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Thread: Freq measure , 2 signals on one board ?

  1. #1
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    Freq measure , 2 signals on one board ?

    Im using freq measure to measure rpm in a car and am getting great results but now i also need to measure road speed which will also need freq measure but im not sure how to go about this ? Im using a uno board but have some teensie 3.1 there if they would be more suitable .Any help would be appreciated , Thanks

  2. #2
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    road speed from OBD plug's info? I'd think RPM is there too - maybe that's what you're using now!
    Or GPS though it's not as accurate or consistent (tunnels, etc.)

    There a speed sensor signal from modern transmissions.
    There's old school: glue a small magnet to driveshaft and use a hall effect sensor.

  3. #3
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    Unfortunately on this car there is no obd plug and what im after is a accurate quick signal for each , Theres no problem getting the signals or getting freq measure to read them its just im not sure how to measure both signals at the same time on one board .

  4. #4
    Senior Member Constantin's Avatar
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    Quote Originally Posted by 100 View Post
    Unfortunately on this car there is no obd plug and what im after is a accurate quick signal for each , Theres no problem getting the signals or getting freq measure to read them its just im not sure how to measure both signals at the same time on one board .
    I'd consider something simple like two interrupts on rising signals that increment the counter for each channel.

    Every time the RTC_TSR turns over one tick, export both counters, log, reset the counters, and start over.

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