I'm just finished the I2C motor driver board.

There is :

• 2x DRV8839 dual half-bridge driver (it can drive 2 motor in both direction, or 4 in single direction)
• 2x INA180 Current Sensor (1 for each driver)
• 4 sensor input (analog, or digital with a LM339 Quad comparator)
• Atmega168 or 328P (for I2C interface, Speed Control and monitoring)

It's perfboard/breadboard compatible (except for ICSP and UART programming connector).