This is a very simple design to support 28BYJ-48 from a Hat. Using up to 4 x ULN2003 I get exactly 7×4 PWM signals. The only challenge is the connectors as I need to use 5 pin 2.54 pitch in this case since the steppers come with this attached (the 3D use the wrong package). I am only capable of mounting 3 of the 7 connectors on the edge.