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Relay circuit help

Discussion in 'General Electronics Discussion' started by Omega Ra, Oct 15, 2012.

  1. Omega Ra

    Omega Ra

    3
    0
    Oct 15, 2012
    Hey guys. a little background first. I am making a robot lawnmower based on a simple relay circuit. This is my first time making a circuit and it works, but not as I expected it to. The way I thought it was going to work was, robot goes forward, hits bumper which activates a switch to switch the relay, thus reversing polarity on motors causing it to reverse (does this) but I put bigger Caps on one relay thinking it would hold that relay open longer and thus the wheels would turn backward slightly longer than the other side, thus turning the robot when it backs up. However it only backs up, then sits there for a second then goes forward again. Here is a drawing of my schematic (sorry I am not good at it). With one alteration, I forgot to draw in the Resistors (0.25W 10 Ohm) before the first diode. toward the side I drew what the relay connections are a little bigger so it is easier to see. On one side/relay I have 2 220uf capacitors, and on the other I have 1- 220uf; 1 - 470uf and 1- 1000uf capacitors.

    As I said it drives forward fine, when it hits it's bumper it does back up, but instead of turning, it backs up slightly, sits there for a second and then just goes straight again...any help would be greatly appreciated.
     

    Attached Files:

  2. GreenGiant

    GreenGiant

    830
    5
    Feb 9, 2012
    2 suggestions, rather than capacitors, try looking into time on/off relays, most of them you can program to different intervals, much easier than fiddling with caps.

    My other thought is bring down the voltage to one wheel when it reverses, this way it will turn gradually (at low voltage differences) and probably work better since its only 1 wheel turning on its own otherwise.
     
  3. Omega Ra

    Omega Ra

    3
    0
    Oct 15, 2012
    this is running purely on relays, how would I bring down the voltage? This is my first circuit and am not very knowledgable yet.
     
  4. Omega Ra

    Omega Ra

    3
    0
    Oct 15, 2012
    Okay new Schematic

    here is a new version of the schematic. I took the original one I found online from Hubert and altered it to show how I did it. I also included his original.
     

    Attached Files:

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