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Topic: Need ideas on tachometer using ignition (Read 4 times) previous topic - next topic

afremont

A common phototransistor could easily measure well over 100K pulses per second.  If you go with an inductive pickup, I'd put a 47K resistor in line and a 5.1V zener diode (between resistor and arduino) as a shunt to ground to protect the arduino.  You will find that the electrical supply in a car is the worst as far as spikes, sags and voltage dumps go.  Prepare to harden your designs.
Experience, it's what you get when you were expecting something else.

M4vrick

Hi :)

I'll follow your topic, I have something like you but my actual missing point is the frequency measurement with the arduino.

Grumpy_Mike


but my actual missing point is the frequency measurement with the arduino.

Simply google arduino frequency measurement
Basically you time the interval between two successive pulses and take the reciprocal of it.

M4vrick


Simply google arduino frequency measurement
Basically you time the interval between two successive pulses and take the reciprocal of it.


I've tried today 3 differents library without having a clear frequency measure. My car got a connector to have an external tachometer so I assume the input signal is in good shape, but I'll check with a friend and an oscilloscope to be sure.

I'm not good enough to code the measurement by myself  :*

GoForSmoke

It's not rocket science.
Step 1) Learn Blink Without Delay. Really learn how it works.
Step 2) if you learned in step 1 then you probably know what to do.

I find it harder to express logic in English than in Code.
Sometimes an example says more than many times as many words.

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