See links to read the tutorial I followed. I’ll update a parts list soon and post better images. This circuit is half an h bridge and implements power on and forward current only (no reverse).
I need to do sone evaluation to determine if the resistors are correct and if the transitors are handling the heat.
Steelmate Slave Door Lock Actuator [ Jaycar 14.95 ]
Vinco DBL 60/70mm Deadbolt Latch Bolt [ Hildebrandt Locksmiths 12.00 ]
Piano wire [ Extreme Hobbies 2.80 ]
25mm square section aluminium [ Bunnings Hardware ]
After heading down a complex path with Arduino and a motor controller with many more features than are required I think I can simplify the build by switching to a Phidget motor controller (1064 – PhidgetMotorControl HC). Its all in one (rather than Arduino + controller), has Python (and many other) libraries, and has built-in inputs for sensors as required. The only issue with the HC is the height of the terminator block – I’m checking this at  the moment.
After a couple of goes, I have managed to turn the simple breadboard stepper driver into a simple Arduino shield.
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Continue reading Arduino shield