SENSORS/ACTUATORS

ESP32 C3 Super Mini - Control Heating Element

Learn how to control a heating element with your ESP32 C3 Super Mini microcontroller using a relay module. This beginner-friendly tutorial shows you everything you need to build heating control projects.

In this tutorial, you'll learn:

What a heating element is and how it works with ESP32
How to wire a heating element safely using a relay
How to write ESP32 code to control heating on/off cycles
How to build the foundation for heating system projects
How to drive the heater with a MOSFET module and pick its heat level

You can switch the heater through a relay, or through a MOSFET module. The relay knows only ON and OFF. The MOSFET module also switches ON and OFF, but it can set how much power the heater gets, so you choose a low, medium or high heat level. It is silent, and switching often does not wear it out. We cover both ways here.

ESP32 C3 Super Mini - Controls Heating Element

Hardware Preparation

1	×	ESP32 C3 Super Mini
1	×	USB Cable Type-A to Type-C (for USB-A PC)
1	×	USB Cable Type-C to Type-C (for USB-C PC)
1	×	Relay
1	×	Alternatively, MOSFET Module (AOD4184, LR7843 or FR120N)
1	×	Heating Element
1	×	12V Power Adapter
1	×	Optionally, DC Power Jack
1	×	Breadboard
1	×	Jumper Wires

Or you can buy the following kits:

DIYables Sensor Kit (18 sensors/displays)

Disclosure: Some of the links provided in this section are Amazon affiliate links. We may receive a commission for any purchases made through these links at no additional cost to you.
Additionally, some of these links are for products from our own brand, DIYables .

Overview of Heating Element

A heating element is an electrical component that converts electrical energy into heat when powered.

Key features:

Operates on 12V DC power supply
Generates heat when current flows through it
Requires relay control for ESP32 C3 Super Mini compatibility
Commonly used in warming and temperature control projects
Perfect for learning basic heating system automation

Why use with ESP32:

Build automated heating projects
Create temperature-controlled systems
Learn real-world IoT applications
Practice safe relay-based device control

Pinout

The heating element has a simple two-pin configuration for power connection.

Positive (+) pin (red): Connects to 12V positive terminal of DC power supply
Negative (-) pin (black): Connects to GND negative terminal of DC power supply

How to Control Heating Element

The ESP32 C3 Super Mini controls the heating element indirectly through a relay module.

Control mechanism:

ESP32 C3 Super Mini cannot directly power 12V heating elements
A relay acts as an electronic switch between power supply and heating element
ESP32 sends digital signals to the relay (HIGH/LOW)
Relay switches the 12V power circuit on/off
This allows safe control of high-power devices with low-power microcontrollers

Important: If you're new to relays, check out our ESP32 C3 Super Mini - Relay tutorial first to understand pinout, wiring, and programming basics.

For the second way, the ESP32 C3 Super Mini - MOSFET Module tutorial explains the module's terminals and how PWM sets the power.

Relay vs MOSFET Module for a Heating Element

	Relay	MOSFET Module
Heater control	Full heat or no heat	Full heat, no heat, or any level between (PWM)
Sound	Clicks on every switch	Silent
Switching time	Milliseconds, mechanical	Almost instant
Long-term use	Contacts wear, worse with frequent switching	Nothing moves, nothing wears
Power type	AC or DC heaters	DC heaters only
Heater supply	Any voltage within the relay rating	6V or more
Isolation	Coil is separate from the contacts	PC817 optocoupler inside
Pick it when	The heater runs on AC, or you need only ON/OFF	A 12V DC heater that switches often or needs a set heat level

A thermostat turns the heater ON and OFF many times a day, so the MOSFET module is a good match for a 12V DC heating element. If your heater runs on AC mains, you must stay with the relay.

Wiring Diagram

Follow this wiring diagram to safely connect your ESP32 C3 Super Mini to the heating element via relay.

Please be careful. It can burn you and your house. This is a serious topic, and we want you to be safe. If you're NOT 100% sure what you are doing, do yourself a favor and don't touch anything. Ask someone who knows! We do NOT take any responsibility for your safety.

The wiring diagram between ESP32 C3 Super Mini Heating Element

This image is created using Fritzing. Click to enlarge image

Safety notes:

Double-check all connections before applying power
Never touch the heating element when powered on
Ensure proper ventilation during operation
Use appropriate wire gauge for 12V connections
Keep flammable materials away from the heating element

ESP32 C3 Super Mini Code

The following code demonstrates basic heating element control by turning it ON for five seconds, then OFF for five seconds in a repeating cycle.

What this code does:

Configures a digital pin to control the relay
Turns the heating element ON (5 seconds)
Turns the heating element OFF (5 seconds)
Repeats the cycle continuously
Provides a foundation for temperature control projects

Code Explanation

The above ESP32 C3 Super Mini code contains line-by-line explanation. Please read the comments in the code!

Detailed Instructions

New to ESP32 C3 Mini? Complete our Getting Started with ESP32 C3 Mini tutorial first to set up your development environment.
Connect hardware: Wire the ESP32 C3 Super Mini, relay, and heating element according to the wiring diagram above.
Plug in USB: Connect your ESP32 C3 Super Mini to your computer using the USB Type-C cable.
Open Arduino IDE: Launch the Arduino IDE software on your computer.
Select board: Choose the correct ESP32 C3 Super Mini board from the Tools menu.
Select port: Choose the COM port that your ESP32 is connected to.
Copy code: Copy the complete code from the code section above.
Paste code: Paste it into a new Arduino IDE sketch window.
Upload code: Click the Upload button and wait for the process to complete.
Test operation: Observe the heating element turning on and off every 5 seconds.
Check temperature: Carefully feel for heat (without touching) to verify operation.
Pro Tip: Start with short ON times while testing to verify your wiring is correct before running longer heating cycles.

ESP32 C3 Super Mini Code - Heating Element with MOSFET Module

This part uses the MOSFET module in place of the relay. With PWM on GPIO4, the heater gets only part of the 12V power, so you can choose how warm it gets.

MOSFET Module Wiring Diagram

The wiring diagram between ESP32 C3 Super Mini heating element MOSFET module

This image is created using Fritzing. Click to enlarge image

GPIO4 on the ESP32 C3 Super Mini → PWM on the module
GND on the ESP32 C3 Super Mini → GND on the module
12V adapter + and heater + → both into the module's + terminal
Heater − → module LOAD
12V adapter − → module −
No flyback diode is needed. A heating element is not a coil.

The same safety warning as above applies here. The heater gets hot even at low power.

Code

/* * This ESP32 C3 Super Mini code was developed by newbiely.com * * This ESP32 C3 Super Mini code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/esp32-c3/esp32-c3-super-mini-controls-heating-element */ const int MOSFET_PIN = 4; // ESP32 C3 Super Mini GPIO4 connected to the PWM pin of the MOSFET module void setup() { Serial.begin(9600); pinMode(MOSFET_PIN, OUTPUT); analogWrite(MOSFET_PIN, 0); // start with the load OFF } void setLoad(int percent) { int duty = map(percent, 0, 100, 0, 255); // convert 0-100% to 0-255 analogWrite(MOSFET_PIN, duty); Serial.print("Load power: "); Serial.print(percent); Serial.println("%"); } void loop() { // turn the load fully ON, then fully OFF Serial.println("Load: ON"); setLoad(100); delay(2000); Serial.println("Load: OFF"); setLoad(0); delay(2000); // increase the power step by step (PWM) for (int percent = 10; percent <= 100; percent += 10) { setLoad(percent); delay(500); } // decrease the power step by step (PWM) for (int percent = 90; percent >= 0; percent -= 10) { setLoad(percent); delay(500); } delay(1000); }

How the heater reacts to this code:

2 seconds at full power, then 2 seconds off
Then the power climbs from 10% to 100% and falls back to 0%, step by step
A heater warms up and cools down slowly. You will not feel each step at once; the change shows after a while. For a real test, set one fixed level and wait a few minutes

Detailed Instructions

Prepare Arduino IDE and select the board as in the relay Quick Steps above
Wire the heating element to the MOSFET module (see the list and diagram)
Paste the code into Arduino IDE and click Upload
Plug in the 12V adapter
Open the Serial Monitor at 9600 baud to see the power level

Newbiely | Arduino IDE 2.3.8

──

☐

Newbiely.ino

···

8 Serial.println("Hello World!");

Output

Serial Monitor

Message (Enter to send message to 'ESP32C3 Dev Module' on 'COM15')

New Line

9600 baud

Load: ON Load power: 100% Load: OFF Load power: 0% Load power: 10% Load power: 20% Load power: 30% Load power: 40% Load power: 50% Load power: 60% Load power: 70% Load power: 80% Load power: 90% Load power: 100% Load power: 90% Load power: 80% Load power: 70% Load power: 60% Load power: 50% Load power: 40% Load power: 30% Load power: 20% Load power: 10% Load power: 0%

Ln 11, Col 1

ESP32C3 Dev Module on COM15

Tip: give the module a heater supply of at least about 6V, and DC only. An AC heater needs the relay.

Application Ideas

Use this ESP32 heating element control setup as the foundation for various heating automation projects.

Build a simple thermostat-controlled heating system
Create a pet enclosure temperature regulator
Design a plant propagation warming mat controller
Make a DIY sous vide cooking temperature controller
Develop a small-scale incubator for hatching projects
Build a drying cabinet with automated heating cycles

Video Tutorial

Watch the video below for a visual walkthrough of this project.

...VIDEO /videos/tutorial/KITS_ESP_HEATING_ELEMENT.mp4

...VIDEO

Challenge Yourself

Take your ESP32 heating element skills to the next level with these progressive challenges.

Easy: Modify the code to change the ON/OFF time intervals to 10 seconds each.
Easy: Add a status LED that lights up when the heating element is active.
Medium: Integrate a temperature sensor (DS18B20) to display current temperature on Serial Monitor.
Medium: Create a simple thermostat that turns heating on when temperature drops below a set point.
Advanced: Build a PID temperature controller for precise heating control with minimal overshoot.

Learn More

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