Hacking a tank toy

Wardy hacked a tank toy he got from eBay. Motors are driven through a L298N dual full-bridge driver, while the tank is currently controlled with an Arduino. Soon the Arduino will give way to a Propeller-based custom board.

That toy tank I snagged on Ebay has undergone some surgery to remove the hideously cheap and nasty motor drive circuitry – only to be replaced by some half-baked contrivance of my own doing.

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  1. You are replacing one horrible motor driver (you didn’t give out the details), by anoher one, not less horrible!

    The L298N “wastes” a MINIMUM of 1.8V on the drivers alone, with a maximum value of 3.2V (@1A load) or even 4.9V (@2A load).
    From the look of your circuit you are running it with 8 x 1.2V cells, or 9.6V. This means a significant part of your power is wasted on the L298N itself, not on your motors.

    I have recently bought an L298N myself, but when I bothered really looking into the datasheet and realized how awful it is, I dumped it in favor of a tiny Pololu DRV8833-based board. The DRV8833 from TI is a MOSFET-based H bridge, and the total bridge resistance is 0.36 ohm. At 1A, this translates to 0.36V vs the L298N’s 3.2V.
    When you compare it to the L298N, the total size of the pololu module is about the size of the L298N itself, and unlike the L298N that requires a large heatsink, the DRV8833 chip is a tiny 16 pin PQFPN device, less than 5mm on each side. Ofcourse, a heatsink is not needed.

  2. Thanks for that info on the DRV8833.

    No clue given as to why he’s switching to a Propeller from Arduino.

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