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I am starting a project with my arduino but need some help

jaytech101

how do I get negative input and how do I detect difference between the data as it changes constantly.

  • 0

    Hi jaytech - I'm going to move your question over to our Arduino group to see if anyone over there might have some ideas for how to help. 

  • 0

    Hi Jay,

     

    jay burke wrote:

     

    how do I get negative input and how do I detect difference between the data as it changes constantly.

     

    Are you trying to measure an analog voltage (using an ADC) and have a negative input?

    If so, a bridge rectifier can be used (and then there will be the diode volt drop to take into consideration, although this can be reduced with Schottky diodes). There are other ways to eliminate the drop, aka 'precision rectifier' which is a more complicated circuit.

     

    If the data is changing, then this can be normal with an ADC - you could take an average (if this is a valid assumption for the type of signal expected on the input).

  • 0

    Hi Jay

     

    Not sure what is the application.When asking a question give all the data you think would be helpful for nus to understsnd what you are trying to accomplish. More is surely better in this case.image

    The most accurate and simple way is to use an op-amp.This will translate the negative voltage to a positive voltage of the same value. Hope this helps.

    Bill

    .image

  • 0

    Hello, Not K.

     

    If you are trying to detect a negative voltage relative to ground potential of the 'Duino; put a reversed InfraRed LED from the input signal to ground with a current limitting resistor and then set up a IR detector on one of the 'Duino's digital (2nd) inputs.   You will also need a blocking diode on the first input pin to keep it from 'seeing' the negative voltage.

     

    Happy Trails

     

    -=SyntaxMatters=-

     

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