基于STC15系列单片机的数字指南针HMC5883L的测试程序，以C语言编写，注释非常清晰明了-Compass based STC15 MCU digital HMC5883L test program, written in C, comments are very clear

基于stc15单片机，利用温湿度传感器采集数据，在通过MQTT通信控制继电器从而控制开关(Based on stc15 MCU, data is collected by temperature and humidity sensors, and the switch is controlled through MQTT communication.)