This Feather Wing was designed solely with through-hole components, which are easier to put together by hand for small runs. In the future I may make a version with SMD components as well for professional manufacture. I made this to control 5V 28BYJ-48 steppers that are easily available for ~$2-3 each. Often they come with a ULN2003 driver board, if you are thrifty you can grab the chip off the board and move it to this board saving ~50 cents per board.
This board contains:
1) Two 3-pin headers (GND, PWR, and SIG). These can be used to control a servo or additional sensor.
2) A 3.5mm TRRS port for external control
3) Two LEDs tied to digital pins
4) The ULN2003 motor driver
5) Two small buttons for user control
6) Two strategically placed holes to give physical access to the Feather M4 Express reset button and visual access to the Neopixel on that board