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Thread: A question about micromouse comp. at techfest

  1. #11

    Default micro mouse

    hi friends i am also working on micro mouse i have made my dc geared motors with 1:50 reduction ratio. i have "jugar"for optical encodes(relative encoders) to read the motors movement. i will be using pic16f84aor 16f628a . any open advices or guidance. let me know.
    asimov_18

  2. #12
    Senior Member Cyborg
    Join Date
    Sep 2004
    Posts
    162

    Default

    Hi Asimov_18

    What kind of circuit are you using to drive your motors ?

    First complete what you are making and planning, and then consider the following suggestion.

    if you somehow measure the current flowing through the 2 motors by your MCU, then you can control their speeds such that they remain equal. Hence the tendency of the robot to run into one of the walls would be very less.
    This is helpful if you are using a digital type sensor to sense walls.

    To sense current of your motors -
    If you can afford about 0.5 volt less to your motors, put a very small resistor in series with your motor.

    now make an op-amp amplifer with a gain of 10, to amplify the voltage across this resistor, and feed the output to the ADC in the MCU.
    the 0-5 volt signal is linear with the current in the motor.
    (use the differential op-amp configuration for better results.)
    (the series resistor would be 1ohm or less and calculate its wattage and put a high wattage resistor else ...smoke..)
    (if you use LM324 kind of op-amp note that its max output voltage would be about 1.5V less than VCC.)

    well this is just an extra control loop for both the motors which would make the robot very smooth and straight runner.

    cheers!
    Vivek
    --
    " To get working ideas effectively, I try to fail as fast as I can. "
    Richard Feynman
    --
    http://www.youtube.com/watch?v=JqlawTD_9B0

  3. #13
    gopoo
    Guest

    Default better not to go

    dont go for dc motor,they are hardest to control....and stepper motor are
    very easy to control.....if you want speed from above discussion you can understand stepper can give speed up to 2 m/s.... believe me,i made three micromouse ,two from dc motor,one from stepper motor,only one is working which is of stepper motor....

  4. #14

    Default micro mouse

    hi goopo u said u had made three micro mouses . tell me more about them you know other peoples experiences r great for learning. thanks
    also send me ur email addess.
    asimov
    asimov_18@hotmail.com

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