Pololu DRV8833 Dual Motor Controller 1.2A, 2.7V-10.8V

I purchased a few of these to enable me to control a robot arm using a sketch I coded for my arduino UNO. It was easy to solder the included headers to the cards, write the sketch code to drive the motors and run the robot arm through some pre-recorded and feedback controlled movement. I wish it had a current sensor to provide motor current as input to the arduino for purposes of detecting hard stops on the robot arm.

Used to drive Tamiya dual gear motor with 3.7V Lipo and 3.3V MCU. This unit requires PWM on all motor inputs for balanced bi-directional control. Otherwise, one direction would "coast" mode while the other direction would be "brake" mode. I overlooked this detail when buying, so I needed 4 pwm outputs from the MCU. Not a concern if S/W controlled PWM or operating strictly On/Off. PWM frequency is about 700 Hz for better low speed on the motors. Of course, the unit is capable of much higher frequencies.

Used these with some micro geared motors and an Arduino and they just work. Can't really ask for much more than that :-)