Hi, I've been working on a 2d plotter that I have built from old printer parts and I've been having problems with the chip (ATMEGA168) resetting every time one of the stepper's coils is switched off
I think it may be back emf caused by the collapsing field so the solution may be to put a diode in parallel with each of the stepper's coils to eliminate the emf. However I am not really sure what type of diode to use with what ratings.
Each coil has 4.6Ohm resistance and I'm powering them with about 5 volt and my PCB supports a maximum of 1.5A per coil. The shortest amount of time that a coil will be on for is 700Microseconds. I've read that using a diode can increase switching off times, so I would like to know what kind of extra time using a diode would add, and if it's significant, any way to reduce this time.
Also if it helps I am using 4 ULN2003 Darlington array driver ICs to drive the steppers coils each coil has 3 Darlington pairs in parallel
Thank you in advance, Paul