Introduction

The TEC1-12705 is a 12V Peltier module that uses the thermoelectric effect to transfer heat from one side to the other when DC power is applied. It can be used for cooling, heating, or temperature stabilization in various DIY projects.

Key Features

Technical Specifications

Pin Configuration

Wire Color	Function	Connection
Red	Positive (+)	12V DC
Black	Negative (-)	GND

Basic Wiring

// Basic Connection:
// Red Wire → 12V Power Supply (+)
// Black Wire → Power Supply GND (-)
// Heat Sink → MUST be attached to hot side

Arduino Control with Relay

const int relayPin = 3;

void setup() {
  pinMode(relayPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  // Turn on Peltier (cooling mode)
  digitalWrite(relayPin, HIGH);
  Serial.println("Cooling ON");
  delay(5000);
  
  // Turn off Peltier
  digitalWrite(relayPin, LOW);
  Serial.println("Cooling OFF");
  delay(5000);
}

Temperature Control with Arduino

#include <DHT.h>
#define DHTPIN 2
#define DHTTYPE DHT11
#define RELAY_PIN 3
#define TARGET_TEMP 18  // Target temperature in °C

DHT dht(DHTPIN, DHTTYPE);

void setup() {
  pinMode(RELAY_PIN, OUTPUT);
  dht.begin();
  Serial.begin(9600);
}

void loop() {
  float currentTemp = dht.readTemperature();
  
  if (isnan(currentTemp)) {
    Serial.println("Failed to read temperature!");
    return;
  }

  Serial.print("Current Temp: ");
  Serial.print(currentTemp);
  Serial.println("°C");

  if (currentTemp > TARGET_TEMP) {
    digitalWrite(RELAY_PIN, HIGH);
    Serial.println("Cooling ON");
  } else {
    digitalWrite(RELAY_PIN, LOW);
    Serial.println("Cooling OFF");
  }
  
  delay(2000);
}

Cooling System Design Tips

Troubleshooting