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Arduino UNO Q

Arduino UNO Q - Control Heating Element

In this guide, you will learn how to control a heating element using a relay with Arduino UNO Q. The relay acts as a switch between the Arduino UNO Q MCU and the heating element's power supply.

Arduino UNO Q Controls Heating Element

WARNING

When working with heating elements, exercise extreme caution. Heating elements can become very hot and pose fire and burn hazards. Never leave a heating element unattended while powered.

When working on projects connected to main electricity, it is critical to have proper knowledge to avoid electric shock. If you are not completely sure about what you are doing, please seek help from someone experienced.

We recommend testing with a low-voltage DC heating element for safety.

Hardware Preparation

1×Arduino UNO Q
1×USB Cable for Arduino Uno Q
1×Relay
1×Heating Element
1×12V Power Adapter
1×DC Power Jack
1×Jumper Wires
1×Recommended: Screw Terminal Block Shield for Arduino Uno
1×Recommended: Sensors/Servo Expansion Shield for Arduino Uno
1×Recommended: Breadboard Shield for Arduino Uno
1×Recommended: Enclosure for Arduino Uno
1×Recommended: Prototyping Base Plate & Breadboard Kit for Arduino UNO

Or you can buy the following kits:

1×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

Pinout

Heating Element Pinout

A heating element typically has two wires:

  • Positive (+) wire (red): Connect to the positive of the DC power supply
  • Negative (−) wire (black): Connect to the GND of the DC power supply

How to Control Heating Element

When a 12V heating element is connected to a 12V power supply, it produces heat. To switch it on and off from the MCU, we use a relay between the Arduino UNO Q and the heating element. The Arduino UNO Q controls the heating element through the relay. If you are unfamiliar with how a relay works, see the Arduino UNO Q - Relay tutorial first.

Wiring Diagram

The wiring diagram between Arduino UNO Q Controls Heating Element

This image is created using Fritzing. Click to enlarge image

Connect the heating element through the relay's COM and NO terminals to the power supply. The relay IN pin connects to Arduino UNO Q MCU pin 9.

MCU Code

The Arduino UNO Q has two processors: the STM32 MCU (handles real-time hardware control) and the Qualcomm MPU (runs Debian Linux). In this section, only the STM32 MCU is programmed — the Linux side stays idle. A later section will show how both processors work together.

The code below turns the heating element on for 5 seconds and off for 5 seconds repeatedly:

/* * This Arduino UNO Q code was developed by newbiely.com * * This Arduino UNO Q code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-uno-q/arduino-uno-q-controls-heating-element */ #define RELAY_PIN 9 // The Arduino UNO Q pin connected to the IN pin of the relay (controls heating element) void setup() { pinMode(RELAY_PIN, OUTPUT); } void loop() { digitalWrite(RELAY_PIN, HIGH); // turn heating element on for 5 seconds delay(5000); digitalWrite(RELAY_PIN, LOW); // turn heating element off for 5 seconds delay(5000); }

Detailed Instructions

  • First time with Arduino UNO Q? Follow the Getting Started with Arduino UNO Q tutorial to get your development environment ready before proceeding.
  • Wire the components: Connect relay IN → pin 9, DC+ → 5V, DC- → GND. Connect the heating element through the relay to the power supply.
  • Connect: Plug the Arduino UNO Q into your computer with a USB-C cable.
  • Open Arduino App Lab: Launch Arduino App Lab and wait until it detects your Arduino UNO Q.
  • Create a new App: Click the Create New App button.
Create New App in Arduino App Lab on Arduino UNO Q
  • Give the App a name, for example: DIYables_Heater
  • Click Create to confirm.
  • You will see a set of folders and files generated inside your new App.
Arduino App Lab App folders and files on Arduino UNO Q
  • Find the sketch/sketch.ino file — this is where you will paste the MCU sketch.
  • Paste the sketch: Copy the MCU code above and paste it into the sketch file. Keep other files as default.
    • Install the library: Click the Add sketch library button (the open book icon with a + sign) in the left sidebar.
    Add sketch library in Arduino App Lab on Arduino UNO Q
    • Search for Arduino_RouterBridge created by Arduino and click the Install button.
    My Apps / DIYables Apps
    Run
    Bricks
    No bricks added...
    Sketch Libraries
    No sketch libra...
    Files
    python
    sketch
    .gitignore
    README.md
    app.yaml
    sketch.ino
    Add sketch library
    Arduino_RouterBridge
    Arduino_RouterBridge Arduino

    This library provides a simple RPC bridge for Arduino UNO Q boards, allowing communication between the board and other devices using MsgPack serialization.

    0.4.1
    Install
    More Info
    Newbiely (Arduin...
    System stats
    • Upload: Click the Run button in Arduino App Lab to compile and upload to the STM32.
    Click Run button in Arduino App Lab on Arduino UNO Q
    • Test: The heating element should turn on for 5 seconds and off for 5 seconds repeatedly.

    Linux + MCU Bridge Programming

    The Arduino UNO Q has two processors that work together: the MPU (Qualcomm, runs Debian Linux) and the MCU (STM32, runs Zephyr OS with your Arduino sketch). They communicate using RPC via the Arduino_RouterBridge library — never via raw serial ports.

    • The relay (and heating element) is connected to the MCU (STM32) — relay IN on pin 9.
    • The MPU cannot control the relay directly — it calls Bridge.call("heater_on") or Bridge.call("heater_off") on the MCU, which sets the relay pin.
    • The MPU has Wi-Fi — because the MPU runs full Debian Linux with Wi-Fi, it can accept Telegram commands to remotely control the heating element.
    • Communication: Bridge.call() on the Linux side invokes Bridge.provide_safe() on the MCU side (since digitalWrite() is used to control the relay)
    • ⚠️ Reserved: /dev/ttyHS1 (Linux) and Serial1 (MCU) are used by the Arduino Router — never open them directly

    In short: MPU sends heat command → MCU sets relay pin → heating element turns on or off.

    MCU sketch — heating element control with Bridge:

    /* * This Arduino UNO Q code was developed by newbiely.com * * This Arduino UNO Q code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-uno-q/arduino-uno-q-controls-heating-element */ #include "Arduino_RouterBridge.h" #define RELAY_PIN 9 void heater_on() { digitalWrite(RELAY_PIN, HIGH); Monitor.println("Heating element: ON"); } void heater_off() { digitalWrite(RELAY_PIN, LOW); Monitor.println("Heating element: OFF"); } void setup() { Bridge.begin(); Monitor.begin(); pinMode(RELAY_PIN, OUTPUT); digitalWrite(RELAY_PIN, LOW); Bridge.provide_safe("heater_on", heater_on); Bridge.provide_safe("heater_off", heater_off); Monitor.println("Heating Element Bridge ready"); } void loop() {}

    Python script (Arduino App Lab) — turn heating element on for 5 seconds, off for 5 seconds:

    /* * This Arduino UNO Q code was developed by newbiely.com * * This Arduino UNO Q code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-uno-q/arduino-uno-q-controls-heating-element */ from arduino.app_utils import * import time def loop(): Bridge.call("heater_on") time.sleep(5) Bridge.call("heater_off") time.sleep(5) App.run(user_loop=loop)
    • Note: Make sure Bridge.begin() is called in the MCU sketch and the sketch is uploaded before running the Python script on the Linux side.
    • ⚠️ Warning: Never directly open /dev/ttyHS1 (on Linux) or use Serial1 (on MCU) in your code — these are reserved by the Arduino Router and accessing them will break the Bridge.

    Detailed Instructions

    • Upload the MCU sketch: Open Arduino App Lab, create a new App, paste the Bridge MCU sketch into sketch/sketch.ino, install the Arduino_RouterBridge library, and click Run.
    • Add the Python script: Paste the Python code above into the Python tab of the same App.
    • Run the App: Click Run — Python turns the heating element on and off every 5 seconds.
    • Check the console: Open the Console tab → MCU Monitor subtab to see the heater state.

    App Lab Console Output

    DIYables_Apps
    Stop
    sketch.ino
    1#include "Arduino_RouterBridge.h"
    Serial Monitor
    Python
    Message (Enter to send a message to "Newbiely" on usb(2820070321))
    New Line
    9600 baud
    Heating Element Bridge ready Heating element: ON Heating element: OFF Heating element: ON Heating element: OFF
    Newbiely (Ardu...
    System stats
    DIYables_Apps
    Stop

    Telegram Integration

    Control the heating element remotely via Telegram with /on and /off commands.

    If you do not have a Telegram bot yet, see How to Create a Telegram Bot to get your bot token before continuing.

    MCU sketch: Keep the same MCU sketch from the previous Bridge section — no changes needed. Make sure it is already uploaded and running on the STM32 before proceeding.

    Python script (Arduino App Lab) — Telegram bot for heating element control:

    /* * This Arduino UNO Q code was developed by newbiely.com * * This Arduino UNO Q code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/arduino-uno-q/arduino-uno-q-controls-heating-element */ from arduino.app_utils import * import requests import time BOT_TOKEN = "YOUR_BOT_TOKEN" API_URL = f"https://api.telegram.org/bot{BOT_TOKEN}" last_update_id = 0 def send_message(chat_id, text): requests.post(f"{API_URL}/sendMessage", json={"chat_id": chat_id, "text": text}) def get_updates(): global last_update_id resp = requests.get(f"{API_URL}/getUpdates", params={"offset": last_update_id + 1, "timeout": 5}) return resp.json().get("result", []) def loop(): global last_update_id updates = get_updates() for update in updates: last_update_id = update["update_id"] msg = update.get("message", {}) chat_id = msg.get("chat", {}).get("id") text = msg.get("text", "").strip() if text == "/on": Bridge.call("heater_on") send_message(chat_id, "Heating element is ON.") elif text == "/off": Bridge.call("heater_off") send_message(chat_id, "Heating element is OFF.") else: send_message(chat_id, "Commands:\n/on — turn heating element on\n/off — turn heating element off") time.sleep(0.5) App.run(user_loop=loop)
    • Note: Replace YOUR_BOT_TOKEN with the token obtained from @BotFather on Telegram.
    • Send /on to activate the heating element; /off to deactivate it.

    Detailed Instructions

    • Upload the MCU sketch: Use the Bridge MCU sketch from the previous section (upload it first if not already done).
    • Paste the Telegram script: Copy the Python code above into the Python tab of your App in Arduino App Lab.
    • Set your token: Replace YOUR_BOT_TOKEN in the script with your actual bot token.
    • Run the App: Click Run — the bot starts listening for Telegram messages.
    • Test it: Send /on and /off to control the heating element.

    App Lab Console Output

    DIYables_Apps
    Stop
    sketch.ino
    1#include "Arduino_RouterBridge.h"
    Serial Monitor
    Python
    [2026-04-29 12:00:01] Telegram: /on [2026-04-29 12:00:01] Heating element is ON. [2026-04-29 12:05:30] Telegram: /off [2026-04-29 12:05:31] Heating element is OFF.
    Newbiely (Ardu...
    System stats
    DIYables_Apps
    Stop
    Telegram
    Telegram 12:45
    Welcome to Telegram!
    ArduinoBot 10:19
    Chatting with Arduino...
    telegram-botfather
    BotFather Yesterday
    Your bot has been created.

    ArduinoBot

    bot
    Today
    /on
    10:15 AM ✓✓
    Heating element is ON.
    10:16 AM
    /off
    10:17 AM ✓✓
    Heating element is OFF.
    10:18 AM

    OpenClaw Integration

    OpenClaw integration for Arduino UNO Q heating element control is coming soon.

    • Coming Soon: OpenClaw support for this project on Arduino UNO Q will be covered in a future update.

    Application/Project Ideas

    • Smart thermostat: Combine with a temperature sensor to automatically maintain a target temperature
    • Incubator control: Keep an egg incubator at a precise temperature using feedback control
    • Greenhouse heating: Automatically heat a greenhouse when the temperature drops below a set point
    • Remote heater: Turn a space heater on before arriving home using Telegram

    Challenge Yourself

    • Easy: Change the on/off interval from 5 seconds to 30 seconds
    • Medium: Add a /toggle command that switches the heating element to the opposite state
    • Advanced: Combine with a temperature sensor — automatically turn the heater on when below threshold and off when above

    Function References

    Learn More

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