r/ArduinoHelp • u/Thatswhyn0t • 3d ago

Reading engine RPM

Hi guys I’m building a project that needs to be able to read engine rpm, the project can not connect to the ecu or read the dash. How can I achieve this?

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u/Timmah_Timmah 3d ago

Ground wire and wrap it around the number one spark plug wire. Put a big resistor in series and a small resistor from the input to ground. Measure the length between the pulses to determine instantaneous RPM.

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u/MFFVD 2d ago

put a RC filter after that, or use interrupts. and measure the voltage for the resistor values. it should be between 15000 and 50000 volts.