Overheating alarm

In this video, I'll given a simple demo of the alarm I built using Arduino UNO interfaced with DHT11 Temperature sensor and a Buzzer.

Simple Arduino Breathalyzer

Simple Arduino Breathalyzer

 Introduction

The MQ series of gas sensors use a small heater inside with an electro-chemical sensor.
They can be calibrated more or less but a know concentration of the measured gas or gasses is needed for that. 
 They are sensitive for a range of gasses and are used indoors at room temperature.
The output is an analog signal and can be read with an analog input of the Arduino. 

SainSmart MQ-3
The analog gas sensor - MQ3 is used in gas leakage detecting equipments in consumer and industry markets, this sensor is suitable for detecting LPG, i-butane, propane, methane ,alcohol, Hydrogen, smoke.
It has a high sensitivity and fast response time.And the sensitivity can be adjusted by the potentiometer.

 The MQ-3 is an alcohol gas sensor that is available for about $5.

 Connetting

 Sensor-Arduino 

    GND - GND
    A0   -  A0
    VCC -   5V


Arduino Schetch

Test Code: 


int val=0;

void setup(){

Serial.begin(9600);
}

void loop(){

val=analogRead(A0);

Serial.println(val);

delay(100);
}

Link App

https://drive.google.com/file/d/1naIS3WD_Boty_EjX_9em6Vw1NMy59dps/view?usp=sharing

Arduino Tutorial - Easy secret knock detector

In this project I build a circuit with a Led and a piezo to function as a on and off a Led when it receives a number of knocking sounds within a given range.

Step 1: Things you need

 Hardware

• LED
• Diode(Zener 5.1v).
• Piezo Buzzer
• 470Ω Resistor
• 1MΩ Resistor
• Arduino uno
• jumper wire
• Breadboard

Software

• Arduino IDE

Step 2: Watch the video tutorial

Step 3: Schematics

 

The circuit is so simple:
Arduino Pins: Breadboard:
Pin A2 --------------------------1MΩ-------------------Gnd
Pin A2 ------------------------Diode-------------------Gnd
Pin A2 ------------------Piezo Buzzer---------------Gnd
Pin 8 -------------------------470Ω-------Led 1------Gnd
Gnd-------------------------------------------------------Gnd

Step 4: Arduino Sketch

"const int outputPin = 5; // led indicator connected to digital pin const int knockSensor = A2; // the piezo is connected to an analog pin const int thresholdHIGH =120; // threshold value to decide when the detected knock is hard (HIGH) const int thresholdLOW = 70; // threshold value to decide when the detected knock is gentle (LOW) const int secretKnockLength = 3; //How many knocks are in your secret knock /* This is the secret knock sequence * 0 represents a LOW or quiet knock * 1 represents a HIGH or loud knock * The sequence can be as long as you like, but longer codes increase the difficulty of matching */ const int secretKnock[secretKnockLength] = {0, 0, 1}; int secretCounter = 0; //this tracks the correct knocks and allows you to move through the sequence int sensorReading = 0; // variable to store the value read from the sensor pin void setup() { //Set the output pin as an OUTPUT pinMode(outputPin, OUTPUT); //Begin Serial Communication. Serial.begin(9600); } void loop() { // read the piezo sensor and store the value in the variable sensorReading: sensorReading = analogRead(knockSensor); // First determine is knock if Hard (HIGH) or Gentle (LOW) //Hard knock (HIGH) is detected if (sensorReading >= thresholdHIGH) { //Check to see if a Hard Knock matches the Secret Knock in the correct sequence. if (secretKnock[secretCounter] == 1) { //The Knock was correct, iterate the counter. secretCounter++; Serial.println("Correct"); } else { //The Knock was incorrect, reset the counter secretCounter = 0; Serial.println("Fail"); digitalWrite(outputPin, LOW); }//close if //Allow some time to pass before sampling again to ensure a clear signal. delay(100); //Gentle knock (LOW) is detected } else if (sensorReading >= thresholdLOW) { //Check to see if a Gentle Knock matches the Secret Knock in the correct sequence. if (secretKnock[secretCounter] == 0) { //The Knock was correct, iterate the counter. secretCounter++; Serial.println("Correct"); } else { //The Knock was incorrect, reset the counter. secretCounter = 0; Serial.println("Fail"); }//close if //Allow some time to pass before sampling again to ensure a clear signal. delay(100); }//close if else //Check for successful entry of the code, by seeing if the entire array has been walked through. if (secretCounter == (secretKnockLength) ) { Serial.println("Welcome"); //if the sececret knock is correct, illuminate the LED for a couple seconds digitalWrite(outputPin, HIGH); //Reset the secret counter to 0. secretCounter = 0; }//close success check }//close loop".

 

Arduino Tutorial How to control Arduino with Bluetooth

 Arduino Tutorial

In this tutorial I'll show you How to control Arduino with Bluetooth
using, My app developed with app inventor.

Parts Required

• 1x Arduino
• 1x Bluetooth Module ( HC-06)
• 1x Smartphone (any Android will work)
• 1x Led
• 3x resistors
• 1x Breadboard
• Jumper Cables

Schematics 

Arduino Sketch

int ledblue=2;

int tx=1;

int rx=0;

char inSerial[15];

void setup(){

Serial.begin(9600);

pinMode(ledblue, OUTPUT);

pinMode(tx, OUTPUT);

pinMode(rx, INPUT);

allpinslow();

}

void loop(){

int i=0;

int m=0;

delay(500);

if (Serial.available() > 0) {

while (Serial.available() > 0) {

inSerial[i]=Serial.read();

i++;

}

inSerial[i]='\0';

Check_Protocol(inSerial);

}}

void allpinslow()

{

digitalWrite(ledblue, HIGH);

digitalWrite(ledblue, LOW);

}

void Check_Protocol(char inStr[]){

int i=0;

int m=0;

Serial.println(inStr);

if(!strcmp(inStr,"2off")){ //Led Off

allpinslow();

digitalWrite(ledblue, LOW);

Serial.println("Blue Off");

for(m=0;m<11;m++){

inStr[m]=0;}

i=0;}

if(!strcmp(inStr,"2on")){ //Led on

allpinslow();

digitalWrite(ledblue, HIGH);

Serial.println("Blue on");

for(m=0;m<11;m++){

inStr[m]=0;}

i=0;}

else{

for(m=0;m<11;m++){

inStr[m]=0;

}

i=0;

}}

Notes and Tips:

•  You need to remove the RX and TX cables when you’re uploading the sketch to your Arduino.
• If the HC-05 Bluetooth Module asks for a password, It’s’1234′.
• Sometimes people connect the TX from the bluetooth module to the TX of the Arduino… that’s wrong and it won’t work. Make sure you connect it properly, the TX into RX and the RX into the TX.

           

Dht11 Temperature and Humidity Sensor

The DHT11 is a basic,  low-cost digital temperature and humidity sensor.

 Its fairly simple to use, but requires careful timing to grab data. 

Technical Details


    Low Cost
    3 to 5V power and I/O
    2.5mA max current
    Good for 20-80% humidity readings with 5% accuracy
    Good for 0-50°C temperature readings ±2°C accuracy
    No more than 1 Hz sampling rate (once every second)
    Body size 15.5mm x 12mm x 5.5mm   


Test sketch

//

//   FILE:  dht11_test1.pde

// PURPOSE: DHT11 library test sketch for Arduino

//

#include <dht11.h>

dht11 DHT;

#define DHT11_PIN 7


void setup(){

  Serial.begin(9600);

  Serial.println("DHT TEST PROGRAM ");

  Serial.print("LIBRARY VERSION: ");

  Serial.println(DHT11LIB_VERSION);

  Serial.println();

  Serial.println("Type,\tstatus,\tHumidity (%),\tTemperature (C)");

}


void loop(){

  int chk;

  Serial.print("DHT11, \t");

  chk = DHT.read(DHT11_PIN);    // READ DATA

  switch (chk){

    case DHTLIB_OK: 

                Serial.print("OK,\t");

                break;

    case DHTLIB_ERROR_CHECKSUM:

                Serial.print("Checksum error,\t");

                break;

    case DHTLIB_ERROR_TIMEOUT:

                Serial.print("Time out error,\t");

                break;

    default:

                Serial.print("Unknown error,\t");

                break;

  }

 // DISPLAT DATA

  Serial.print(DHT.humidity,1);

  Serial.print(",\t");

  Serial.println(DHT.temperature,1);


  delay(1000);


}


    A tutorial on how to connect a DHT11  Sensor to your Arduino