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  1. #1
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    How to implement timer to read sensor signal periodically without MCU

    I would like to read the signal from a sensor periodically, for example 0.5Hz, but my circuit does not have a microcontroller.

    Firstly, I think that if I can implement a timer, like a 555timer, with some logic gates to read the signal from the sensor. However, when the timer is not enabling to read the sensor signal, the output of the circuit should be latch. I do not know how to implement this.

    The truth table:
    Click image for larger version. 

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ID:	154019


    Or is there other simpler method?

    Thank you very much.

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  2. #2
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    Re: How to implement timer to read sensor signal periodically without MCU

    Hi,

    Please be more specific.

    "A sensor" can be almost any device... with any interface you can think of...
    It can be:
    * a simple resistor ( as current sensor with voltage output)
    * a thermocouple (as temperature sensor with voltage output that needs additional circuitry)
    * a strain gauge (mechanic sensor with ratiometric output)
    * a digital temperature sensor with any kind if digital interface
    * a reed relay (as RPM sensor on a bicycle)
    * and thousands more

    "It has no microcontroller" ....why don't you say "what it has" instead?.
    So we have to guess. Does it has a:
    * analog voltage meter
    * a stepper motor driven gauge
    * digital 7 segment display
    * PLC
    * PC
    ...

    The first idea of a solution to your problem can be to use a ICL7107 (or similar) circuit.
    It includes anything from refrence voltage, input amplifier, ADC, decoder, timing generator, display encoder ... to display driver...

    Klaus
    Please don´t contact me via PM, because there is no time to respond to them. No friend requests. Thank you.



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  3. #3
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    Re: How to implement timer to read sensor signal periodically without MCU

    Your Truth Table looks like a D-Latch
    D-LATCH



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