I am intending to create an automated scanner using a hacked robot arm (http://luckylarry.co.uk/arduino-project ... robot-arm/)
I intend to modify the system slightly, so that I can improve the wrist motor into a 0.9 degree stepper (Nanotec ST4209S1006-B) and for the turntable an 18 degree stepper (SP1518M0204-A)
Adding the steppers means I'll need an extra H-Bridge (Texas Instruments SN754410NEG4) from the Larry circuit, and - I assume - a shift controller (Texas Instruments CD74HC595M)
I may include an LCD display eventually
I've made up a basic diagram of how I think the circuit ought to look, however I dont know enough about controlling power levels with resisters etc.
Can anyone here help out by letting me know what I need to add to the circuit, or point me to an online circuit testing tool that I can design it with

