After various disappointments i finally understood how to find those damn wires on stepper motors. I tought it was simpler to drive bipolar motors but at the end i prefer unipolar stepper motors.. more cables but easier to drive.
Anyway... after breaking my only L293D i decided to try again with the famous ULN2803A. With some patience and low voltage (5v) i followed the previos mentioned video description and wrote down all the wire sequences of the stepper motors i have salvaged.
- OKI EM-199 (SMA6511) from epson printer
- OKI EM-154 (STK6711AMK4B) from epson printer
- OKI EM-318 (LB1847) from epson printer
- Mineba PM35L-048-HPI2 from hp printer
- Mitsumi M55SP-1N from hp printer
As you can see i only found the datasheets of the motors that i could not find the drivers datasheet. So...
From what i understand the Mitsumi M55SP-1N:
- consumes less:
- the excitation mode is the one used in the library
2-2 Phase excitation
- and i know i can use
12vto drive it.
It's the first time i use a stepper motor
I don't want to destroy my microcontroller or any other part of the circuit.
And here is the question:
by that i mean:
- the ULN2803A has already lots of protection diodes.. safe enough?
- the Mitsumi M55SP-1N datasheet says 259mA/phase*4=1,1Amp..correct? uln2803 handles 500mA per channel and a max of 2,5A .....
- powersupply of 1.25 Ampere....enough right?
- A strange thing happend .. @5v with high speed stepping the ULN2803A got hot. 50-60 deg C. normal?
If its ok (safe) .... what Capacitor should i put near the Vin of the stepper motor?
And if you think i should use one of the above stepper drivers or know more about the unknown motors, i'm happy to learn new things...
Note: Like i said i already tested all motors at low voltage & low RPM, all of them work at 5v using the above circuit except the capacitors. This on a breadboard.. now i want to solder it together. I'm new to electronics, and something that, for you, is obvious, is probably something that i don't even know.