High-amp DC Motor Control Shield for Arduino

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Anyone who has spent time with a microcomputer knows the importance of electrical power. The DC Motor Control Shield with XMC1202 for Arduino is a power controller for servos, motors, robotic actuators, and other items that need activation via a big boast of power. This shield was designed to control large motors up to 30A—yeah 30As, as in thirty amps. In case you aren’t fazed by that number, all it takes is one amp to kill you. Your car battery doesn’t put out 30 Amps.

So, let’s look carefully at this fire engine red board. It’s designed for the Arduino Uno or the Infineon XMC1100 board. Both are programmable using the Arduino library. The DC controller board has its own logic controller built into it to alleviate some of the computing power of the main board. The typical output for this board is between 6 and 40 volts. I found that I could push that output up to almost 70 volts by keeping the amps down. There wasn’t too much smoke when I ran that test.

Push to the limit

My goal was to try and hit 110 volts, but I also need to be a responsible tester. My 70 volt test was at 1.5As for 0.38 seconds. The board held up well. The discharge was beautiful to witness as the DC arched to the closest metal object I had. So there went my screwdriver flying across the lab. I wear googles for safety from flying objects.

There is a massive capacitor sitting on the top of the board. If you’ve never played with a capacitor, it’s like a battery because it stores up electrical power. Unlike a battery, the capacitor discharges the built up electrical current in one big burst, like a flash bulb. When the capacitor is built into a system like this DC controller, the board is able to take low voltage and convert it to much larger current. It’s like a transformer, but it builds up power instead of reducing it.

I like big motors

I could get into a lot of trouble with this board. It was designed to run two DC motors or one large motor. Let’s remember that a servo is a motor that operates in several directions. For you Arduino robotics folks, this is the board you need if you want to pick up or move some serious weight. If you hook it up to an actuator, which I did, you have a wonderful torque to power ratio. What this means is that you can get a nice steady feed of juice to fully and repeatedly move that actuator, motor, or servo.

With the kind of power provided by this DC Motor Control shield, you could pick up a vehicle. Think I’m kidding? A hydraulic actuator running on 12 volts at 10 amps can produce 1 ton of torque. Your car doesn’t weight that much if you are picking up one end. Carefully consider the implications of this level of power coming from a 5-volt powered device. Yeah, now think about other things you can do with this much juice coming from such a small board.

Iron Man suit, and more

If you haven’t seen Iron Man, take a closer look at his suit and see how he uses his power to juice up his exoskeleton. Granted, you would need several of these boards to operate a full suit, but it is quite possible. Halloween could be really fun this year if you run out and buy a couple of these from Element 14. The board has overtemp, overvoltage protection, and the usual assortment of heat sensors and self-protection methods for guys like me. When the board detects a fault, it just shuts off instead of other boards that will keep accepting power until they fry themselves. I’ve fried way too many boards in my lifetime. This one held up to my punishment very well.   

There are plenty of neat things you can use this board for. You could use it to slew a camera mount, operate a deathbot with a chainsaw for an arm, turn on your sprinkler system, move a conveyor belt, power a laser to put holes in walls, and other lovely projects.

Element 14 has this board as part of the kit. Programming is fairly simple, or as simple as Arduino lets it be. The idea is to think about other things you can use these boards for. We call this hacking. It is also called inventing. Grab a couple of these boards and build your own power suit. Then pick some cars up and move them around like toys.      

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Bob Monroe grew up in Southern California before he joined the U.S. Army in 1985. One of Bob's first military assignments introduced him to the world of hacking. His prankster ways ended abruptly in 1996 when he was almost caught hacking by an eighty-two year old librarian. This incident led to a renewed interest in cyber security, as a good guy.


A car's battery does, in fact, put out more than 30A. When the engine is cold, the starter can draw more than 200A -- much more in some cases. The battery itself may be able to deliver 1000A into a dead short.

And "1 ton of torque"? Torque isn't measured in tons. It has dimensions of force times distance.

Theoretically, a dead short across the battery terminals results in infinite amps. Also it only takes 100 milliamps, 1 tenth of an amp, in the right place (across the heart) to kill a person.
The power source responsible for the most electrocutions in the USA is your standard household voltage of 110 VAC. For your safety, keep that in mind.
Electrician for 30+ years

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