Simulating Crankshaft Position Sensor Output

Discussion in 'The Projects Forum' started by Quinn McFaie, Feb 18, 2016.

  1. Quinn McFaie

    Thread Starter New Member

    Feb 18, 2016
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    I'm working on a Motor Grader Simulator without an engine. I'm trying to simulate a 72 tooth gear on a crankshaft with 2 teeth missing (marks top dead center for cylinder 1). I have a signal generator, but I am unable to turn it off for 2 cycles, so I wanted to create a circuit on a bread board to do it. I was thinking of using a 4017 (count to n and recycle) to count up to 72 to reset another 4017 (count to n and halt) that halts at 70, but the 4017 doesn't have an output that I can hook up to simulate the sensor. Is there a counter that has a single output that I can simulate the output of the sensor? Reference voltage on the sensor is 5 VDC and the ECU is looking for an return of .2 to .5 VDC - 4.5 to 4.8 VDC.
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,998
    745
    You can cascade them, the second chip is clocked from the Carry out pin 12 of the first chip, set the first chip to clock to 10, set the second chip to clock to 10, and use an "And"gate from the 2 count pin on the first chip, and 7 count pin on the second chip,(72) to reset both counters.

    Or use a Cd4040 binary counter chip and use the 8 and 64 pins to the" And gate" to reset it.
     
    Last edited: Feb 18, 2016
  3. Quinn McFaie

    Thread Starter New Member

    Feb 18, 2016
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    Thank you for the information, but I think this takes me right back to my first conundrum. I need a single output with the digital square wave that pulses for 70, skips two, and starts all over.
     
  4. Dodgydave

    Distinguished Member

    Jun 22, 2012
    4,998
    745
    OK, do you want a square wave pulse for 70 pulses, and nothing for two pulses, then repeat, if so you need a Nor gate, one input on the clocking pin on the first chip, and the other input to the 7 count on the second chip. This will give you 70 pulses from the output of the Nor gate, then stop at 70, your And gate will reset the chips at 72.
     
    Last edited: Feb 23, 2016
  5. Quinn McFaie

    Thread Starter New Member

    Feb 18, 2016
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    0
    Thank you! I'll give this a try and see what happens. I'll let you know.
     
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