R6,R7,D7 together detect FS1 blown. Detect incoming AC pulse in software.
Remaining components detect Loading. Designed for 40W approx. Change R2 to suit your application to give you less than 1v at your desired load. Use ADC or Comparator to measure if device is ON, OFF or sideways. Do not design above 2v input to PIC as protection Zener will start to conduct and distort measurement.
Caution, PICs 0v rail is common with supply Neutral.
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