This component will show you how to use I2C module read external i2c sensor data, here we use BH1750 light sensor(GY-30 module).
BH1750 measurement mode:
one-time mode: bh1750 just measure only one time when receieved the one time measurement command, so you need to send this command when you want to get intensity value every time
continuous mode: bh1750 will measure continuously when receieved the continuously measurement command, so you just need to send this command once, and than call bh1750_get_data() to get intensity value repeatedly.
Bh1750 has different measurement time in different measurement mode, and also, measurement time can be changed by call bh1750_change_measure_time()