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simulate two variable frequency signals — Parallax Forums

simulate two variable frequency signals

Aaron WallAaron Wall Posts: 31
edited 2007-11-22 00:51 in BASIC Stamp
Hey Community,
I am trying to simulate two variable frequency signals to be interpreted by a module. What I am looking for is basically a PWMPal, but frequency instead of PWM.
I need the signals to be constantly transmitting. Then change frequency when commanded to by a Basic Stamp.

Any one have any ideas?

Comments

  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2007-11-20 22:22
    It would be helpful for anyone who might know the answer if you were to provide the required frequency range(s).

    -Phil
  • steve_bsteve_b Posts: 1,563
    edited 2007-11-21 20:26
    There are voltage to frequency modules....you might look at sending a PWM signal to them in order to fool them into working how you like.

    A PWM signal of 5volts and a duty cycle of 50% will look like 2.5Volts on a regular RMS meter.... (is this a fair statement to make folks? I'm sure there's a formula I don't remember for this).
    A duty cycle of 75% would give 3.75Volts..etc...

    cache.national.com/ds/LM/LM2907.pdf is a link to a freq to voltage IC.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    <FONT>Steve



    What's the best thing to do in a lightning storm? "take a one iron out the bag and hold it straight up above your head, even God cant hit a one iron!"
    Lee Travino after the second time being hit by lightning!
  • Aaron WallAaron Wall Posts: 31
    edited 2007-11-22 00:33
    I am looking to simulate sensor signals from a motorcycle.

    the Frequency of the RPM signal would be RPM/60, so a range of 13 Hz to 233 Hz

    the frequency of the wheel speed (hall effect) would be less than one hz at the slow end and up to 23 hz at the the fastest.

    One of my big questions has been weather this system I"m looking to fool reads it's sensors by measuring on time or frequency. The product is still on order, so I don't have it in hand yet to test. Looking at what the wheel speed signals would be if it measured frequency, I'm tinking that it would make more sense that the system looks at signal on time.
  • Aaron WallAaron Wall Posts: 31
    edited 2007-11-22 00:51
    Ok, so I was looking over the details of the PWMPal and it looks like that will cover all my needs. It allows for any duty cycle generation and frequencies from .3Hz to 20kHz. I can't think of any conditions that the rpm signal or speed signal could create that the PWMPal couldn't simulate.
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