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RPM counter with Blockly — Parallax Forums

RPM counter with Blockly

Hi, totally new to blockly. Trying to read RPM from a half hull senor which goes low twice in one revolution. Any help would be appreciated.


  • Francis BauerFrancis Bauer Posts: 235
    edited 2019-11-17 03:54
    It sounds like your sensor just puts out simple high/low pulses per revolution. If so, you could probably use one of the counters in a cog to detect the pulse transistions. What voltages are we talking about here 12v, 5v or 3.3v? You will probably need to use a resistor or a transistor or level shifter to condition the incoming signal to be appropriate for the input pin of the propeller board being used.
  • Yes you are correct, works with 5V. So assume count low pulse. Not sure about the code.
  • Will this work FQ = (count(2, 1000));
    499 x 89 - 6K
  • kwinnkwinn Posts: 8,692
    Will this work FQ = (count(2, 1000));

    It should, but if the RPM pulses go low twice per revolution then counting for 500mS should give you the RPM without any additional calculations.
  • Thanks that's a good idea
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