SparkFun Forums 

Where electronics enthusiasts find answers.

Questions &/or issues related to products in the Robotics category should be posted in this forum. Includes Direct Current(DC) Motors & Drivers, General hardware & Chassis, Servomechanisms(Servos) & drivers, Stepper Motors & Drivers, etc.

I have a question about supplying power to the Big Easy Driver ( and RedBoard ( I am using them to control this stepper motor (

The BED Hookup Guide ( ... okup-guide) says to use a power supply that is "....capable of providing up to 2A and falls in the range of 8V to 35V." However, the Brian Schmalz BED guide ( says the supply should be a "....6V to 30V, 3A (or more) power supply that is clean (low ripple)."

Should the supply provide 2 or 3 (or more) amps to the BED?

I would like to permanently mount the RedBoard and BED in my project, and use a single supply to power them both. What would be a suitable supply? I'm not sure how much current the RedBoard will draw above whatever the BED needs for the stepper motor.

If someone could suggest a circuit I would perhaps like to build my own supply. Thank you for your help!
Hi G.

The amount of current you need depends on what motor you're using, how much torque you want to get from that motor, and how much voltage you power supply is capable of delivering.

In the case of ROB-13656, If you look at the datasheet, that motor needs up to 2 amps of current per phase when driven at it's maximum. So that would be 4 amps total for the motor since there are two phases on the motor if you wanted to drive the motor at maximum.

There's a few things working in your favor though. The first being that you generally don't need to run a motor at it's maximum to get it to do the work you need from it. The second is that the higher the voltage you drive the Big EasyDriver with, the less current you need from your power supply.

What I'd recommend is to use a 12 to 24 volt supply that's capable of 2 amps or more and you should be fine with the motor you have. Make sure to turn down the CUR_AJD control on the Big Easy to it's minimum before applying power and only turn it up enough to get the motor running smooth. If you go too high, you risk burning out the board.