Wait so if they can only
Wait so if they can only drive one motor at a time, how do I connect it to the PWM Outputs of my MCU using only one port? Do I need an onboard MCU to take care of the serial commands to translate them into highs and lows? Or can I do this in the software of my MCU, making a PWM output? Is it that easy? Because this is a much cheaper method than those highly sought after sabertooth regenerative drive motor controllers.
I think you are getting
I think you are getting confused a bit. Both motors can be driven at the same time. What I was saying is the controller featured here is designed to drive a single motor. You’ll need to build two of these circuits (one for each motor).
You can translate the high, low and PWM commands from your MCU. Or, after I finish the new controller with integrated MCU, you’ll just send a set serial string to the controller to tell it to got FWD, REV and Set Motor Speed. The method I present here is a heck of a lot cheaper and is very robust. I’ve been running different size motors on it all day and have yet to have any problems. If you elect to build this circuit on a proto board you’ll cut the cost down to about $17.00 a controller and maybe cheaper if you do some good searching for components. I found a ton of what I used in this circuit on ebay for a lot cheaper price.
What MCU are you planning on using? Maybe I can help you out.
I was planning on using an
I was planning on using an Atmega8 Because I have many spares.
That should work. What
That should work. What programming language are you using? Are you using AVR Studio, Codevision, etc…
AVR Studio -C++
AVR Studio -C++
But the problem is I am a terrible programmer 
I found this schematic for a
I found this schematic for a Motor Driver capable of handling the amount of AMPS simialer to yours, depending on the relays. It only has one PWM chip, and can drive two motors and operating voltage is extremely high (30ish?)
http://rapidshare.com/files/189723632/MC7_Schematic.pdf.html
Is it good for my task? (Sending high/low commands from MCU PWM output?)
My final design will have 1
My final design will have 1 PWM chip and have functionality to drive both motors on the same board. This version was for more of a proof-of-concept. However, it has turned out to work very well so, instead of chucking them aside like so many of my other concepts, I’m going to actually use these. I’m almost done with the redesign. I still need to post the board files for the current design. That’ll have to wait till I’m done with my 4 hour layover at Denver Airport.
The design you posted will work for you and has some similarities to mine. It looks as though there is a dedicated PWM chip whereas the PWM signals from my design comes from a dedicated microchip. This way, I can modify the functionality as I see fit.
"My final design will have 1
"My final design will have 1 PWM chip and have functionality to drive both motors on the same board. This version was for more of a proof-of-concept."
Looking forward to that, and thanks for your insight and wisdom, every appreciated, I think I will try your board, as well as this schematic I found because yours has an MCU and I am a bad programmer, and just grab snippets from other people’s source code.
This conversation is going really far to the right 
So the final bill of
So the final bill of materials, does that correspond the the bottom most schematic?
The B.O.M corresponds to the
The B.O.M corresponds to the second to the bottom schematic (the one without the NOT gate). I’m using that version as the microcontroller in the new design has plenty of I/O pins. I finally got my YouTube video camera but i will have to wait till I get back home off of my business trip to shoot some video.
**0o0o0oh busy busy man **
0o0o0oh busy busy man
I said screw it… a friend
I said screw it… a friend bought me a sabertooth 2x25 25A motor driver from DE… time>money
Good choice for a
Good choice for a controller. I just got home this weekend and I made a video yesterday after watching the super bowl, rewrote the test application, finished making a bench power supply so I can get rid of the batteries for now and worked more on the microcontroller code.
Good choice on the Sabertooth as it is very reliable. I’ve used those before and with this project I decided I wanted to have more control over the design so, everything gets designed/built by me. Also, I’ll be able to use the designs for other projects. I’ll still post everything as others may want to use them for ideas.
Good luck with your project,
Curtis
No Such Thing
As a bad programmer, you should understand the “snippet” funtions soon. I promise if you try, and follow all the directions to something like pallax’s BoE bot. you Will learn to code. The amp/hr (Ah) rating of your battery determines the amount of time your pack will output at hours rate. locked rotor current can be as high as 10xAmpre rating! 30 motor …300A inrush. I always rate relays 125% of the load. the voltage is not so important when it comes to relays and fuses. Till seeking a 36v(nom) 1hp(30A) motor controller for my scooter. BTW regenertive braking is lousy…at best in anything. soooo…much loss… heat loss, friction loss, copper loss. I’m sure that regen returns 10% of you power.
I can’t wait!!
Very nice set-up my friend… I can’t wait to see what comes of these motors and wheels. I just watched the ramp-up ramp-down video and again, a nice set-up. --I think I heard a dryer in the background, anywhere you can have that nice a shop IN YOUR HOUSE, is awesome!!
a bot?
So have you used this board in a robot yet? I like it!
I redesigned the board to
I redesigned the board to include a dedicated controller. I’m also slowly working on the platform that it will be included on. It has been slow coming as I have a lot of other projects that I’m trying to finish that will be used for the bot also. It’s kind of like one project affects the other. Currently, I’m finishing up my CNC machine that I want to use to cut out parts for the bot. That has been taking the bulk of my time. I’ve also been working on documentation for the other projects. I really need to update my progress.