Make an 8-amp Dual Motor Controller For $40

Picture of Make an 8-amp Dual Motor Controller For $40
The OctoDriver is an open-source 8-amp Motor controller. Connect it to your Arduino, Propeller, or PICAxe to control more powerful motors!

I've been working on a dogie door for a while - while the software is straightforward, finding a suitable motor controller has been more difficult.

The problem is that a lot of the inexpensive motor control shields are just too meager to control anything but the most dinky motors.  ladyada's Arduino shield only does 600mA continuous, 1.1A peak . Pololu makes beefier motor controllers, the DMC 01 can do 13 amps, but it's pretty expensive (about $100). 

So I've been on the lookout for a high power, inexpensive, and easy to control circuit - I was flipping through starlino's website and I spotted exactly what I was looking for. His idea is pretty simple: why not combine 2 motor controller IC's to split the load?

He calls the circuit the 'OctoDriver', it combines 2 h-bridges to provide 8 amps peak, 4 amps continuous. I asked him if I could put it on a PCB, and he thought it was a great idea. I couldn't think of a better name, so I call my version "The OctoDriver".

I also put it on a Propeller Platform compatible footprint, so it can be used on a breadboard, perfboard or with a Propeller microcontroller. The design is available under the MIT license, so anyone is free to hack away.

The OctoDriver is also available as a kit from Gadget Gangster.

Flip to the next step and I'll give you some more technical details on the OctoDriver and show you how to use it.

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teknas0715 days ago
could it be made as a 12a dual motor driver if yeas wat changes should be made
schel2 months ago

SUH-WEET!!! I'm on it!!! Much Thanks!

wonderin' if this would drive a single 24 VDC scooter motor ? the batteries that run it are 2-12 vdc 10 AH....wuddya think? though I know I dont need the "Octo- " dual aspect of this instructable, I too cant find anything beefy enuff to safely drive that motor. Thanks for ANY input!!

infoseek083 months ago
Great Project!!! I would love to build this project with the PCB you had listed on your website. I signed up to be notified if and when the board will be available. Do you know if we can still purchase it or is it a discontinued item?
I am planning to buy a new DC motor driver board which can run 5amp motor but I don't know how to connect it with Atmega 8A chip. Please see the pdf I attached for Atmega 8A.

Here are the 7 pins in DC motor controller:-

Pin No. Pin Functionality
1 GND Ground
2 IN-1 Logic input for the motor direction.
3 Diagnostic 1
(DG-1) Output pin with logic 1 output in normal operation. Represents side of the internal
H bridge corresponding to IN-1. Pin is pulled to logic low by the motor driver in
case of over temperature or overload due to short circuit.
4 PWM Used to apply Pulse Width Modulation to control motor velocity
5 Diagnostic 2
(DG-2) Output pin with logic 1 output in normal operation. Represents side of the internal
H bridge corresponding to IN-2. Pin is pulled to logic low by the motor driver in
case of over temperature or overload due to short circuit.
6 IN-2 Logic input for the motor direction.
7 CS* Current Sense output to measure the current flowing through the driver
vectorges4 years ago
Questions from a newbie. Would it be possible to increase the amperage  by using something beefier than the TI SN754410? My project is to control a pair of motors (from a scooter chair) to power a small boat.
Gadget Gangster (author)  vectorges4 years ago
At that point, you probably better off using a mosfet powered controller - BJT based H-bridges are going to waste too much heat for your application.  Check Pololu for some nice ones.
guerd874 years ago
Great Project. I have been stuck in the same boat really looking for a motor driver. My next real option for power was to build a H-Bridge circuit from Mosfets, which would give me tons of power but at a high price :(

Im going to run down to Jaycar tomorrow and pick up the parts and get it breadboarded up for my Arduino

Good stuff :)
frollard4 years ago
Fantastic project! any thoughts on open-sourcing the complete schematic/board layout files?  Looks complex to diy the circuit board, not not impossible :D

Silly question:  Those traces look a bit small to handle 8amps at 5 volts...I'm guessing that gets proportionally less to suit the max motor voltage (to match the total wattage...)
Gadget Gangster (author)  frollard4 years ago
Thanks! It was a lot of fun putting it together and testing it. I threw some fairly massive softball-sized motors and it worked like a champ.

I'm working on a battery pack for the Propeller Platform, too - so the next step will be to put the OctoDriver in a wheel robot with some UPS batteries, running the Prop logic on a separate battery.

The schematic / layout files are under the MIT license (essentially public domain) - there's a link to download it in PDF or diptrace format on the last step.  Same deal with the Propeller object.

The board uses thicker (taller) traces than usual to support extra current (4 oz instead of 1 or 2) - it will do just fine providing 4 amps continuous to each motor 8 amp peaks are fine, too.
Thanks for the quick reply!  Really neat stuff; I never realised the dip link was another format :) silly me!
Gadget Gangster (author)  frollard4 years ago
No problem!  Diptrace is my favorite program - there's a freeware version that works just fine, too.
milsorgen4 years ago
 Top goal!

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