Posted: Thu Jun 26, 2014 9:59 pm Post subject: Tacho
Hi
has someone made a tachometer with 1 rpm resolution and can give me som hints on how this can be done.
Let say we have an engine with a sensor that give us one puls pr. revolution.
If i calculate the frequency i can get more than 60rpm resolution.
Am not asking for someone to make the code for me, just a formula or some basics.
Joined: 16 Jan 2006 Posts: 2483 Location: Queensland
Posted: Fri Jun 27, 2014 3:52 am Post subject:
AN 138 seems remarkably complicated.
With 1 pulse per rev, just measure the time between pulses using a high speed timer, like eg timer1. The timer input capture function works well for this. Set the prescaler to give a count which does not overflow at the lowest possible engine speed.
Then the rpm is just 60,000,000/timer count, if the count is in microsec. Scaling the count to the actual clock frequency and divider used is pretty obvious. _________________ Adrian Jansen
Computer language is a framework for creativity
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