The figure above is a block diagram detailing how all included electronic parts are connected.
The system can be broken down in into three main sub-functions, each of which attempts to meet a set of design specifications and requirements planned out by the customers over at the Center for Disability Services.
• Controlling the motors for four directions of movements:
– Receive configurations from users through the touch screen (operated by an external microcontroller)
and propagate the information back to the main micro-controller.
– Configure inputs accordingly and send PWM signals to drive the motors in four different
directions: forward, backward, left and right.
Hardware Listing: Arduino Mega, SPARK motor controller, ability switch, 12V battery and audio sockets.
• Ensuring users’ safety:
– Safe-mode: obstacle avoidance and interrupts any ongoing operations if blocked by an obstacle.
– Remote kill switch: override all ongoing operations and shut down the entire system at the
supervisor’s discretion.
– Fail-safe default: check for the availability of important electronic parts before executing commands
on them. Failures in subsystems would result in complete mobility stoppage.
Hardware Listing: HC-SR04 Ultrasonic sensor, Sharp GP2Y0A21YK IR sensor, TSOP 3828 IR receiver diode.
• Display statistical information:
– Display battery level information.
– Display speed information.
Each of the sub-functions was accomplished by a combination of hardware and software solution.