Watch this video on YouTube. “Motor voltage: 24 VDC, 38 VDC (E-type). In my case, I used 12VDC power supply to the motor because this voltage level is compatible with L293D Motor Arduino Shield.

The chip expects 3.3 V logic so he made use of a MC74LVX50 hex buffer to tailor the Arduino’s 5 V. Currently he’s working on revision two of the shield, which will include SPI flash memory.