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Description: The Big Easy Driver, designed by Brian Schmalz, is a stepper motor driver board for bi-polar stepper motors up to a max 2A/phase. It is based on the Allegro A4988 stepper driver chip. It’s the next version of the popular Easy Driver board.

Each Big Easy Driver can drive up to a max of 2A per phase of a bi-polar stepper motor. It is a chopper microstepping driver which defaults to 16 step microstepping mode. It can take a maximum motor drive voltage of around 30V, and includes on-board 5V/3.3V regulation, so only one supply is necessary. Although this board should be able to run most systems without active cooling while operating at 1.4-1.7A/phase, a heatsink is required for loads approaching 2A/phase. You can find the recommended heatsink in the related items below.

Note: This product is a collaboration with Brian Schmalz. A portion of each sales goes back to him for product support and continued development.


  • Bi-polar Microstepping Driver
  • 2A/Phase Max
  • 1.4-1.7A/Phase w/o Heatsink
  • Max Motor Drive Voltage: 30V
  • On-board 5V/3.3V Regulation


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Customer Comments

  • Just a “Ha … how about that!” …was watching “The Blacklist” Season #1 Episode #6 a guy is rigging a car to blow up with remote detonator [about 34 sec in] and includes a “RED” PC board in his “rigging”. Of course when I see the Sparkfun signature red board I can’t help myself …. I gotta single frame it to see if I can figure out which board it is. Sadly it’s this one. I say “sadly” because it should have been an XBee, or maybe a GSM. How you would use a stepper motor driver to blow up a car I have no idea!! (Homeland Security … please carefully re-read that last sentence .. thank you).

  • So I burned this chip out pretty much immediately, I followed the hookup guide and loaded the sample sketch hooked up my ROB-10847 stepper motor and gave it 12volts and the Allegro A4988 burned right up. Any ideas what I did wrong? I checked the resistance in the motor and was getting a couple ohms which seems about right. Is there something I could have hooked up wrong? or is their something wrong with the motor? I don’t want to buy another board and burn it up so any info is appreciated.

    • Is there any chance that there was a short between any of the four motor outputs? Or, at any time that the BED was powered, were any of the four motor output lines connected or disconnected from the motor?

      • All motor output lines where connected. I do now I measure a short on the A output of the BED but that could be because of the burnout, I don’t see any reason for a short except for the burnout.

  • I also am having trouble getting the motor to run as fast as I want . I’m using the sparkfun NEMA17 motors but have tried others too. My motors are rotating about 1-2 rev / sec. I’m using the accelstepper library (see below) code but have also used other code (stepper library).

    I’m following the diagram for jumping the microstep pins to ground to set the resolution to FULL STEP (MS1, MS2, and MS3 jumped to Ground) assuming FULL STEP means quickest speed (right?)

    However the motors run really slow (like 10 RPM) , but when MS1 is jumped to ground and MS3 and MS2 are floating it seems to run about 1-2 rev/sec but that’s still too slow. I assume I can run these motors much faster and I’m not understanding something about the motor driver.

    FYI using arduino w/ library accelstepper : this is what I have in the loop stepper.setMaxSpeed(20000); stepper.setSpeed(20000); stepper.runSpeed();

    • One thing to keep in mind is that stepper motors (at least with low end drivers) are really made for very fine position accuracy, not speed. Torque drops off with speed, so at some high speed you will get zero torque (which means your motor will stop spinning if you accelerate up to that speed). Normally with a BED at 12V and the simple NEMA17s, I can get up to about 15,000 to 20,000 microsteps/second before the motor has zero torque, which is about 10 revs/sec. Note that you HAVE to accelerate smoothly up to these speeds, you can’t just start from zero and jump right to 20Ks/s. Adjusting your current set pot on the BED can make a huge difference to your max speed and torque, as can adjusting your input voltage. Also note that on a normal Arduino, Accelstepper can’t go much higher than 4Ks/s. With a faster board like a chipKIT Fubarino Mini or Fubarino SD, Accelstepper can easily hit 20Ks/s or more.

    • sorry i realize this is probably for the forum not here. i cant figure out how to delete it.

  • This stepper motor driver is getting very hot. i am following the wiring exactly in the bildr article and using 30 V. However I tried with 20V, 18V, it is all making the chip pretty hot. is this normal? the amperage draw is between 0.3 and 0.7 for my motor. That is well within the big easy drivers rating. any suggestions?

    • The driver chip will get very hot, depending on your input voltage and current setting. At 30V input, you’ll be generating more heat with the driver chip than at 12V for example. I’d try adjusting the current set pot on the BED. Turn it down some, and you will notice the driver chip doesn’t get as hot. You will need to tune the current set pot for the smoothest (but still strong) stepping of your whole setup.

    • Are you using the Enable pin on your board at all? If you don’t use that, I’ve noticed a huge temperature increase, whereas with the use of the Enable pin, it helps keep the motor and the BED much cooler.

  • Hello, I want to control 4 stepper motors of 24v and 2A and 4 of these drivers are looking the most promising option right now. My concern is what kind of power supply do I need ? Would a 24v 60W power supply with 2.5A be able to power the four drivers and motors ? Do the power supply need to have an exact amperage of 2A ?

    • The power supply current you’ll need is not obvious, because of the way chopper drives work. For example, when I run a BED at 12V and am putting 1A through each coil of a motor, I only draw about 800mA from the power supply. This is because the current chopping action of the driver is sort of acting like a switching power supply, trading off a lower voltage to the motor for a higher current. Sort of.

      So if you are running four motors through four BEDs at their maximum currents, I’d suggest you get a power supply with at least 6 or 8Amps to be safe.

    • You might want to check out their quad stepper driver part # ROB 10507 paired with some heat sinks. Might be better than using 4 separate drivers. Just a thought

  • What is the difference between the ROB-11876 and the ROB-12859? I just bought 3 of the ROB-11876 about a week ago. The specs say that the 12859 can handle up to 2A and the 11876 only could handle up to 1.4A. Is the 12859 capable of handling more Amps? If so , How can I exchange the ones I just bought for the better ones?

    • You are correct, the major difference between ROB-11876 and ROB-12859 is that this new version is capable of handling up to 2A (as opposed to 1.4A). There were also a few other things updated as well, but the Amp change was by far the major update. That being said, I am fairly certain our Support team can aid you with this issue. Just email and they will be able help you out!

      SparkFun Return Policy

    • Both of those boards use the same driver chip, the A4988. Both drivers can (theoretically) deliver 2A (or a bit more) to a stepper motor coil, with lots of heatsinking and forced air cooling. Both can deliver about 1.4A in ambient air with no heatsink or fan (this value depends a lot on what motor you’re running and what power supply voltage you are using - thus the 1.7A figure above. I normally say 1.4A to be safe and conservative.). There is no difference between the two with regards to this spec. The 11876s that you bought will work just fine. The only difference between that board and this one is that we added some pull-up and series resistors to the STEP and DIR pins.

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