Arduino UNO Q - MAX6675 Thermocouple Module
Regular sensors like the DHT11 or LM35 can't survive being near an oven, a soldering iron, or a running engine — they simply weren't built for that kind of heat. The MAX6675 module solves this by pairing a Type-K thermocouple probe with a dedicated digitizer chip, letting your Arduino UNO Q safely read temperatures far beyond what a normal sensor could handle. This tutorial shows you how to wire and program it — and monitor it remotely via Telegram.
In this tutorial, you will learn:
- What the MAX6675 thermocouple module is and how it works
- How to wire the MAX6675 module to the Arduino UNO Q MCU
- How to program the MCU (C/C++ Arduino code) to read temperature from the MAX6675
- How to program both the Linux side (Python) and MCU side (C/C++) to read MAX6675 data via Bridge
- How to receive Telegram alerts when temperature exceeds a threshold on Arduino UNO Q
- How to use OpenClaw on Arduino UNO Q with the MAX6675 module
Hardware Preparation
Or you can buy the following kits:
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
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Additionally, some of these links are for products from our own brand, DIYables .
Additionally, some of these links are for products from our own brand, DIYables .
Overview of the MAX6675 Thermocouple Module
A thermocouple is a temperature sensor made of two different metal wires joined together at one end, called the hot junction. Heating that junction produces a tiny voltage that changes with temperature — the MAX6675 chip converts this tiny voltage into a clean 12-bit digital reading your Arduino UNO Q can use directly. The most common probe type, Type-K, is made of Chromel and Alumel wires and can measure roughly -328°F to +2300°F.
| MAX6675 Module | |
|---|---|
| Operating Voltage | 3.0V to 5.5V |
| Interface | 3-wire (SCK, CS, SO) |
| Temperature Range | 0°C to 1024°C (probe rated 0°C to 80°C on the outside casing) |
| Accuracy | ±3°C |
Pinout
The breakout board has four header pins and a 2-pin screw terminal for the probe:
- VCC: Connect to 3.3V or 5V
- GND: Connect to GND (0V)
- SCK: Clock pin — connect to a digital pin on the MCU
- CS: Chip select pin — connect to a digital pin on the MCU
- SO: Serial data output (MISO only, there is no MOSI) — connect to a digital pin on the MCU
The Type-K probe connects to the screw terminal on the other side of the board: red wire to +, blue wire to -.
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
| MAX6675 Module Pin | Arduino UNO Q MCU |
|---|---|
| VCC | 5V |
| GND | GND |
| SCK | D5 |
| CS | D4 |
| SO | D3 |
How To Program For MAX6675
- Include the library:
#include "max6675.h"
- Define the pins and create a thermocouple object:
#define SCK_PIN 5
#define CS_PIN 4
#define SO_PIN 3
MAX6675 thermocouple(SCK_PIN, CS_PIN, SO_PIN);
- Read the temperature in Celsius and Fahrenheit:
float tempC = thermocouple.readCelsius();
float tempF = thermocouple.readFahrenheit();
※ NOTE THAT:
The MAX6675 needs about 220ms to complete a conversion — avoid reading it more often than roughly once every 250ms.
Arduino UNO Q Code
The Arduino UNO Q has two processors working together:
- The STM32 MCU reads the MAX6675 module directly via its 3-wire interface — all sensor reading runs on the MCU
- The Qualcomm MPU runs Debian Linux and handles Wi-Fi, Python, and cloud connectivity
- In this section, only the MCU is programmed — the Linux side stays idle. A later section shows how both processors work together via Bridge.
The MCU reads the MAX6675 every second and prints the temperature to the Serial Monitor.
/*
* 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-max6675-thermocouple-module
*/
#include "max6675.h"
// Arduino UNO Q MCU pins connected to the MAX6675 module
#define SCK_PIN 5
#define CS_PIN 4
#define SO_PIN 3
MAX6675 thermocouple(SCK_PIN, CS_PIN, SO_PIN);
void setup() {
Serial.begin(115200);
delay(1500);
Serial.println("Arduino UNO Q MAX6675 Thermocouple Module ready");
}
void loop() {
float tempC = thermocouple.readCelsius();
float tempF = thermocouple.readFahrenheit();
Serial.print("Temperature: ");
Serial.print(tempC);
Serial.print("°C = ");
Serial.print(tempF);
Serial.println("°F");
delay(1000);
}
Detailed Instructions
First time with Arduino UNO Q? Follow the Getting Started with Arduino UNO Q tutorial before proceeding.
- Connect: Wire the MAX6675 module to the Arduino UNO Q MCU as shown in the wiring diagram.
- 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.
- Give the App a name, for example: Max6675ThermocoupleModule
- Click Create to confirm.
- Paste the sketch: Copy the MCU code above and paste it into sketch/sketch.ino. 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.
- Search for MAX6675 library created by Adafruit and click the Install button.
Bricks
No bricks added...
Sketch Libraries
No sketch libra...
Files
python
sketch
.gitignore
README.md
app.yaml
sketch.ino
- Upload: Click the Run button in Arduino App Lab.
- Touch the probe tip to something warm (a mug of hot water works well) — watch the temperature rise in the console.
App Lab Console Output
sketch.ino
1#include "Arduino_RouterBridge.h"
Serial Monitor
Python
[2026-04-29 09:00:01] Arduino UNO Q MAX6675 Thermocouple Module ready
[2026-04-29 09:00:02] Temperature: 24.50°C = 76.10°F
[2026-04-29 09:00:03] Temperature: 26.75°C = 80.15°F
[2026-04-29 09:00:04] Temperature: 31.00°C = 87.80°F
[2026-04-29 09:00:05] Temperature: 38.25°C = 100.85°F
Bridge: Linux + MCU
This section shows how to program both processors of the Arduino UNO Q so the Linux side can read MAX6675 temperature via Bridge:
- The MAX6675 module is connected to the MCU (STM32) via its 3-wire interface — the MCU reads and caches the latest values every second
- The MPU cannot access the MAX6675 directly — it must call Bridge functions to retrieve readings
- The MPU has Wi-Fi — running full Debian Linux, it can log data, publish to dashboards, or send alerts over the Internet
- Arduino_RouterBridge enables RPC communication between the two processors
- ⚠️ /dev/ttyHS1 (Linux) and Serial1 (MCU) are RESERVED by the router — never open them in user code
In short: MCU reads the MAX6675 every second and caches the result → MPU polls Bridge to retrieve readings → MPU publishes or alerts over Wi-Fi.
MCU Code (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-max6675-thermocouple-module
*/
#include "Arduino_RouterBridge.h"
#include "max6675.h"
// Arduino UNO Q MCU pins connected to the MAX6675 module
#define SCK_PIN 5
#define CS_PIN 4
#define SO_PIN 3
MAX6675 thermocouple(SCK_PIN, CS_PIN, SO_PIN);
float last_temp_c = 0.0;
float last_temp_f = 0.0;
unsigned long last_read_ms = 0;
void read_thermocouple() {
last_temp_c = thermocouple.readCelsius();
last_temp_f = thermocouple.readFahrenheit();
}
String get_temp_c(String arg) {
return String(last_temp_c, 2);
}
String get_temp_f(String arg) {
return String(last_temp_f, 2);
}
String get_status(String arg) {
return "Temp: " + String(last_temp_c, 2) + "°C / " + String(last_temp_f, 2) + "°F";
}
void setup() {
Bridge.begin();
Monitor.begin();
read_thermocouple();
Bridge.provide("get_temp_c", get_temp_c);
Bridge.provide("get_temp_f", get_temp_f);
Bridge.provide("get_status", get_status);
Monitor.println("Arduino UNO Q MAX6675 Thermocouple Module Bridge ready");
}
void loop() {
unsigned long now = millis();
if (now - last_read_ms >= 1000) {
last_read_ms = now;
read_thermocouple();
Monitor.println("Temp: " + String(last_temp_c, 2) + "°C / " + String(last_temp_f, 2) + "°F");
}
}
Python Code (Bridge)
"""
This Arduino UNO Q script was developed by newbiely.com
This Arduino UNO Q script 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-max6675-thermocouple-module
"""
from arduino.app_utils import *
import time
def loop():
temp_c = Bridge.call("get_temp_c")
temp_f = Bridge.call("get_temp_f")
print(f"Temperature: {temp_c}°C = {temp_f}°F")
time.sleep(1)
App.run(user_loop=loop)
Detailed Instructions
- Connect: Wire the MAX6675 module to the Arduino UNO Q as shown in the wiring diagram.
- Open Arduino App Lab: Launch Arduino App Lab and wait for the board to be detected.
- Create a new App: Click Create New App, name it Max6675ThermocoupleModuleBridge, then click Create.
- Paste the MCU sketch: Copy the MCU Bridge code above and paste it into sketch/sketch.ino.
- Paste the Python code: Copy the Python Bridge code above and paste it into the Python file in the App.
- Install the library: Click the Add sketch library button (the open book icon with a + sign) in the left sidebar.
- Search for Arduino_RouterBridge created by Arduino and click the Install button.
Bricks
No bricks added...
Sketch Libraries
No sketch libra...
Files
python
sketch
.gitignore
README.md
app.yaml
sketch.ino
- Upload: Click the Run button in Arduino App Lab.
- Watch temperature readings appear in the Python console every second.
App Lab Console Output
sketch.ino
1#include "Arduino_RouterBridge.h"
Serial Monitor
Python
[2026-04-29 09:00:01] Arduino UNO Q MAX6675 Thermocouple Module Bridge ready
[2026-04-29 09:00:02] Temp: 24.50°C / 76.10°F
[2026-04-29 09:00:03] Temp: 26.75°C / 80.15°F
[2026-04-29 09:00:04] Temp: 31.00°C / 87.80°F
sketch.ino
1#include "Arduino_RouterBridge.h"
Serial Monitor
Python
[2026-04-29 09:00:02] Temperature: 24.50°C = 76.10°F
[2026-04-29 09:00:03] Temperature: 26.75°C = 80.15°F
[2026-04-29 09:00:04] Temperature: 31.00°C = 87.80°F
[2026-04-29 09:00:05] Temperature: 38.25°C = 100.85°F
Telegram
Monitor MAX6675 temperature remotely and receive automatic Telegram alerts when temperature rises above 100°C — handy for keeping an eye on an oven, a kiln, or a soldering station from another room.
MCU sketch: Keep the same MCU sketch from the previous Bridge section.
Python Code (Telegram)
"""
This Arduino UNO Q script was developed by newbiely.com
This Arduino UNO Q script 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-max6675-thermocouple-module
"""
from arduino.app_utils import *
import requests
import time
TELEGRAM_BOT_TOKEN = "YOUR_TELEGRAM_BOT_TOKEN"
CHAT_ID = "YOUR_CHAT_ID"
last_update_id = 0
ALERT_THRESHOLD_C = 100.0
alert_sent = False
def get_updates():
global last_update_id
url = f"https://api.telegram.org/bot{TELEGRAM_BOT_TOKEN}/getUpdates"
params = {"offset": last_update_id + 1, "timeout": 5}
try:
response = requests.get(url, params=params, timeout=10)
data = response.json()
if data["ok"]:
return data["result"]
except Exception as e:
print(f"Error getting updates: {e}")
return []
def send_message(chat_id, text):
url = f"https://api.telegram.org/bot{TELEGRAM_BOT_TOKEN}/sendMessage"
payload = {"chat_id": chat_id, "text": text}
try:
requests.post(url, data=payload, timeout=10)
except Exception as e:
print(f"Error sending message: {e}")
def loop():
global alert_sent
# Auto-alert on high temperature
temp_c_str = Bridge.call("get_temp_c")
try:
temp_c = float(temp_c_str)
if temp_c > ALERT_THRESHOLD_C and not alert_sent:
alert_sent = True
temp_f = Bridge.call("get_temp_f")
msg = f"🔥 High temperature alert: {temp_c_str}°C / {temp_f}°F"
print(msg)
send_message(CHAT_ID, msg)
elif temp_c <= ALERT_THRESHOLD_C:
alert_sent = False
except ValueError:
pass
# Handle Telegram commands
updates = get_updates()
for update in updates:
last_update_id = update["update_id"]
if "message" not in update:
continue
message = update["message"]
chat_id = message["chat"]["id"]
text = message.get("text", "").strip()
print(f"Received: {text}")
if text == "/start":
send_message(chat_id,
"Arduino UNO Q MAX6675 Thermocouple Bot\n"
"/temp - Read temperature (°C and °F)\n"
"/tempC - Read temperature in Celsius\n"
"/tempF - Read temperature in Fahrenheit\n"
"/status - Get sensor status")
elif text == "/temp":
temp_c = Bridge.call("get_temp_c")
temp_f = Bridge.call("get_temp_f")
send_message(chat_id, f"Temperature: {temp_c}°C = {temp_f}°F")
elif text == "/tempC":
result = Bridge.call("get_temp_c")
send_message(chat_id, f"Temperature: {result}°C")
elif text == "/tempF":
result = Bridge.call("get_temp_f")
send_message(chat_id, f"Temperature: {result}°F")
elif text == "/status":
result = Bridge.call("get_status")
send_message(chat_id, result)
else:
send_message(chat_id, "Unknown command. Send /start for help.")
time.sleep(1)
App.run(user_loop=loop)
Detailed Instructions
- Replace YOUR_TELEGRAM_BOT_TOKEN with your actual bot token from BotFather.
- Replace YOUR_CHAT_ID with your Telegram chat ID.
- Paste this Python code into your App's Python file (keep the same MCU sketch).
- Click the Run button. Send /temp from Telegram, or heat the probe past 100°C to trigger the alert.
App Lab Console Output
sketch.ino
1#include "Arduino_RouterBridge.h"
Serial Monitor
Python
[2026-04-29 09:10:00] Waiting for Telegram messages...
[2026-04-29 09:10:15] 🔥 High temperature alert: 104.50°C / 220.10°F
[2026-04-29 09:10:30] Received: /temp
[2026-04-29 09:10:45] Received: /tempC
Telegram
12:45
Welcome to Telegram!
ArduinoBot
10:19
Chatting with Arduino...
BotFather
Yesterday
Your bot has been created.
ArduinoBot
bot
OpenClaw
You can adapt the OpenClaw to this tutorial by refering the instruction on Arduino Uno Q - OpenClaw Tutorial
Project Ideas
You can build many useful projects with the MAX6675 and Arduino UNO Q:
- Kiln or Oven Temperature Logger: Log temperature over time via Bridge and Python, and plot the firing/baking curve on a dashboard
- Soldering Station Monitor: Track tip temperature and get a Telegram alert if it drifts outside your target range
- BBQ / Smoker Thermometer: Clip the probe to your grill grate and get remote Telegram updates so you don't have to keep opening the lid
- 3D Printer Hot End Watchdog: Use the MCU to trigger a relay via Bridge that cuts power if the hot end overheats beyond a safe limit
- Multi-Zone Furnace Survey: Connect multiple MAX6675 modules to different digital pins and have the Python side poll each one via Bridge for a side-by-side comparison
Challenge Yourself
Ready to go further with the MAX6675 on Arduino UNO Q? Try these challenges:
- Easy: Add a minimum/maximum tracker in the MCU sketch that remembers the highest and lowest temperature seen since boot.
- Medium: Add a get_fault(String) Bridge function that reports whether the thermocouple probe is disconnected (the MAX6675 sets a fault bit when the probe is open), and have the Python side print a warning if it's ever true.
- Advanced: Build a data logger: have the Python side write a timestamped CSV of temperature readings every 5 seconds, then add a Telegram /report command that sends back the highest reading from the last hour.