Date: Thu, 20 Oct 2016 16:33:55 +0000 From: "Van Horn, David" > The three switches I do have, have pull resistors that are activated just= before reading, and a series resistor between the switch and the micro for= ESD. A small capacitor at the micro pin smooths the input, and that ESD = resistor also limits current between the cap and switch, keeping me from ev= er exceeding the switch current rating. So you disable the PIC's internal weak pull-ups, set your input pins to out= puts, then just before you read the input pins, you enable the internal pul= l-ups and then change them from outputs to inputs, then wait some time (1us= ?) for things to settle, then read. That works for ports that have interna= l pull-ups, but for designs with many switches, you may need to have inputs= on a port that lacks internal pull-ups, which means you would need to trea= t them differently. What value is your series resistor? 100ohms? It seems you put the capacitor (to ground) after the resistor, between the = input pin and resistor to make a first order LP RC filter. What value is y= our capacitance? I must say, zapping your circuit boards with a Tesla coil is fascinating. = I'd love to see a YouTube video of that in action! :-) James W. --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .