Correct !
I’ve not had the chance to stop by the local RS for the LM339 but I did make this graphic, a cross of a schematic and layout diagram. It illustrates one thing that will be important in arranging the wiring, that is to keep the high resistance input wires separated from the output wires.
(click on to open)
FWIW I’m leaning towards getting rid of the “input resistors”, R9-R12. I’m not sure they are really needed. R1-R4 with C1-C4 determine how long the low “hit detected” pulse stays “low”. R5-R8 are pull-ups to detect an open connection btw the detectors and the piezos. D1-D4 prevent potential damage due to the negative going pulse from the piezo.
Got it. Is the separation of the lines because of the possibility of inductive interference?
Sorry I’ve been less active lately. I have some deadlines to meet and have caught a cold in the meantime. So my bandwidth has been somewhat reduced. I’ll have time to test a few things in the meantime but will get back on it hard next week.
Really, I am going to get back to this. Had to install a server in a local organization, and then a friend with a damaged hard drive. I am going to test the additional resistor on the old design and will get a few LM339’s ordered and start testing this design.