Arduino -> i2c -> attiny85 -> 595 s/r -> uln2003 -> 5 wire unipolar stepper

Projects General Guidance
1

I've been thinking about a project that controlled an attiny85 via i2c which in turn connected to a 595 shift register and from there to a uln2003 connected to a unipolar stepper. Seems in theory it should work but maybe timing would be a problem.

I'm thinking pins a4 and a5 on the uno to pins 5 and 7 on the a85
Then pins 2, 3 and 6 to the clock, latch and data on the 595
Then pins 15, 1, 2, and 3 from the 595 to the uln2003 1, 2, 3, and 4 pins
Then pins 16, 15, 14, and 13 to the stepper.

Also, I don't know if the stepper library could be made to work on the a85. If not I could probably bit bang it.

Sorry, I can't do a schematic at this time. (On the iPad)

Does anyone know of this being done or a reason it won't work?

2

I do not see any value. a 4988 stepper driver will take two pins, be much stronger, is a chopper driver, so will deliver vast amounts more power, and cost less than 595 and 2003.

the 4988 and attiny85 would be a great combination

3

Well I guess the value would be that the 4988 will not work with a unipolar stepper motor. I use them quite frequently with bipolar. If you know of a way to use the 4988 with a unipolar stepper, please let me know. I've looked....a lot.

I might also mention this is a five-wire stepper, so I can not modify the common.