geliang201201/esp8266_htu21d

ESP8266 Driver for Measurement Specialties HTU21D i2c Temperature and Relative Humidity Sensor

ESP8266 HTU21D Driver

Driver Library for the Measurement Specialties HTU21D temperature & humidity sensor.

The HTU21D is an i2c device with a temperature sensing element (capable of 14bit resolution or 0.01 degC) and a relative humidity sensing element (capable of 12bit resolution or 0.04%RH).

Sensirion SHT21 appears to be code compatible, but is currently untested.

Usage

In user_init call:

i2c_init();

To read temperature run HTU21D_temperature(&temperature); where temperature is an existing float variable.

To read humidity run HTU21D_humidity(&humidity); where humidity is an existing float variable.

Both functions return integer 1 on success, or integer 0 on failure.

See Example_user_main.c for typical usage. Actual usage is shown within IdleTask function.

Note: ftos() function is provided to convert a float into a text string for use with os_printf

See i2c.h to set the GPIO pins for i2c. Default is SCK = GPIO0, SDA = GPIO2. (you may need to change this depending on your board configuration)