This is a multi-part message in MIME format. --Boundary_(ID_W1fhrgqwGsmSxFwMbPfMhA) Content-type: text/plain; charset=us-ascii Content-transfer-encoding: 7BIT Picdude wrote: > - Take the signal off the negative of the ignition coil, and clean that up so > you get a good clean square wave suitable for input to a PIC. I'll stop > here, since this was the biggest pain ever... getting a clean square wave, > and I yet have to finish this part. I had found an Intersil part, HIP9020 > that seemed like it would've been ideal for this purpose, but Intersil > discontinued it at the beginning of this year. In the meanwhile, I have come > up with a circuit using a filter, op-amp, and some passives, but will try it > out after I get my test-car back. I can post if I get that working well. An > alternate way it to use an inductive pickup, which is "wrapped" around a > higher-voltage plug wire, and will have a small signal induced in it on each > pulse. Try attached GIF regards Tony -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu --Boundary_(ID_W1fhrgqwGsmSxFwMbPfMhA) Content-type: image/gif; name=TACH.GIF Content-disposition: inline; filename=TACH.GIF Content-transfer-encoding: base64 R0lGODdhnQEEAYMAAAAAAIAAAACAAICAAAAAgIAAgACAgICAgMDAwP8AAAD/AP//AAAA//8A /wD//////ywAAAAAnQEEAQAE/vDJSau9OOvNu/9gKI5kaZ5oqq5s675wLM90bd94ru987//A oHBILBqPyKRy+Tg8EAdnFAFgWq/G6PMAhTa72HDKKSFzq+K0+lZFeLcISXxN95CfZW19z0dx 42gPgX2EFmRzTwCIhYyNGIqCE4OOhFwHAFxlHACTlJ5DnBmHf1+Ln6cWnKGorD2qna2Ur7O0 tba3t7GouLy9vqu6p8DBxDPDxcgasMnMKMvNzLCXUVMU06bQzc/ZxbBUE1Rmedzc2+S63oPf eBLm56zu77sX65Kmd/Ld+dH0k5jW2Pa1iifQUboKkOQELDiPYbCD4AK9cYiOYkUL9aggurPQ IiOC/h73SMNEDdGskA1RfgKp8mHLlS/lsYyJZSZNYTfr/LKZkw/PnkF2AnU5VOTPon2OIgWC BmKiRRopSKwmh6rUpTqUYuUxCNagS4vwXapaJs6bTBPGbmWztmaqt2nBpgW3To8XuxzrtTW2 l8kyf9aaJLzjpOmcbwnrFe5LQytjGdu6BhYcR1wkQYerJEZDxvFjZZ+NuAv0VVIVJ27atcuM 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