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Arduino UNO-Based Smart Temperature Control System with LCD Display and Relay Modules

Image of Arduino UNO-Based Smart Temperature Control System with LCD Display and Relay Modules

Circuit Documentation

Summary

This circuit involves multiple components including resistors, NTC thermistors, an I2C LCD screen, an Arduino UNO, a battery, LED tactile button breakouts, relay modules, a Peltier module, a water pump, and a fan. The circuit is designed to interface with sensors and actuators, controlled by two Arduino UNO microcontrollers. The circuit also includes an I2C LCD screen for display purposes.

Component List

  1. Resistor

    • Description: A passive electrical component with a resistance of 10k Ohms.
    • Pins: pin1, pin2

  2. Arduino UNO

    • Description: A microcontroller board based on the ATmega328P.
    • Pins: UNUSED, IOREF, Reset, 3.3V, 5V, GND, Vin, A0, A1, A2, A3, A4, A5, SCL, SDA, AREF, D13, D12, D11, D10, D9, D8, D7, D6, D5, D4, D3, D2, D1, D0

  3. NTC Thermistor

    • Description: A type of resistor whose resistance varies significantly with temperature.
    • Pins: A0, A1

  4. I2C LCD 16x2 Screen

    • Description: A 16x2 character LCD screen with I2C interface.
    • Pins: SCL, SDA, VCC (5V), GND, VDD, VO, RS, RW, E, D0, D1, D2, D3, D4, D5, D6, D7, BLA, BLK

  5. Battery

    • Description: A power source for the circuit.
    • Pins: -, +

  6. LED Tactile Button Breakout

    • Description: A breakout board for an LED tactile button.
    • Pins: C, B1, B2, A

  7. Relay Module 5V-30V

    • Description: A relay module that can be triggered by a 5V-30V signal.
    • Pins: common contact, normally open, normally closed, trigger, V-, V+

  8. Peltier Module

    • Description: A thermoelectric cooler.
    • Pins: Negative, Positive

  9. Water Pump

    • Description: A small water pump.
    • Pins: VCC, GND

  10. Fan

    • Description: A small fan.
    • Pins: GND, 5V

Wiring Details

Resistor

  • Resistor 1

    • pin1: Connected to pin1 of another resistor, B2 of two LED tactile button breakouts, - of the battery, and GND of the Arduino UNO.
    • pin2: Connected to A1 of the Arduino UNO and A0 of an NTC thermistor.

  • Resistor 2

    • pin1: Connected to pin1 of another resistor, B2 of two LED tactile button breakouts, - of the battery, and GND of the Arduino UNO.
    • pin2: Connected to A0 of the Arduino UNO and A0 of another NTC thermistor.

Arduino UNO

  • Arduino UNO 1

    • 5V: Connected to VCC (5V) of the I2C LCD screen, + of the battery, and A1 of two NTC thermistors.
    • GND: Connected to pin1 of two resistors, B2 of two LED tactile button breakouts, and - of the battery.
    • A1: Connected to pin2 of a resistor and A0 of an NTC thermistor.
    • A0: Connected to pin2 of another resistor and A0 of another NTC thermistor.
    • A4: Connected to SDA of the I2C LCD screen.
    • A5: Connected to SCL of the I2C LCD screen.
    • D8: Connected to B1 of an LED tactile button breakout.
    • D7: Connected to B1 of another LED tactile button breakout.
    • D6: Connected to the trigger of a relay module.
    • D2: Connected to the trigger of another relay module.

  • Arduino UNO 2

    • 5V: Connected to V+ and common contact of three relay modules, and + of another battery.
    • GND: Connected to V- of three relay modules, B2 of an LED tactile button breakout, and - of another battery.
    • D8: Connected to the trigger of a relay module.
    • D7: Connected to B1 of an LED tactile button breakout.

NTC Thermistor

  • NTC Thermistor 1

    • A0: Connected to pin2 of a resistor and A0 of the Arduino UNO.
    • A1: Connected to A1 of another NTC thermistor, VCC (5V) of the I2C LCD screen, + of the battery, and 5V of the Arduino UNO.

  • NTC Thermistor 2

    • A0: Connected to pin2 of another resistor and A0 of the Arduino UNO.
    • A1: Connected to A1 of another NTC thermistor, VCC (5V) of the I2C LCD screen, + of the battery, and 5V of the Arduino UNO.

I2C LCD 16x2 Screen

  • SCL: Connected to A5 of the Arduino UNO.
  • SDA: Connected to A4 of the Arduino UNO.
  • VCC (5V): Connected to A1 of two NTC thermistors, + of the battery, and 5V of the Arduino UNO.
  • GND: Connected to GND of the Arduino UNO.

Battery

  • Battery 1

    • +: Connected to VCC (5V) of the I2C LCD screen, A1 of two NTC thermistors, and 5V of the Arduino UNO.
    • -: Connected to pin1 of two resistors, B2 of two LED tactile button breakouts, and GND of the Arduino UNO.

  • Battery 2

    • +: Connected to V+ and common contact of three relay modules, and 5V of the Arduino UNO.
    • -: Connected to V- of three relay modules, B2 of an LED tactile button breakout, and GND of the Arduino UNO.

LED Tactile Button Breakout

  • LED Tactile Button Breakout 1

    • B1: Connected to D8 of the Arduino UNO.
    • B2: Connected to pin1 of two resistors, - of the battery, and GND of the Arduino UNO.

  • LED Tactile Button Breakout 2

    • B1: Connected to D7 of the Arduino UNO.
    • B2: Connected to pin1 of two resistors, - of the battery, and GND of the Arduino UNO.

  • LED Tactile Button Breakout 3

    • B1: Connected to D7 of another Arduino UNO.
    • B2: Connected to V- of three relay modules, - of another battery, and GND of another Arduino UNO.

Relay Module 5V-30V

  • Relay Module 1

    • V+: Connected to 5V of another Arduino UNO and + of another battery.
    • V-: Connected to GND of another Arduino UNO, B2 of an LED tactile button breakout, and - of another battery.
    • trigger: Connected to D6 of the Arduino UNO.
    • common contact: Connected to V+ of another Arduino UNO and + of another battery.
    • normally open: Connected to 5V of the fan.

  • Relay Module 2

    • V+: Connected to 5V of another Arduino UNO and + of another battery.
    • V-: Connected to GND of another Arduino UNO, B2 of an LED tactile button breakout, and - of another battery.
    • trigger: Connected to D2 of the Arduino UNO.
    • common contact: Connected to + of another battery.
    • normally open: Connected to Positive of the Peltier module.

  • Relay Module 3

    • V+: Connected to 5V of another Arduino UNO and + of another battery.
    • V-: Connected to GND of another Arduino UNO, B2 of an LED tactile button breakout, and - of another battery.
    • trigger: Connected to D8 of another Arduino UNO.
    • common contact: Connected to + of another battery.
    • normally open: Connected to VCC of the water pump.

Peltier Module

  • Negative: Connected to GND of the water pump and - of another battery.
  • Positive: Connected to normally open of a relay module.

Water Pump

  • GND: Connected to Negative of the Peltier module and - of another battery.
  • VCC: Connected to normally open of a relay module.

Fan

  • GND: Connected to V- of three relay modules, B2 of an LED tactile button breakout, and - of another battery.
  • 5V: Connected to normally open of a relay module.

Documented Code

Arduino UNO 1

void setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here,