In the previous post I gathered information about a cartridge slide unit taken from an old inkjet printer. As I found out, the printer used a common DC motor to move the cartridges on X axis, however with the addition of an optical encoder with strip, the cartridges could perform precise movements. So, I want to interface this to Arduino. Original printer electronics such as motor drivers were of no use (proprietary ICs without public datasheets).
I had to drive the motor with a L298N H-bridge module and for the encoder I built a PCB which replaced the original one used in printer. The software is not as simple as you may think. I just can't turn on motor until the reading of encoder equals the desired position. Suddenly stopping the motor will not result in a sudden stop of the sliding block. Due to inertia, it continues to move a bit, even with the motor electrically shorted. The proper approach requires a PID (proportional-integral-derivative) control algorithm which adjusts motor speed using PWM.
The motor with optical encoder wired to Arduino
