing probe. Conclusion: You can successfully measure the moisture percentage in the soil and control the appropriate flow of water. This sensor can be deployed in many ways like auto irrigation systems, automatic plant watering systems etc. Output: Situation Screenshot: Serial Monitor (Ctrl+Shift+M) Reference URL GET IN TOUCH We'd love to hear from you Contact Us

Back Finding an obstacle using IR Sensor with Arduino What is an Infrared Sensor? An infrared sensor is an electronic instrument which is used to sense certain characteristics of its surroundings by either emitting and/or detecting infrared radiation. Infrared sensors are also capable of measuring the heat being emitted by an object and detecting motion. Material Required: Material Quantity Arduino Uno 1 Infrared Sensor 1 Jumper cables 5 LED Bulb 1 Pinout Diagram: Circuit Diagram: Working: This is a multipurpose infrared sensor which can be used for color detection. The sensor provides a digital as output. An on board LED is used to indicate the presence of an object. This digital output can be directly connected to an Arduino, Raspberry Pi or any other microcontroller to read the sensor output.IR sensors are highly susceptible to ambient light and the IR sensor on this sensor is suitably covered to reduce effect of ambient light on the sensor. The on board potentiometer should be used to calibrate the sensor. An infrared light emitting diode (IR LED) emits light of Infrared range 700 nanometers (nm) to 1 mm. This light is not visible by naked eyes but can be seen by a camera (that is why these are also used in night vision cameras). A photo diode gives response in term of change in resistance when light falls on it. That change is measured in terms of voltage. An IR LED and a Photo diode are used in a combination for proximity and color detection. An IR LED (transmitter) emits IR light, that light gets reflected by the object, the reflected light is received by an IR receiver (Photo Diode). Amount of reflection and reception varies with the distance. This difference causes to change in input voltage through IR input. This variation in input voltage is used for proximity detection. For color detection application: The amount of reflected light depends upon the color of surface from which it is reflected. The reflection is different for different colored surfaces. This makes it a color detector. Tested Programming Code: int LED = 13; // Use the onboard Uno LED int obstaclePin = 2; // This is our input pin int hasObstacle = LOW; // LOW MEANS NO OBSTACLE void setup() { pinMode(LED, OUTPUT); pinMode(obstaclePin, INPUT); Serial.begin(9600); } void loop() { hasObstacle = digitalRead(obstaclePin); //Reads the output of the obstacle sensor from the 7th PIN of the Digital section of the arduino if (hasObstacle == LOW) //LOW means path is clear, so red light connected to 13th Port connected LED is off. { Serial.println("Path is Clear"); digitalWrite(LED, LOW);//Illuminates the 13th Port LED } else { Serial.println("Stop something is ahead!!"); digitalWrite(LED, HIGH); } delay(200); } Precautions: 1. Double Check the connections before powering on the circuit. 2. Don’t use loose jumper cables. 3. Check Whether proper board is selected from Arduino IDE. 4. Ensure proper placement of sensor for correct working. Conclusion: You can successfully check for an obstacle using an IR sensor. Many more other applications can be made using Infrared sensor as it has many possibilities to work with. Output: Place the object in front of IR proximity sensor and observe the change in LED connected to board and Arduino as well. When you remove object you will see it gets turned off. The sensor outputs a logic 1 (+5V) at the digital output when an object is placed in front of the sensor and a logic 0 (0V), when there is no object in front of the sensor. (On Serial Monitor Press Ctrl+Shift+M) Situation 1: When there is no obstacle in front of the sensor. Reference URL GET IN TOUCH We'd love to hear from you Contact Us

Back Interfacing of Rain Drop Sensor with Arduino Uno. What is a Rain Drop Sensor? A raindrop sensor is a board on which nickel is coated in the form of lines. It works on the principle of resistance. The rain Sensor module allows the measurement of moisture via analog output pins and it provides a digital output when a threshold of moisture exceeds. The module is based on the LM393 op amp. It includes the electronics module and a printed circuit board that “collects” the rain drops. As raindrops are collected on the circuit board, they create paths of parallel resistance that are measured via the op amp. Material Required: Material Quantity Arduino Uno 1 Raindrop sensor 1 Jumper cables 4 Pinout Diagram: Circuit Diagram: Vcc +5 Volts Power Source GND Ground or negative power source A0 Analog Output – A0 Tested Programming Code: const int sensorMin = 0; const int sensorMax = 1024; void setup() { Serial.begin(9600); } void loop() { int sensorReading = analogRead(A0); int range = map(sensorReading, sensorMin, sensorMax, 0, 3); switch (range) { case 0: Serial.println("RAINING"); break; case 1: Serial.println("RAIN WARNING"); break; case 2: Serial.println("NOT RAINING"); break; } delay(1000); } Precautions: Double-check the connections before powering on the circuit. Don’t use loose jumper cables. Check whether the proper board is selected from Arduino IDE. Ensure proper placement of Rain drop Sensor for correct working. Don’t lose hope if Rain Drop Sensor does not run properly for the first time, try again. Conclusion: Once your sketch is running, you have to open your serial monitor. There you can see the Moisture or Rain on the Board. Reference URL GET IN TOUCH We'd love to hear from you Contact Us

Back Interfacing of MQ2 (gas) sensor with Arduino Uno. What is a MQ2 (gas) Sensor? The Gas Sensor (MQ2) module is useful for gas leakage detection (home and industry). It is suitable for detecting H2, LPG, CH4, CO, Alcohol, Smoke or Propane. Due to its high sensitivity and fast response time, measurement can be taken as soon as possible. The sensitivity of the sensor can be adjusted by potentiometer. Material Required: Material Quantity Arduino Uno 1 MQ2 (gas) Sensor 1 Jumper cables 6 LED 1 Pinout Diagram: Circuit Diagram: Connect the pulse sensor with Arduino as follows: GND pin of MQ2 (gas) sensor to GND of Arduino VCC of MQ2 (gas) sensor to 5V of Arduino A0 of MQ2 (gas) sensor to A0 of Arduino D0 of MQ2 (gas) sensor to D2 of Arduino. If needed. After that, connect the LED to pin 13 and GND of Arduino as shown in the figure below. The LED will blink according to the MQ2 (gas) sensor. Tested Programming Code: Const int gaspin = A0; float sensorValue ; //variable to store sensor value void setup () { pinMode(gaspin,INPUT); Serial . begin ( 9600 ); // sets the serial port to 9600 Serial . println ( "Gas sensor warming up!" ); delay ( 20000 ); // allow the MQ-6 to warm up } void loop () { sensorValue = analogRead ( gaspin ); // read analog input pin 0 Serial . print ( "Sensor Value: " ); Serial . print ( sensorValue ); if ( sensorValue > 300 ) { Serial . print ( " | Smoke detected!" ); } Serial . println ( "" ); delay ( 2000 ); // wait 2s for next reading } Precautions: 1. Double check the connections before powering on the circuit. 2. Don’t use loose jumper cables. 3. Check whether proper board is selected from Arduino IDE. 4. Ensure proper placement of MQ2 (gas) Sensor for correct working. 5. Don’t lose hope if Sensor does not run properly for the first time, try again. Conclusion: Once your sketch is running, you have to open your serial monitor. There you can see the value of gas present in air by the sensor. Reference URL GET IN TOUCH We'd love to hear from you Contact Us

Back Interfacing of Force Pressure Sensor with Arduino Uno. What is a Force Pressure Sensor? An FSR (Force Sensitive Resistor) or Force Pressure Sensor is a sensor that allows you to measure physical pressure, weight and squeezing. The resistance of an FSR varies as the force on the sensor increases or decreases. When no pressure is being applied to the FSR, its resistance will be larger than 1MΩ. The harder you press on the sensor’s head, the lower the resistance between the two terminals drops. By combining the FSR with a static resistor to create a voltage divider, you can produce a variable voltage that can be read by a microcontroller’s analog-to-digital converter. Material Required: Material Quantity Arduino Uno 1 Force Pressure Sensor 1 Jumper cables 4 LED 1 Resistor 1 ( 10 k) Pinout Diagram: Circuit Diagram: The connections are pretty easy and straight forward. Make the circuit by referring the images. The FSR has two pins, one will be connected to 5V pin. The other to A0 directly and to Gnd pin via a resistor. If you need to connect the LED and control it's brightness, then connect it across pin 13 and Gnd of the Arduino. Tested Programming Code: int fsrPin = 0; // the FSR and 10K pulldown are connected to a0 int fsrReading; // the analog reading from the FSR resistor divider void setup(void) { Serial.begin(9600); } void loop(void) { fsrReading = analogRead(fsrPin); Serial.print("Analog reading = "); Serial.print(fsrReading); // the raw analog reading if (fsrReading == 0) { Serial.println(" - No pressure"); } else if (fsrReading < 10) { Serial.println(" - Light touch"); } else if (fsrReading < 50) { Serial.println(" - Light squeeze"); } else if (fsrReading < 150) { Serial.println(" - Medium squeeze"); } else { Serial.println(" - Big squeeze"); } delay(1000); } Precautions: 1. Double check the connections before powering on the circuit. 2. Don’t use loose jumper cables. 3. Check whether proper board is selected from Arduino IDE. 4. Ensure proper placement of Force Pressure Sensor for correct working. 5. Don’t lose hope if Force Pressure Sensor does not run properly for the first time, try again. Conclusion: Once your sketch is running, you have to open your serial monitor. There you can see the Pressure applied on the sensor as Light , Big or No squeeze. Reference URL GET IN TOUCH We'd love to hear from you Contact Us

Back Interfacing 2 Channel Relay Module with Arduino and control High Voltage AC (current). What is a Relay Module? A Relay is a device that helps microcontrollers (or microcontroller-based boards) like Arduino to switch on or off different household appliances like motors, lights, water heaters, television, fans, etc. The relay module for Arduino is one of the most powerful applications for Arduino as it can be used to control both A.C and D.C devices by simply controlling the relay by giving 5V. A relay is a switch that is operated electrically by an electromagnet. A relay can be used to control high voltage electronic devices such as motors as well as low voltage electronic devices such as a light bulb or a fan. Relays work on the principle of electromagnetism. When the electricity is provided to the relay coil then it acts like a magnet and changes the state of the switch. The part which powers the relay module is completely isolated from the part which turns ON or OFF. This is why we can control a 220V appliance by simply controlling it using the 5V Arduino. you should also read getting started projects of Arduino. Material Required: Material Quantity Arduino Uno 1 Relay module (2 Channel) 1 Jumper cables 6 Switching Source 1 Cable, Plug, Socket 1 Pinout Diagram: HL-52S Relay Module As an example, for this Arduino Relay Tutorial, we will use the HL-52S 2 channel relay module, which has 2 relays with a rating of 10A @ 250 and 125 V AC and 10A @ 30 and 28 V DC. The high voltage output connector has 3 pins, the middle one is the common pin, and as we can see from the markings one of the two other pins is for a normally open connection and the other one for a normally closed connection. On the other side of the module, we have these 2 sets of pins. The first one has 4 pins, a Ground and a VCC pin for powering the module, and 2 input pins In1 and In2. The second set of pins has 3 pins with a jumper between the JDVcc and the Vcc pin. With a configuration like this, the electromagnet of the relay is directly powered by the Arduino Board and if something goes wrong with the relay the microcontroller could get damaged. Circuit Diagram: For better understanding let’s see the circuit schematics of the relay module in this configuration. So we can see that the 5 volts from our microcontroller connected to the Vcc pin for activating the relay through the Optocoupler IC are also connected to the JDVcc pin which powers the electromagnet of the relay. So in this case we got no isolation between the relay and the microcontroller. To isolate the microcontroller from the relay, we need to remove the jumper and connect a separate power supply for the electromagnet to the JDVcc and the Ground pin. Now with this configuration, the microcontroller doesn’t have any physical connection with the relay, it just uses the LED light of the Optocoupler IC to activate the relay. There is one more thing to be noticed from this circuit schematics. The input pins of the module work inversely. As we can see the relay will be activated when the input pin will be LOW because in that way the current will be able to flow from the VCC to the input pin which is low or ground, and the LED will light up and activate the relay. When the input pin will be HIGH there will be no current flow, so the LED will not light up and the relay will not be activated. High Voltage Warning Before we continue with this tutorial, I will warn you here that we will use High Voltage which if incorrectly or improperly used could result in serious injuries or death. So be very cautious of what you are doing because I take no responsibility for any of your actions. How to use the relay module with the High Voltage devices First, let’s take a look at the circuit diagram. As previously described we will use a 5V Adapter as a separate power supply for the electromagnet connected to the JDVcc and the Ground pin. The Arduino’s 5V pin will be connected to the Vcc pin of the module and PIN 7 to the In1 input pin for controlling the relay. Now for the HIGH Voltage part, we need a power plug, a socket, and a cable with two wires. One of the two wires will be cut and connected to the common and the normally open pin of the module output connector. So with this configuration when we will activate the relay we will get the high voltage circuit closed and working. Here’s how made the cable. So I bought a plug, a socket, and a cable. Then I carefully cut the cable and cut one of the wires as shown in the picture below and connect them to the normally open connection pins of the relay module. Also connected the ends of the cable to the plug and the socket. Tested Programming Code: Now what’s left for this tutorial is to make a simple code and test the relay module and how it will work. Here’s the simple code, we will just use the PIN 7 for controlling the relay, so we will define it as output and make a program that will just activate and deactivate the relay every 3 seconds. I will mention once again here that the input of the module works inversely so a logic low at the input will activate the relay and vice versa. int in1 = 7; void setup() { pinMode(in1, OUTPUT); digitalWrite(in1, HIGH); } void loop() { digitalWrite(in1, LOW);delay(3000); digitalWrite(in1, HIGH); delay(3000); } There is a demonstration of this example at the end of the video of this tutorial. I tested 3 devices on it. First a 100W light bulb, then a desk lamp, and a fan heater. All of these devices work on 220V. Precautions: 1. Double-check the connections before powering on the circuit. 2. Don’t use loose jumper cables. 3. Check whether the proper board is selected from Arduino IDE. 4. Ensure proper placement of Relay Module for correct working. 5. Use proper measures before using AC electricity. Conclusion: So that’s how we can control any High Voltage Device using Arduino or any other microcontroller. And of course, the possibilities are now endless, for example, we can control the devices using a TV Remote, Bluetooth, SMS, Internet, and so on. Reference URL GET IN TOUCH We'd love to hear from you Contact Us

Back Interfacing GPS with Arduino (Neo-6M-001) What is a GPS Module? Every single location in the entire globe can be specified in terms of geographical coordinates. The geographical coordinate is a system which specifies any given location on the earth surface as latitude and longitude. There are devices which can read the geographical coordinates of a place with the help of the signals received from a number of satellites orbiting the earth. The system of satellites which helps in the positioning of a place is called Global Positioning System (GPS). The devices which can read the geographical coordinates of a place with the help of at least four GPS satellites are called GPS Receiver or simply GPS module. Specifications: • Build in 18X18mm GPS antenna • Anti-jamming technology • 5Hz position update rate • Operating temperature range: -40 TO 85°C • UART TTL socket • EEprom to store settings Material Required: Material Quantity Arduino Uno 1 GPS Module 1 Jumper cables 4 Working: GPS satellites circle the Earth twice a day in a precise orbit. Each satellite transmits a unique signal and orbital parameters that allow GPS devices to decode and compute the precise location of the satellite. GPS receivers use this information and trilateration to calculate a user's exact location. Essentially, the GPS receiver measures the distance to each satellite by the amount of time it takes to receive a transmitted signal. With distance measurements from a few more satellites, the receiver can determine a user's position and display it. To calculate your 2-D position (latitude and longitude) and track movement, a GPS receiver must be locked on to the signal of at least 3 satellites. With 4 or more satellites in view, the receiver can determine your 3-D position (latitude, longitude and altitude). Generally, a GPS receiver will track 8 or more satellites, but that depends on the time of day and where you are on the earth. Once your position has been determined, the GPS unit can calculate other information, such as: Speed Bearing Track Trip dist istance to destination Download and install required libraries for GPS to work in Arduino IDE (i) SoftwareSerial library (ii) TinyGPS library Click on the highlighted link to download the Library. Circuit Diagram: Connection of Arduino UNO and GPS module : Connect the four pins from UBLOX to an Arduino as follows: Ublox - Arduino GND - GND TX - Digital pin (D3) RX - Digital pin (D4) Vcc - 5Vdc Here, I suggest you to use external power supply to power the GPS module because minimum power requirement for GPS module to work is 3.3 V and Arduino is not capable of providing that much voltage. Tested Programming Code: #include #include SoftwareSerial mySerial(3,4); TinyGPS gps; void gpsdump(TinyGPS &gps); void printFloat(double f, int digits = 2); void setup() { // Oploen serial communications and wait for port to open: Serial.begin(9600); // set the data rate for the SoftwareSerial port mySerial.begin(9600); delay(1000); Serial.println("uBlox Neo 6M"); Serial.print("Testing TinyGPS library v. "); Serial.println(TinyGPS::library_version()); Serial.println("by Mikal Hart"); Serial.println(); Serial.print("Sizeof(gpsobject) = "); Serial.println(sizeof(TinyGPS)); Serial.println(); } void loop() // run over and over { bool newdata = false; unsigned long start = millis(); // Every 5 seconds we print an update while (millis() - start < 5000) { if (mySerial.available()) { char c = mySerial.read(); //Serial.print(c); // uncomment to see raw GPS data if (gps.encode(c)) { newdata = true; break; // uncomment to print new data immediately! } } } if (newdata) { Serial.println("Acquired Data"); Serial.println("-------------"); gpsdump(gps); Serial.println("-------------"); Serial.println(); } } void gpsdump(TinyGPS &gps) { long lat, lon; float flat, flon; unsigned long age, date, time, chars; int year; byte month, day, hour, minute, second, hundredths; unsigned short sentences, failed; gps.get_position(&lat, &lon, &age); Serial.print("Lat/Long(10^-5 deg): "); Serial.print(lat); Serial.print(", "); Serial.print(lon); Serial.print(" Fix age: "); Serial.print(age); Serial.println("ms."); // On Arduino, GPS characters may be lost during lengthy Serial.print() // On Teensy, Serial prints to USB, which has large output buffering and // runs very fast, so it's not necessary to worry about missing 4800 // baud GPS characters. gps.f_get_position(&flat, &flon, &age); Serial.print("Lat/Long(float): "); printFloat(flat, 5); Serial.print(", "); printFloat(flon, 5); Serial.print(" Fix age: "); Serial.print(age); Serial.println("ms."); gps.get_datetime(&date, &time, &age); Serial.print("Date(ddmmyy): "); Serial.print(date); Serial.print(" Time(hhmmsscc): "); Serial.print(time); Serial.print(" Fix age: "); Serial.print(age); Serial.println("ms."); gps.crack_datetime(&year, &month, &day, &hour, &minute, &second, &hundredths, &age); Serial.print("Date: "); Serial.print(static_cast(month)); Serial.print("/"); Serial.print(static_cast(day)); Serial.print("/"); Serial.print(year); Serial.print(" Time: "); Serial.print(static_cast(hour+8)); Serial.print(":"); //Serial.print("UTC +08:00 Malaysia"); Serial.print(static_cast(minute)); Serial.print(":"); Serial.print(static_cast(second)); Serial.print("."); Serial.print(static_cast(hundredths)); Serial.print(" UTC +08:00 Malaysia"); Serial.print(" Fix age: "); Serial.print(age); Serial.println("ms."); Serial.print("Alt(cm): "); Serial.print(gps.altitude()); Serial.print(" Course(10^-2 deg): "); Serial.print(gps.course()); Serial.print(" Speed(10^-2 knots): "); Serial.println(gps.speed()); Serial.print("Alt(float): "); printFloat(gps.f_altitude()); Serial.print(" Course(float): "); printFloat(gps.f_course()); Serial.println(); Serial.print("Speed(knots): "); printFloat(gps.f_speed_knots()); Serial.print(" (mph): "); printFloat(gps.f_speed_mph()); Serial.print(" (mps): "); printFloat(gps.f_speed_mps()); Serial.print(" (kmph): "); printFloat(gps.f_speed_kmph()); Serial.println(); gps.stats(&chars, &sentences, &failed); Serial.print("Stats: characters: "); Serial.print(chars); Serial.print(" sentences: "); Serial.print(sentences); Serial.print(" failed checksum: "); Serial.println(failed); } void printFloat(double number, int digits) { // Handle negative numbers if (number < 0.0) { Serial.print('-'); number = -number; } // Round correctly so that print(1.999, 2) prints as "2.00" double rounding = 0.5; for (uint8_t i=0; i 0) Serial.print("."); // Extract digits from the remainder one at a time while (digits-- > 0) { remainder *= 10.0; int toPrint = int(remainder); Serial.print(toPrint); remainder -= toPrint; }} Precautions: 1. Double check the connections before powering on the circuit. 2. Don’t use loose jumper cables. 3. Check whether proper board is selected from Arduino IDE. 4. Ensure proper placement of sensor for correct working.. Conclusion: You can successfully measure the flow rate and quantity of the water flowing through a pipe through a cross sectional area. This sensor can be deployed in many ways like water level automation system, water meter etc. Output: After you have successfully uploaded your source code, open your serial monitor. Serial monitor will display the data that your gps required. If you didn’t get anything, make sure your connection is correct and try it outside or near the window where it is easy to get the signal. Signal may not reach inside a building. Situation Screenshot: Serial Monitor (Ctrl+Shift+M) Reference URL GET IN TOUCH We'd love to hear from you Contact Us