ok, i have a jeep with a manual transmsison and it doesnt have a tach, would it be possible to create one using like a LED bar-graph i am sure zappy has some insight on this.
I did a digital tacho for my Alevel project (worked too ) its not too tricky. Mine had 2 7-segment LED readouts, too get a bargraph you'd have to use D-A conversion and a driver. The basic layout was 2 cascaded counters, driven by the points, and a 555 to trigger a latch and reset the counters, so the latch would store the pulses in a time period. The time period was 'fiddled' to give the thousands and hundreds of RPM out on the counters. Then the latches drove the leds, or a D to A convertor in your case. Ive seen threads about fan speed sensing which is basically the same thing
Try this I'm quite sure there are kits around in your country's friendly electronic store. I'm interested to make one (instead of buying it) coz most of these tap the signal from the distributor (If I'm not wrong). I would prefer to tap the signal from my ECU. Let us know how it goes! Cheers.
There are many products out there, (as posted aboce) Or you could try searching google. http://www.google.com/search?hl=en&...off&q=tachometer+schematic&btnG=Google+Search (I would help more but I am pretty busy right now)
Velleman do a kit that gives you a four digit 7-segment LED display readout. It's sold by Maplins in the UK. MoJo
