Temeperture alarm system. This project has developed with CCS PIC C complier. Receiver and transmitter can communicate with PWM modulation to 1 km until. You can adjust alarm trigger on lcd display.

Source fot test pwm on pic of microchip

PIC芯片，具有采样，PWM，NTC温度，PID控制，MPPT功能(PIC chip, with sampling, PWM, NTC temperature, PID control, MPPT functions)