Using this Pololu module and one serial output from the BASIC Stamp module, it is possible to independently set two motors to go forward or backward at any of 127 speeds. To control additional motors, you can connect multiple motor controllers to the same serial line. The Pololu controller supports a low range of voltages and comes pre-assembled; also is compatible with all BASIC Stamp, SX and Propeller microcontrollers.
Features:
- Control up to 2 motors with 127 speed selections
- Low power consumption
- Autobaud detection
- Various range in motor voltages supported (1.8 to 9.0 VDC)
- Current rating up to 2A for a single motor, and 1A for two
- Discrete size, perfect for small projects
Key Specifications:
- Power requirements: 2.5 to 5.5 VDC
- Communication: Asynchronous Serial (2400 to 19200 with auto baud detection)
- Dimensions: 0.90 x 0.45 x .12 in ( 22.86 x 11.43 x 3.15 mm)
- Operating temp range: -4 to +167 °F (-20 to +75 °C)

Downloads & Resources:
Pololu Micro Dual Serial Motor Controller Documentation (.pdf)