Big Hybrid H Bridge motor driver, inspired by CtC


I found this site for almost a year ago and I must say it is incredible! Full of useful information and creative, helpful people!

When I saw Chris the Carpenter driving around with Walter I just couldn't help my self wanting to be able to drive 2 * 12V motors with speed-control from a microcontroller. Think about what you can do! :D

Chris motor driver (witch is used in Walter) can be found here:

It was originally designed by BaseOverApex and modified by robologist.


I have to thank this community for its "open source"-minded thinking. It has ben fun and interesting reading trough the old posts on this site about making a big motorcontroller. Here are some of them:




This is my version of the motordriver designed by BOA (robologist mod).


Today I soldered the last parts on the board. I have just had time to test that channel A is working, but it feels so fantastic that it is working so I just had to post this.


The building process:

The plan in eagle cad. This is the second circuit I ever made, so it's not that fancy, but it works.

Messy desk

Cutting the PCB with a scrollsaw.

Ironing the pattern.

Soaking the paper.

Toner transfer complete

Etching the board!

Removing toner with acetone.

Drilling holes.

Board bottom side.

Board topside.


Components in place!!

Had an old oversized heatsink from an old amplifier.

Board complete, it is now in the "test, analyse and evaluate"-stage.

-And also a thanks to djhesit8, you know why! ;)


We might be seeing this board in action in the near future.

Awesome! And props to you

Awesome! And props to you for giving credit to those who inspired you.

Can’t wait to see it in action.


Ok, this is just a bunch of too-much. First off, I want one --mine looks like crap now! Second, the shout-out in the corner, nice. Resurrecting old nodes and bringing new life to them --super cool. Not to mention, a nice clean etching. Well done, simply well done. I gotta tell ya, you got yourself a pretty beefy board there. I have popped a 50amp fuse so I know I have at least put that much through it and the board took it. I would be willing to bet you could shove 30 amps per channel through it if you wanted. I like that enormous heatsink you got there --This will probably save you a bunch of mosfets. I fried tons before I wised up and added my heat sinks.

I think the only thing you need to know is pretty simple and you probably already know it --With relays taking care of the reverse, you have the ability to “slam this thing into reverse” at any time --Don’t do this. :slight_smile:

Actually, you really should just be aware that this problem exists and code around it. And really, it is just when your speed is getting up-there that you need to start worrying. I personally lower my PWM to 0, then click reverse, then send the PWM back up if I am at any real speed. I also have a high-speed lock-out on my RC set-up. This way, I can give anyone the remote and I don’t have to worry about them banging-the-sticks.

That’s about it, just the “relay thing”  --You just made yourself a very nice board there, my friend. Good Job.

P.s. You reinspired me --I think I am going to redesign this board myself and see how small I can get it. I will have SparkFun make it. When I do, I will be sure to order a couple extra to send off to you.

P.p.s. Video please.

Very Very Very Cool.


You should post the CAD file …

Jeah, but I am not so proud

Jeah, but I am not so proud of the design, and it is designed for the heatsink I have, so I figure anybody could do a better job him/herself.

BUT if someone wants to make one and really wants to have my design/is incapable of producing one/has no spare time, just contact me and I will send it to ya.

best regards


:)Yeah, I’m fully aware of


Yeah, I’m fully aware of the “slamming” problem caused by the ratings on the relays (15A), and will try to code around it. I don’t think any motor driver in this class can manage to
slam motors from full forward to reverse with a load.

Now I will have to choose whether to have one big fuse or have one for each motor. And if I use normal or reset-able ones and what values.

Then there is the other problem you mentioned. If (or when) the mosfets burn, they will burn closed so that the motors will be left spinning at maximum speed.
I’m thinking of adding a kill-relay depending on how I am going to control this thing. For now I only got components for controlling it wirelessly with a Sony remote :).
Maybe I will have to have a different brain to listening for the “kill” command.

I think I will buy 2 cordless drills for 10€ a peace and go from there.

Here is a quick video, my pocketcamera was out of juice so I had to record it on the phone. Just speedcontrol from one channel, no fed/rev.!

PS. My friend will lend me a cheap MIG-welder for a year. :slight_smile:

**PLEASE Post your eagle files. **

Or atleast tell me what foot print you are using for the relay’s :slight_smile:

I created every part by my

I created every part by my self in eagle so that it was easier to change size of the pads, vias and the distance between them. I actually had a nice time figuring out the dimensions from the relays datasheet. (

but then i just used the dimensions from this

I sent you an e-mail with my custom made eagle parts library for the motor controller. Double check them before use. I don’t want to be the one responsible for a faulty motor driver, that is what you are going to build right?

jeahjeah, 21.2 twis, but

jeahjeah, 21.2 twis, but still.

Thanks man your awesome

Thanks man your awesome, I really appreciate it.

ah :smiley: first I didn’t know

ah :smiley: first I didn’t know why was you giving me the credtis :smiley: than I saw your name and remembered this: “yo DJ! spin that eagle” by the way nice :smiley: really nice… I will have to make my boards now for a PID LFR but I don’t have a printer… my friends printer is empty, and here where my father works its ok but I don’t have glossy paper by the way.


I like the silkscreen you made… I was thinking on this too but as I am using 2 sided boards, I can’t make it :smiley: :)) too hard :slight_smile:


btw awesome thingy you made here. I started bith a big bot, than a pocket sized, now I am thinking on making a huge one but no money :frowning:

renkku please send me the

renkku please send me the schematic :slight_smile: Thanks