BBQ & Oven Thermometer

Overview

A type-K thermocouple handles oven and grill temperatures that would destroy ordinary probes. The ET-S19 reads it with 19-bit resolution, cold-junction compensation and fault detection, so you know if the probe is unplugged or shorted.

The ET-S22 infrared thermometer reads the grill plate or pizza stone without touching it. A buzzer sounds when the meat reaches your target temperature.

• Thermocouple probe up to 1,000 °C+ (probe-dependent)
• Non-contact surface temperature
• Open-probe and short-circuit fault detection
• Target-temperature buzzer

What you need

ElectroTrical boards

ET-S19MAX31856 Thermocouple AmplifierMAX31856 thermocouple amplifier (SPI)

AED 59.00Out of stock

ET-S22MLX90614 IR ThermometerMLX90614 non-contact IR thermometer (I²C)

AED 49.00Out of stock

Boards total: AED 108.00

These boards are being manufactured. Open a board's page to see when it's back, or ask us about a kit.

You'll also need

• ESP32-S3 DevKitC-1 (or any ESP32-S3 board) with a USB-C data cable. Not sold by ElectroTrical.
• Type-K food-grade thermocouple probe (stainless, with miniature connector or bare wires)
• Active 3.3 V buzzer
• Jumper wires

Wiring

Type-K colours: in the IEC standard + is green and − is white; in the US standard + is yellow and − is red. If the temperature falls when you heat the probe, swap the two wires.

Build it

1. 01

   Set up the Arduino IDE

   Install Arduino IDE 2, add the Espressif ESP32 board package (Boards Manager → “esp32” by Espressif), select “ESP32S3 Dev Module” and turn on USB CDC On Boot so Serial prints over USB. Install the libraries listed above the sketch from Library Manager.

2. 02

   Check at room and boiling temperature

   With the probe in air it should read room temperature. In boiling water it should read about 100 °C.

3. 03

   Set the target

   Change TARGET_C in the sketch — for example 63 °C for medium-rare beef or 74 °C for chicken.

4. 04

   Aim the IR sensor

   The MLX90614 averages a wide cone (about 90°). Hold it 2–5 cm above the surface you want to measure, and keep the board itself out of the heat.

Arduino code

Written for the ESP32-S3 DevKitC-1 with the Espressif Arduino core. Install these libraries from the Arduino Library Manager:

• Adafruit MAX31856 library
• Adafruit MLX90614 Library

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_MAX31856.h>
#include <Adafruit_MLX90614.h>

const int   CS_PIN = 10;
const int   BUZZER_PIN = 7;
const float TARGET_C = 63.0;

Adafruit_MAX31856 tc(CS_PIN);
Adafruit_MLX90614 ir;

void setup() {
  Serial.begin(115200);
  pinMode(BUZZER_PIN, OUTPUT);

  SPI.begin(12, 13, 11, CS_PIN);    // SCK, MISO, MOSI, CS
  if (!tc.begin()) Serial.println("MAX31856 not found");
  tc.setThermocoupleType(MAX31856_TCTYPE_K);
  tc.setConversionMode(MAX31856_CONTINUOUS);

  Wire.begin(8, 9);
  if (!ir.begin()) Serial.println("MLX90614 not found (0x5A)");
}

void loop() {
  float probe = tc.readThermocoupleTemperature();
  uint8_t fault = tc.readFault();
  float surface = ir.readObjectTempC();

  if (fault & MAX31856_FAULT_OPEN) {
    Serial.println("Probe not connected");
  } else if (fault) {
    Serial.printf("Thermocouple fault 0x%02X\n", fault);
  } else {
    Serial.printf("Probe %.1f C | Surface %.1f C\n", probe, surface);
  }

  bool done = !fault && probe >= TARGET_C;
  digitalWrite(BUZZER_PIN, done && (millis() / 500) % 2);   // beep
  delay(500);
}

Troubleshooting

Take it further

• Show both temperatures on a phone page over Wi-Fi
• Add a second ET-S19 for a second probe (separate CS pin)
• Drive a fan on a MOSFET board to control charcoal temperature