Let's Make Robots!

Motor Shield Recommendation

The motor shield I have interferes with using interrupts, PWM and servo library. So now I'm looking for a new one, any suggestions? I have a proximity sensor set up as a bump switch and would really like to move the code out of the loop and trigger the code with an interrupt. The motor shield I have uses pins 8, 9, 10, 11, 12, 13. Pins 10 & 11 are the problem.

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Buy a Sabertooth from Dimension Engineering??

Their expensive, but worth it.

You can control them with one pin via simplified serial or packetized serial.

build your own motor driver shield. Either, buy a breadboard shield or a protoboard shield and add a couple stacks of 293s or 754410s and route the pins you want to use to the motor drivers, maybe using a hex inverter or a couple discrete NOT gates.

Stacked drivers to get more current per motor
http://www.starlino.com/motor_driver.html

How to include the NOT gates to save pins
http://letsmakerobots.com/node/32462

BYOB is great for complete control over what you want but I'm trying to get with the times and take advantage of current offerings. Otherwise I'm back to my CanBot (I could hijaak the h-bridge I built for that) and re-inventing the wheel (or motorized wheel) so to speak. I'm just trying to avoid the trial and error of buying boards until I find one I like. Don't have the funds for that.

Also, I have other ideas in mind that keep me from going the homebrew route. The ability to use off the shelf products would be handy as this is just a test platform and the final product might not be one of a kind. :-)

For the Rad Base that TWERP and ServO use, the L298D is probably a better choice than a 293 or a 754410 w/o diodes.  I use the "official" Arduino.cc R3 motor shield (mfd. by Smart Projects, or the "RadioShack Version.")  If you cut the braking traces you're down to pins 3/11 for PWM and 12/13 for direction control.  That doesn't solve your pin 11 problem, but it cuts down some of it.  Another option is a go-between shield.  If you're happy with the performance of your current shield it might work.

I wouldn't recommend the Adafruit shield for this.  I burnt out 3 ICs on one of these (one 293, the 754410 I replaced it with and the 595-which makes no sense.)  TWERP does carry a lot less weight than Serv-O though, so the current drawn may not be as high and may not cause the same troubles for you.  On the Adafruit shield, Digital pin 11 is only used if DC Motor #1 / Stepper #1 is active and Digital pin 10 is only used for Servo #2 control, so with four options for DC motor control you're in the clear there.  Also AFMotor.h is a brilliantly elegant library.  It lets you use object-oriented commands (more like C+ than C or C++ the way I understand them) to control motors.

 

 

 

I had a look at that and it looks good. Unfortunately I'm not seeing a lot of tech info on some of these board (cheap on Ebay). I see one stamped ladyada.net/make/mshield, is that the Adafruit shield you mentioned? I don't see info on pins used.

I would stay away from the motor shield on http://ladyada.net/make/mshield/  It is okay and has 4 motor control or 2 stepper motors but little access to the other pins.  To connect to other pins you would need to solder on wires   Not a great idea for quick prototyping. 

 

I know I am replying to an old post but I have the card in hand and am not happy with the design. 

 

 

 

Shon

I can see what you mean. It's not a typical breakout board. It's great if one knows what their getting and knows how to use it but the the "in" pins on the motor controllers are connected to pins on a shift register. This allows four motors to be controlled (with dynamic breaking) using seven I/O pins on a microcontroller. If one wanted dynamic breaking, controlling four motors would normally require 12 I/O pins.

This is great if one knows how to control a shift register (which is pretty easy compared to a lot of ICs). But if one were expecting a L293D breakout board, I can see how one could be disappoionted.

 

That's the one.  Adafruit.com is the commercial component of ladyada.net.  Limor Fried is an MIT Engineer (I think it was MIT) who was a big part of the beginning of the maker movement.  All (or most) of her hardware designs are open "source" so a lot of chinese manufacturers download the Eagle files and mass market them cheaper than you can get them from her.  (At least you get a tested board that way and don't have to worry about screwing up the assembly yourself.  Not that that has ever happened to me!;-)

Look at the FAQ to that shield (http://ladyada.net/make/mshield/faq.html) about a pagedown and a half to get to the pin out information.