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nooby needing a sketch to simulate action of a pot

coldfire0101

hi to all

 

ive just started venturing into arduino land for various projects that keep springing to mind. i seemed to have hit a road block which maybe simple for some people here or ive just overlooked the obvious. i need to simulate the actions of a potentiometer moving from 0v up to 5v and back down to 0v in a continuos cycle, i also need to be able to set the increments in which the sim pot steps up in ie 0.01v or 0.02v etc, the delay between each increment also needs to be adjustable ie 0v 15ms  0.01v etc.

 

any and all help appreciated

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  • Hi Gavin,

     

    The Arduino Uno doesn't (as I understand) have a digital-to-analog converter (DAC) built-in. So there is no analog output capability. It would require an external DAC circuit or perhaps PWM suits your needs. You didn't specify the actual end goal so it's not clear. It might or might not meet your needs.

    Anyway, PWM provides an output which changes rapidly and the _average_ voltage over time can be set to (say) 0.1V or 0.2V. But at any point in time the actual voltage will be close to 0V or 5V. See here for more detail:

    PWM

    There is also information at that site on how to smooth the output so that the average looks closer to the actual output at any time, and that involves at the least using a resistor and capacitor (the formulas are there too). This is still just an approximation of what the potentiometer is really doing, and again to know if it would meet your needs would require knowing a lot more detail about your end goal.

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  • Hi Gavin,

     

    The Arduino Uno doesn't (as I understand) have a digital-to-analog converter (DAC) built-in. So there is no analog output capability. It would require an external DAC circuit or perhaps PWM suits your needs. You didn't specify the actual end goal so it's not clear. It might or might not meet your needs.

    Anyway, PWM provides an output which changes rapidly and the _average_ voltage over time can be set to (say) 0.1V or 0.2V. But at any point in time the actual voltage will be close to 0V or 5V. See here for more detail:

    PWM

    There is also information at that site on how to smooth the output so that the average looks closer to the actual output at any time, and that involves at the least using a resistor and capacitor (the formulas are there too). This is still just an approximation of what the potentiometer is really doing, and again to know if it would meet your needs would require knowing a lot more detail about your end goal.

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  • in reply to shabaz

    what im trying to do is control a scan feature that is used in a radio. currently ive got it my sketch set to recognise 0v - 5v on pin a0 from the pot for the scan range so 87.5 to 108. i trying to find a way to drive that pin a0 up and down continuously without using a pot. ive also been looking at making something to drive that pin maybe using a 555 timer or something

     

    edit

    ok my boo. the pin im using for the pot is a0 this connects to the center pin on the pot