The figure above is a high (very high) level block diagram which illustrates the design requirements and constraints that define my project. Following the figure is a set of design specifications which were developed after a conversation with Mr. Luther and Mrs. Shemo from Langan Center for Disability services.
All of the below specifications were carefully detailed as to ensure that the device will be safe and easy to use for children.
Performance
• The Wild thing® controller needs to produce individual outputs for each motor, as they are independently
powered.
• The vehicle must be able to move forward, backward, steer left and steer right, and brake. Speed
acceleration and deceleration need to be smooth to prevent jerky movement.
• TheWild thing® controller needs to have a usable administrator tool, with which users can modify
the inputs being used, how the inputs control the two motors, the type of inputs, and the maximum
speed of the vehicle.
Compatibility
• TheWild thing® Controller must be able to interface a variety of standard ability switches, whose
signals are transferred through a 3.5mm jack plug.
• The controller needs to be adjustable to specific user needs.
Debugging
• The controller needs to have a debugger display available (on the vehicle itself) to the administrator
users, which will display important information about the current system, such as: Battery
level, current speed, current signals outputted from the switches.
Safety
• The controller will use a series of proximity sensors to avoid walls and obstacles. This will be
activated in a mode called safety mode, which can be turned on or off via the administrator tool.
• An emergency stop button can stop the vehicle once pressed.
• Failure in any subsystems must result in mobility stoppage.
• A remote controller, which can act as a kill switch, must be available for supervisor. The controller
should be able to control the device just like a normal set of ability switches.
Energy
• The system should provide enough power for at least 1:5 hour of operation, both indoor and
outdoor.
• There should be a notification when the batteries run low, and the device would be slowly halted.