Gazeer 6 Sets Stepper Motor 28Byj-48 5V Dc 4-Phase 5-Wire + Uln2003 Driver Board

Product arrived quickly. Some of the headers on the PCB are soldered at a funny angle, or arrived bent but all 5 motors and drivers work.Manufacturer specifies a 64:1 gear ratio. Some people over at the Arduino forums (http://forum.arduino.cc/index.php?topic=71964.15) have disassembled the gear train and determined that the exact gear ratio is in fact 63.68395:1. My observations agree with these findings. This means that in the recommended half-step mode we will have 64 steps per motor rotation x 63.684 gear ratio = 4076 steps per full revolution (approximately).

This vendor had the best price on the 28-BYJ48 as long as you don't need the male to female jumpers. Some other vendors include the jumpers but charge anywhere between $1.50 and 3.00 more. The steppers and driver boards came in a bag; each ULN2003 board was in it's own heat sealed static bag. The packaging is not great, but it posed no problem from a practical point of view. Other vendors will ship in a re-usable plastic box, so that bag is another reason this is less expensive. But the bottom line is that they all work great. So if you don't need the jumpers and you don't need the box, this is a great way to go.

The motors are great. I used them to make a couple automated photography turntables. Though, with a 9 inch diameter disc attached directly onto the drive shaft, the slop in the motor becomes pretty obvious. It's probably about +/- 3-5 degrees. The gearing gives it pretty fantastic torque for something so small. I was able to turn the disc with 1lb objects sitting on it powered only via USB. (You'll get more power if you give it a higher current source). The boards are not that great. 2 of mine didn't work. One not at all, and one only output on 3 of the phases. Still, with the cost of these, I was fine ordering another pack to get enough boards. I would definitely use these again.

I purchased these so I could automate my curtains, but unfortunately they were not strong enough. To be fair, my curtains are rather heavy blackout curtains, so my expectations may've been a little high for these motors. That said, all of the motors and drivers work out of the bag and are still capable little stepper motors. With some design modifications (gears, lead screws, etc) these are more than capable enough for most light applications. Both the motors and drivers are unipolar and, therefore, have less torque than bipolar stepper motors. To those looking for a motor with a higher torque than these, I recommend NEMA stepper motors or some other form factors of bipolar stepper motors. If size is a constraint for you, these unipolar motors can actually be easily modified into a bipolar motor (by cutting a pcb trace). This modification will increase the amount of torque you get out of these guys, but you will need to obtain a bipolar stepper motor driver if you do so.

One motor in the five received was miss manufactured (stamped) and in pieces on arrival. Very disappointed.

Some technical stuff:* The 4 pins connected to Motor Driver In1, In2, In3, In4 need to be entered in the sequence 1-3-2-4 for proper sequencing when using the arduino Stepper class.* There are 32 steps per revolution of the internal stepper motor in 4-step mode.* There is a 64:1 gear reduction.* Therefore there are 32 * 64 = 2048 steps per output shaft revolution.* Runs just fine on 5V* The Arduino's V-Regulator gets really hot if you power the stepper from the arduino's regulated 5V. A better solution, considering the voltage-range of these motors, would probably be to power the motors with the un-regulated voltage supplied to the arduino, or perhaps a more powerful voltage-regulator. That being said, for short movements, and a low duty-cycle, they don't seem to heat-up the arduino's v-regulator.* These motors are surprisingly powerful for their small size.* Very slow, I was able to get a reliable 9.75 RPM when I cranked the speed up to "500": ( small_stepper.setSpeed(500) ) , much faster than that and the reliability (misses steps and cant move a load) goes way downhill. So don't buy these steppers for speed. Buy 'em for torque.* Code to spin it: http://arduino-info.wikispaces.com/SmallSteppersHope that helps.

I have had several installed for a couple months to automate my blinds. They are bad about staying in synch. Sending the exact same instructions to each one yields different results. You get what you pay for. Will not purchase again,

They're so cheap that it's hard to complain. As you might have guessed, there is no quality control and the boards are built very poorly. One of the driver boards even had the 5-pin connector soldered on backwards. It took me a while to realize why it wasn't working.Overall, it's pretty much what I expected.

Strong little motors, works well - but took a long time to ship.

great

Perfect for projects good price and quick delivery