A Sparkfun Red-Board utilizes a LV-Max Sonar component to judge distances between the user and the robot, powering the DC stepper motor to move forward, reverse or change direction. Each motor requires around 5V to operate.
In the future, a feature using the TellMeWhen Relayr app and the Wunderbar proximity sensor will send a notification to an Arduino 2.0 BLE shield when the proximity threshold is violated, overriding the LV-Max Sonar readings.
This project wasn't finished under the deadline and therefore should be treated as incomplete, i.e. the interface between the motor and sonar wasn't completed. This project can be run either with using the sonar sensor code to read the distance sensor in or with the code running the stepper motors. Please take everything with a grain of salt and let us know about any mistakes.