WHEN you get ready for a bit more torque and want to set up something more akin to the basic CNC we all know and love, there is a simple unipolar to bipolar “hack” you can do with those little motors and they IMHO become imminently more useful. You then ditch the little ULN driver boards and use our beloved stepstick drivers, A4988 or DRV8825. I’ve used these little motors to build several light-weight printed Z-axes for my laser machines.
The hack is simply cutting one trace under the blue plastic cover, snipping and removing the unnecessary 5th wire, and rearranging the pins in the connector to match the stepstick driver outputs…
The electronics then becomes similar to this inexpensive CNC board… a Nano (loaded with Grbl or custom) and 2 or 3 A4988 or DRV8825 drivers to match the number of “axes”…
or this 2-axis breadboard version, which used an Uno with a couple of DRV8825…
And you come up with something “useful”. I use it almost every day…
– David