TempSensorI2C is a working example of how to use the I2C protocol to capture temperature readings from an Analog Device ADT7410 high-resolution temperature sensor and stream them to HomeKit. Built using the HomeSpan HomeKit Library, TempSensorI2C is designed to run on an ESP32 device as an Arduino sketch.
Hardware used for this project:
- An ESP32 board, such as the Adafruit HUZZAH32 – ESP32 Feather Board
- An Analog Device ADT7410 Temperature Sensor, such as the Adafruit ADT7410 Breakout Board
This simple HomeSpan sketch illustrates how the standard Arduino I2C library Wire.h can be used to capture temperature readings from an ADT7410 temperature sensor and stream them to HomeKit. The sketch:
- implements a single HomeKit Accessory containing a HomeKit TemperatureSensor Service;
- captures samples from the ADT7410 every 5 seconds;
- sends updates to HomeKit only if the temperature has changed by more than 0.5 Celsius; and
- is easily modified to accomodate up to 4 ADT7410 sensors, each with their own unique I2C address.
The connections below provide for I2C communicaiton between the ESP32 and the ADT7410 using the 7410's default address of 0x48:
| ADT7410 | ESP32 |
|---|---|
| VIN | 3V |
| GND | GND |
| SDA | SDA |
| SCL | SCL |
| A0 | unused |
| A1 | unused |
| INT | unused |
| CT | unused |
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