Adafruit Motor Shield

Hello everyone,

I plan to control a robot chassis (http://www.robotgear.com.au/Cache/Files/ProductImageOriginals/422_RP5%20Robot%20Chassis%20-%20Gray.jpg) with my Arduino Mega 2560. Therefore I wanted to use a Adafruit Motor Shield (Arduino Playground - AdafruitMotorShield).
Hence my question: Is this Shield even compatible with the latest Arduino Mega version? And is it possible to directly control 2 brushed dc motors and 1 stepper motor at the same time using this shield only?
Help would be appreciated :slight_smile:

regards
BruteForce

Is this Shield even compatible with the latest Arduino Mega version?

It should be, yes.

And is it possible to directly control 2 brushed dc motors and 1 stepper motor at the same time using this shield only?

It should be. You should be able to connect one brushed DC motor to M1_A and M1_B, a second brushed DC motor to M2_A and M2_B, and a stepper to M3_A, M3_B, M4_A, and M4_B.

Thanks for you help!

Basically a DC motor needs one H-bridge to control it, a bipolar stepper needs two H-bridges (one for each winding).

If you only want to drive a DC motor in one direction then a single transistor/MOSFET and diode is enough.

It may not be the best solution for your stepper motor though, what is the spec of the stepper?

Bear in mind that the motor shield you linked to uses bipolar motor driver chips (L293D), so it will have quite a high voltage drop (2.6V typical, 3.6V maximum @ 600mA). Depending on the specification of your motors and stepper, you might be better off using this https://www.sparkfun.com/products/9457 to control the motors and an A4988-based stepper driver (available from eBay) to drive the stepper. These devices are mosfet based, so they have much lower voltage drops.

Thanks for your replies. Then I would consider controlling the 2 dc motors with this https://www.sparkfun.com/products/9457 and going without the stepper - it isn't that important anyway. Now I'd have one question concerning this motor driver... Do I only have to connect one 6v power supply to Vcc and GND to control two 6v motors? And is there no voltage drop?

BruteForce:
Thanks for your replies. Then I would consider controlling the 2 dc motors with this https://www.sparkfun.com/products/9457 and going without the stepper - it isn't that important anyway. Now I'd have one question concerning this motor driver... Do I only have to connect one 6v power supply to Vcc and GND to control two 6v motors? And is there no voltage drop?

Yes the board has a single motor supply input (Vm) for both motors, with allowable normal voltage range of 4.5V to 13.5V. There will be a small voltage drop, but much less than for the Adafruit shield - the datasheet quotes 0.5v typical (0.7V max) @ 1A motor current, and 0.15V typical (0.21V max) @ 300mA.

Do you know the current consumption of your motors?

The datasheet (http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Robotics/DG01D.pdf) says “No Load Current: 190mA (250mA MAX)”.

It would be useful to know the stall current as well. You can calculate this by measuring the resistance of the motor.

Unfortunately I haven't got the motor yet. I'll check it as soon as it arrives. Anyway thanks for your help, I'm glad that I didn't buy the Adafruit Shield!