Wednesday, June 10, 2009

The Prototype "LV Tanker"


The first prototype with working Arduino, Adafruit motor shield, XBee, XBee adapter, motor power pack and 9V Arduino power, plus the Arduino sketch and Windows controlling program. The first try was buggy but working. Update: It turns out that the rechargeable power pack (from a swiffer) used to run the 2 DC motors was overheating the H-bridge on the motor shield. After switching to 4 AA batteries everything ran smoothly and we were able to drive it around the house.

10 comments:

  1. What kind of motors are you using?
    If they are servos, I would remove the motor shield and replace it with the proto shield controling the motors with the analogWrite(); function on a PWM pin.
    Nice job!

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  2. Looking at the image, I'd say it's using DC motors, which makes the motor shield pretty essential.

    Looking forward to seeing how this project progresses!

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  3. In the prototype we are using little motors from a Tamiya kit, but since this is a battle-bot and needs a lot of torque, we have purchased 2 Black & Decker cordless screwdrivers. We dismantled the prototype today and started back on the real thing.

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  4. Mark:

    As it turns out the motor shield is not working for our DC motors - the h-bridge is overheaing and cutting out. We will likely follow your suggestion and use a L293NE as shown here http://itp.nyu.edu/physcomp/Labs/DCMotorControl. Do you think that is a good idea?

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  5. Great job man! I can't wait to see the latest developments with this project!

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  6. So it turns out that the L293NE motor controller is about the same as the Adafruit shield. Both overheat wildly when the motors are stopped. The Adafruit shield L293D finely overheated and died while testing. We just received transistors with heat sinks from Mouser. Will let you know how it goes.

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  7. I've burned out a few adafruit motor shields. The 1.2 amp limit is very low, even if you bridge two of the outputs to get 2.4. I like standard H-bridges with high power transistors, as you can get much better specs and overall control.

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  8. FYI - Our new H-bridge design with high-power transistors like Mark suggests is now at http://sports4nerds.blogspot.com/.

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  9. So after a little delay we are back in business. Our h-bridge design was still overheating. The spec was designed to be 2 amps, but our voltage is low and our amperage is high and it did not work out under heavy load. We got a pair of relays from Mouser and now we are cooking. We will add the new h-bridge relay design as soon as it's fully tested.

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  10. To all - the real LV Tanker is done (the first version anyhow). You can check it out at http://sports4nerds.blogspot.com/. Thanks for all the nice comments.

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