NTC Temperature Sensor Relay Module

Description

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✅ Description of the Relay Module with NTC Temperature Sensor

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📦 Overview

The Relay Module with NTC Temperature Sensor is an autonomous device that allows you to activate or deactivate an electrical load (e.g., fan, heater, alarm, etc.) based on the ambient temperature. It is equipped with:

• 1-channel relay (typically 10A, compatible with 230V AC or 30V DC)
• NTC temperature sensor (thermistor)
• Potentiometer/trimmer to adjust the activation threshold
• Comparator (LM393 or similar)
• LED for relay status

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⚙️ Technical Specifications

Feature	Value
Operating Voltage	12V DC
Relay Type	1 Channel, 10A @ 250VAC / 10A @ 30VDC
Sensor	NTC Thermistor 10kΩ
Threshold Adjustment	Mechanical Trimmer
Interface	OUT (relay signal), VCC, GND
Relay Output	NC (Normally Closed), NO, COM
LED Indicator	Relay Status (ON/OFF)

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🧠 Operation

1. The NTC sensor reads the temperature.
2. The module compares the reading to a manually set threshold via the potentiometer.
3. When the temperature exceeds or falls below this threshold (depending on the module), the relay activates or deactivates.
4. The onboard LED indicates the relay’s status.

🔁 Typical Behavior: The relay activates at higher temperatures than the threshold, useful for fans or coolers.

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🧰 Guide to Using with Arduino

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🔌 Basic Connections

⚠️ The module operates independently, but we can use Arduino to read the relay’s status o check other events when activated.

Recommended connections:

Module Pin	Connection
VCC (12V)	12V DC Power Supply (NOT from Arduino)
GND	Common GND with Arduino
OUT (signal)	Arduino Digital Pin (e.g., D2)
COM/NO/NC relay	Load to activate/deactivate

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🧪 Example 1: Reading the state of the relay with Arduino

In this example, Arduino detects if the relay is active (i.e., if the temperature has exceeded the threshold):

#define RELAY_SIGNAL 2
#define LED 13 // LED onboard

void setup() {
 pinMode(RELAY_SIGNAL, INPUT);
 pinMode(LED, OUTPUT);
 Serial.begin(9600);
}

void loop() {
 int stato = digitalRead(RELAY_SIGNAL);

 if (stato == HIGH) {
 Serial.println("Temperatura alta - Relè attivo");
 digitalWrite(LED, HIGH);
 } else {
 Serial.println("Temperatura bassa - Relè disattivo");
 digitalWrite(LED, LOW);
 }

 delay(500);
}

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🧪 Example 2: Activation of another device from Arduino

You can use Arduino to activate a buzzer or send a message via serial or WiFi when the relay activates.

#define RELAY_SIGNAL 2
#define BUZZER 3

void setup() {
 pinMode(RELAY_SIGNAL, INPUT);
 pinMode(BUZZER, OUTPUT);
}

void loop() {
 int stato = digitalRead(RELAY_SIGNAL);

 if (stato == HIGH) {
 digitalWrite(BUZZER, HIGH); // Allarme
 } else {
 digitalWrite(BUZZER, LOW);
 }
}

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🔧 Temperature Threshold Adjustment

• Rotate the trimmer on the module clockwise or counterclockwise to change the threshold.
• Use a lighter or the heat of your hand to test the sensitivity.
• The relay will automatically switch when the NTC sensor reaches the set temperature.

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🧪 Practical Usage Examples

Application	Description
Automatic Ventilation	Activates a fan if the temperature is too high
Heating Control	Turns on a heater if the temperature is too low
Overheating Alarm	Sends a signal to Arduino to notify critical temperature
Automatic Greenhouse System	Regulates window opening, fan activation, or pump operation
Electronic Protection	Deactivate loads in case of overheat

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📌 Final Considerations

• ✅ Advantages: simple, economical, reliable, autonomous
• ❌ Limitations: not as precise as a digital sensor (e.g., DS18B20)
• ⚠️ Do not power it with Arduino’s 5V: it requires a separate 12V DC power supply
• 🧩 Can be combined with Arduino, ESP32, or other microcontrollers for advanced projects

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GENERAL	MODEL	Thermal sensor; combo module
MATERIALS	pcb + components
COMPATIBILITY	ARDUINO
ELECTRICAL COMPONENTS	INPUT VOLTAGE	5V
WEIGHT AND DIMENSIONS	PRODUCT WEIGHT	100g
PACKAGE WEIGHT	0.155 kg
PRODUCT DIMENSIONS (L x W x H)	5.5 x 2.7 x 2.7 cm
PACKAGE DIMENSIONS (L x W x H)	5 x 10 x 5 cm
PACKAGE CONTENT	PACKAGE CONTENT	1 x Module

We have available the technical specifications of all components, if not present in the product download card, send us a message through the contact form and we will publish as soon as possible on our website.

Tutorial: How to Use the Relay Module with NTC Thermal Sensor

This module allows you to control electrical devices based on temperature. Useful for home and industrial automation projects.

What you need

• Arduino
• Connection Wires
• Multimeter

Steps

1. 1. Module installation: Place the relay on the Arduino, ensure that the contacts fit correctly.
2. 2. NTC connection: Connect pin A0 to the NTC sensor. Check the datasheet.
3. 3. Relay connection: Connect pin 9 to the relay, check the datasheet.
4. 4. Ground connections: Connect the ground to the relay and the Arduino.
5. 5. Program the relay: Use a sketch to control the relay state based on temperature.
6. 6. Module testing: Turn on the Arduino and observe the relay state.
7. 7. Adjustment: Adjust the relay value for the activation temperature.
8. 8. Test: Activate an electrical device with the relay.

Example code

int sensorPin = A0; int relayPin = 9; void setup() { pinMode(relayPin, OUTPUT); } void loop() { int sensorValue = analogRead(sensorPin); int relayState = (sensorValue > 512) ? HIGH : LOW; digitalWrite(relayPin, relayState); delay(1000); }

Mini project

Create a thermal alarm system for a critical area.

Common mistakes

• Forget to ground the module.
• Incorrect pin connections.
• Not calibrating the relay properly.
• Failing to test the system.

Recommended accessories

• High current relay
• Digital thermometer
• Protective circuit

Frequently asked questions

The relay does not respond correctly.
Check the correct connection and the threshold value.

How can I calibrate the relay?
Adjust the relay value for the desired activation temperature.

What are the advantages of this module?
It allows automating temperature-based systems, optimizing resource usage.