Published April 18, 2022

Room Monitor Sensor

Have you wondered what the specific temperature of a room is and if someone goes into said room. This product helps with that.

IntermediateFull instructions provided212

Things used in this project

Hardware components

Particle Argon

DHT11 Temperature & Humidity Sensor (3 pins)

Active Buzzer

HC SR501 PIR Motion Sensor

LCD 1602 Module

Breadboard (generic)

Single Turn Potentiometer- 10k ohms

Software apps and online services

Particle Build Web IDE

IFTTT Maker service

Autodesk Tinkercad

Story

What Problem is Being Solved?

Our group is trying to make a device that will detect movement when entering a room while at the same time reading temperature. The temperature sensor will be hooked to two led lights that have two different lights a red one for when the temperature goes above and blue for when it goes below. Then the motion sensor will be hooked up to sense when someone enters the room. The motion sensor will set off a buzzer that will go off when it detects motion.

How useful is this product?

This product will allow the user to monitor the temperature change in a certain room and also allow monitoring when someone goes into said room. This increases security for a room with the motion sensor and it also allows the user to keep an eye on the temperature of a room to make sure it doesn't change too much.

Why would someone want this product?

This product is for someone that likes to keep their room to a certain temperature and likes to monitor whether or not that temperature is maintained. This will also be used for an alert for any unsuspected visitors.

How it works:

Motion Sensor

How the motion sensor works is that once someone walks into the room, the motion sensor will trigger the buzzer to go off. This will also be hooked to a light that will turn on when motion is detected in the room. Once the buzzer is triggered, it will be on for a set amount of time before shutting off.

Temperature Sensor

How the temperature sensor works is that there will be a certain range for the temperature by a couple of degrees and when the temperature goes higher or lower room temperature, then it will send a signal to the LED lights to light up. In order to imitate the increase and decrease of temperature, we used a lighter to heat up the temperature sensor to show it changing to the red LED and blew on the temperature sensor to cool it and show the blue LED.

Active Buzzer

How the buzzer works is that it is set to the motion sensor. When the motion sensor detects motion, the buzzer will go off for a set amount of time to alert the user that it has detected motion.

Module Display

How the module display works is that it will read from the temperature sensor, and it will display on the screen the temperature when the LED lights go off and changes color between red and blue. When the LED changes color, it will display the temperature at that moment.

10k Ohm Potentiometer

This Potentiometer was used to adjust the resistance to allow the LCD to display properly. Without it, the display would not show the temperature reading from the temperature sensor when there was a change in the color of LED.

Pictures of the Circuit

This is a picture of the circuit that had the motion and temperature sensors. This circuit communicates with the other circuit that has the LCD display by telling the display when the temperature sensor changes the LED color.

This circuit is the one with the LCD display on it. This receives the signal from the other argon on the other circuit when the temperature sensor goes off and it displays what the temperature is when it changes the LED color.

Circuit Schematics

This schematic is the circuit with the temperature and motion sensor on it. On this schematic, it is shown that 2 breadboards were used but we condensed the circuit into one breadboard with both motion and temperature sensor on it. These schematics also were made in TinkerCAD and when we were making it, they did not have an option for argon, so we used an Arduino instead. All of the connections shown on the Arduino were converted to the argon connections.

This schematic shows the circuit with the LCD display on it. All of the connections that are used in the argon are in the code for the LCD display.

YouTube Video

Code

// C++ code
//

//set all pin names
int tempSensor = A5;
int redLED = D2;
int blueLED = D7;
int pirSensor = D0;
int buzzer = D3;
int voltage = 0;
int temp = 0;

void setup()
{

  //set the variables to be sent to other argon
  Particle.variable("temp", temp);


  //Set all the pinmodes
  pinMode(tempSensor, INPUT);
  pinMode(blueLED, OUTPUT);
  pinMode(redLED, OUTPUT);
  pinMode(pirSensor, INPUT);
  pinMode(buzzer, OUTPUT);
  Serial.begin(9600);
}

void loop()
{
  //make sure buzzer is turned off 
  digitalWrite(buzzer, LOW);

  //read the voltage from the temp sensor
  voltage = analogRead(tempSensor);

  //convert the voltage to temp 
  temp = (voltage *-.08099688473520249+82.99688473520249);

  //send the temp to other argon
  Particle.publish("TempIOT042", String(temp), ALL_DEVICES);

  //print out the date 
  Serial.print(temp); // display temperature value
  Serial.print("'");

  //if temp is high show red
  if (temp > 73) {
    digitalWrite(redLED, HIGH);
    digitalWrite(blueLED, LOW);
  }

  //if temp is low show blue
  else if (temp <= 73) {
    digitalWrite(blueLED, HIGH);
    digitalWrite(redLED, LOW);
  }

  //if temp is not reading show nothing
  else {
    digitalWrite(blueLED, LOW);
    digitalWrite(redLED, LOW);
  }

  //read motion sensor
  int pirRead=digitalRead(pirSensor);

  //print out motion data
  Serial.print(pirRead); 
  Serial.print("'");

  //if motion is detected sturn on buzzer for 1 second then turn off
  if (pirRead == HIGH) {
    digitalWrite(buzzer,HIGH);
    delay(1000);
    digitalWrite(buzzer,LOW);
  }




  delay(2000); // Wait for 2000 millisecond(s)
}

// This #include statement was automatically added by the Particle IDE.
#include <LiquidCrystal_I2C_Spark.h>

// This #include statement was automatically added by the Particle IDE.
#include <LiquidCrystal.h>

#include "application.h"

/*
  LiquidCrystal Library 
  The circuit:
 * LCD RS pin to digital pin D0
 * LCD EN pin to digital pin D1
 * LCD D4 pin to digital pin D2
 * LCD D5 pin to digital pin D3
 * LCD D6 pin to digital pin D4
 * LCD D7 pin to digital pin D5
 * 10K resistor:
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)
 * connect R/W (pin 5) to ground

 /


//pinout on LCD [RS, EN, D4, D5, D6, D7];
// pin nums LCD  [ 4,  6, 11, 12, 13, 14];
// Shield Shield [RS, EN, D4, D5, D6, D7];
// Spark Core    [D3, D5, D2, D4, D7, D8];
LiquidCrystal lcd(D0, D1, D2, D3, D4, D5);

//method for getting temp from other argon
int temperature;
void temper(const charevent, const char *data )
{
    String pew = data;
    temperature = pew.toInt();
}



void setup() {

  //Subscribe to other argon for temperature
  Particle.subscribe("TempIOT042", temper, ALL_DEVICES);

  // set up the LCD's number of columns and rows: 
  lcd.begin(16,2);

  // Print a message to the LCD.
  lcd.print("Temperature: ");

}

void loop() {

  //print out data for csv
  Serial.print("Temperature: "); // display temperature value
  Serial.print(temperature); // display temperature value

  //set lcd to second line
  lcd.setCursor(0, 1);
  // print the temperature
  lcd.print(temperature);
  lcd.print("' Farenheit");

  //add small delay
  delay (2000);

  }

Credits

Dylan Collins

2 projects • 0 followers

Colin Shinn

1 project • 0 followers

Room Monitor Sensor