Now for something completely different

[Tramp]

Do you have to test with the meter in parallel or series? If its parrallel just put a variable resistor on the end of one of the test leads & start it on say 1 Meg ohm & turn it down until you get a reading on your scale! And to get an accurate graph use an oscilliscope, im sure your college will have one,

[Edweird]

Thanks Tramp, I think that's what I'll do if they let me.

[Edweird]

It's been a while since I've posted about this on the forum, kinda bumping an old thread here, but I've finally got my prototype rev counter working. I decided to use multiplexed 7 segment displays instead of the LED bar because it looks more retro and to do the LED bar I would need an unholy amount more components, (30 LEDs, two resistors for each, a comparator for each etc) and I want to keep the overall component count down so that the PCB I eventually get made for it will be fairly small so that it'll fit in a nice little box.

[turbo-tom]

lookig good ed looking good

[Edweird]

Thanks. I'm quite proud of it. The initial design used 4 different microchips, but with a little help from one of the teachers-in-training at college, we came up with a way to get a PIC chip to do the entire conversion from hertz to 7 seg display. And, it only takes about 20 microseconds longer for it to work out 22,500 rpm than it does 0 rpm, which is much better than my initial design. I've haven't added the digit for the tens of thousands to the display though, cause it wouldn't be worth it.

[ScottieJ]

sounds good, now where is a vid of it working

[Edweird]

I'll have to find something I can borrow from someone to video it with. My crappy old Nokia can't record videos that I can put on youtube or whatever.