User manual

ECE 477 Final Report Spring 2004
grounding the LCD case since it requires a slightly higher bias supply. This will ensure that no
shorts or excessive currents will cause harm to the user. Also, it is necessary to pay close
attention to the RF sections of both the base unit and the remote unit in order to prevent
interruption of service to any other FCC certified devices. This means that these units must be
designed such that there are little or no spurious emissions. This thought must continue into the
design of the digital section in order to prevent any digital noise from being transmitted. Next,
when designing the remote device, it is expected that the circuit construction and packaging will
be able to stand up to adequate shock since it will be used by an untrained end user. This
requires that it is physically able to withstand being dropped from heights in excess of five feet,
which in turn requires special attention to component selection and packing layout. The case
should also be designed so that it is water proof. This will prevent any accidental spills from
causing the device to fail. In addition these packaging requirements, the packaging should be
designed for ease of usability since the end user will most like have little or no instruction on its
use. This will ensure that the remote device will serve its function and prevent frustration and
provide its intended services. Finally, completing a reliability and safety analysis (such as in
homework nine) before the product is expected in the market can add additional insight into the
ethical impact of the system.
After the initial design phase, the software development and design phase must be
completed is such a way as to prevent any unexpected glitches in the operation of the device.
While it would be possible to ship the device with software that provides basic functionality,
additional software development can greatly reduce the likelihood of device malfunction and
improper usage. In this stage it is important to test all software functions and ensure that the
software can handle all user inputs (even unexpected ones) with out failing. This can prevent
problems such as locking up when a user presses buttons in an unexpected combination or
getting stuck in a look where food items may be ordered over and over. In addition, by adding
built-in self tests, external hardware can be checked by the microcontroller to ensure proper
functionality of each attached section. These tests can include things suck as a power on self test
where the microcontroller can attempt to communicate with all hardware and when a failure
occurs an error message can be displayed. Other tests can check for low power during operation
and verify that the RF section is within range. Again, the results could be display when there are
errors thus preventing the end user from using a malfunctioning device.
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