I'm working on a project where I will drive two 12V 0.4A bipolar stepper motors. I am using an adafruit ESP8266 HUZZAH, two L293D stepper motor drivers and a SN74HC NAND gate. I am supplying the motor with 12V. The code that I am using is simple, rotate the motor clockwise and then counter clockwise. This code works fine at speeds greater than 37rpm, but not bellow this. What happens is that the motor will not fully rotate 360 degrees and stop, cancelling the loop. The higher the rpm, the closer the motor gets to completing the rotation. This is an issue since I am mounting an IR sensor that will pan and tilt, allowing the temperature of the room to be scanned. The speed needs to be low to allow readings to be made.
I know the L293D is not an ideal driver for this setup, but I do not understand why the motor is behaving in this manner. Thanks