AC Measurement

[mister_e]

<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=1185&stc=1&d=116343790 0">

On a PIC with ADC and comparator on the same pin it could be possible.

Comparator interrupt to detect the zero crossing, you wait 'till 0.707 Vpeak - x offset delay, then take an ADC reading.

OR use 2 I/o, one INT (let's say INT0) + ADC.

But i think the poor psu may suffer if you need many mA.... Could be handy to use high efficiency LED display.

EDIT: another maths approach using samplings... process the long RootMeanSquare stuff... or by 0.707*Vpeak.