Turning your Spark into a robot is much easier with PhoBot. Made by Simon Monk, the board acts as a motorshield for the Spark Core or Particle Photon. Using a TB6612 dual H-bridge, the PhoBot can control one stepper motor or two brushed DC motors with 4.5-13VDC power and about 1A current draw per motor.
In addition, two open drain 2A MOSFET outputs can be used for things like solenoids or large LEDs. There’s also a socket for a HC-SR04 sonar sensor, and a socket breakout that can be used with 5V i2c interface sensors. The board provides 5V regulated power to Photon or Core with a max input voltage of 12V.
The PhoBot can be purchased from Adafruit for $19.95.