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I'm working on building my first robot. this is my first foray into DIY electronics. I already have an Arduino Uno, and I have ordered the Tamiya double gearbox here. My goal is to control the gearbox to move the robot, but from what I've already read, I need to have something between the Ardiuno and the motors. It seems like people have trouble doing that because the included motors are low voltage, so the Arduino motor shield won't easily work.

I'm looking for a clear solution to making this thing run, in the simplest way possible. One thing I'm considering is replacing the motors in the gearbox with these motors. If I do that, am I right in thinking I could run them from the Arduino motor shield?

If there is a simpler (or cheaper!) way of making it work than being stuck on the Arduino Motor shield, I'm game for that. I've just gravitated to that solution because it seems simpler as an electronics noob. (I haven't bought that shield yet.) But I'm really open to other solutions, so if you can, I'd appreciate the advice!

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Here's what I've found about both the motor shield and the motors:

  • Motors are 3-6V and will use a lot of amperage. This may be a problem with a mobile robot. You'll have to figure out a power source that can provide 4+ amps... on battery power that's a lot. Personally, I would go with a continuous rotation servo for a compact, light robot.
  • Motor sheild can provide 2x 2A channels at 5-12 V (Source) using the two + and - terminals on the bottom left side of the shield. You must connect external power, because USB can't provide enough power. I can't find if the motor shield will limit current if it goes over, but if you do use the gearbox, I'd recommend another route for control that's 1/6rd the price.

This chip was recommended by Pololu on the product page.

Time to whip out your soldering iron! Really, soldering is a great investment and you'll get to a point soon where you'll need one; there will be no other alternative. Luck for you, you only have to solder 16 joints. Headers are included.

Diagrams from Pololu's site:

*(Click to enlarge ^^^)**

*I added a little text to this image.

  • Thanks! For clarification, if I use the controller you mention above, then I can just use the included motors, correct? – Steven Hovater Apr 27 '14 at 20:58
  • Glad I could help! Yes, @Steven, you can use the included motors. Also, the controller is linked from the motor product page FYI. – Anonymous Penguin Apr 27 '14 at 21:02
  • Great. One last question—if I'm following the controller's datasheet correctly, in code on the arduino I simply set the pin connected to Ain1 to HIGH to go forward. Do you think that's correct? One of my reasons for trying to stay within official Arduino stuff earlier was that I'm a bit intimidated by going off-reservation code-wise! You've emboldened me, though! – Steven Hovater Apr 27 '14 at 21:25
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    @Steve Glad I could help. Umm for the datasheet, it says on page eight, table two, that one pin does forward, the other one backward, and both is to brake. If no power is applied to either pin, it'll be free to rotate randomly. – Anonymous Penguin Apr 27 '14 at 21:48
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The FA130 type electric motors in the Tamiya Double Gearbox Kit (No. 70168) are 1.5v-3v DC motors with current ratings of 0.20A (no load), 0.66A (@ max. efficiency) and 2.2A (stall), see 1.5-3V DC Motor 6990 RPM. They are not high current motors.

  • Hi Andre, and welcome to Arduino:SE. 'High current' is very much a relative term. That stall current of 2.2A may be too much for a 2A line on a motor shield. – sempaiscuba Aug 22 '18 at 14:20

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