Structured Hardware Design - Design Exercises. Updated May 2002. 

These questions can be answered in 25 minutes but longer answers
are also easily possible. Some background reading may be necessary.

Q1. A duelling game for two players tests reaction times.
Aperiodically, a light comes on.  Each player has a metal pushbutton
and must press it as quickly as possible after the light comes on.
The person who presses second, or while the light is off, gets an
electric shock through the button.  Sketch a system state diagram,
block diagram and full circuit.



Q2. An electric wheelchair has a DC drive motor for each of the two
large wheels.  Draw a block diagram of the electronic and electrical
parts of the wheelchair.  Explain how the controls work in the form of
a user manual.  Explain what functions a microprocessor might usefully
control, including safety functions.  [ To answer this, you are not
expected to do any research.  Instead, use your brain power and
knowledge of electronics to generate the design requirements, design
outline and then deduce the design details.  To alter the speed of the
motors, it is acceptable to feed them a 1 kHz square wave with duty
cycle modulation that varies from 0 percent to 100 percent. ]


Q3. Draw a block diagram of a television set.  Don't forget Nicam, Teletext
and infra-red remote control.  Show how a digital television set-top
box plugs in, of the Sky Digital or (now defunct) ITV digital type.


Q4. An FPGA is to be used to generate a sequencer for disco lights.
The FPGA will receive some pulses that are roughly in time with the
music (generated by a crude analog circuit or else by a maniac with
some switches) and generate 10 or so output signals to control the
lights.  There are also some control inputs to select the basic mode
(blackout, strobes, dark, light, pattern select etc.).  Sketch a block
diagram of the whole system and sketch the circuitry of the FPGA.  Is
using an FPGA a good idea?



Q5. A design is required to provide timing and information displays for
the international final of the table-top Grand Prix (Scalelectrix)
competition, which is to be televised by Eurovision.  The budget for
the system is fifty thousand pounds, including the sums paid to
consultants (like yourself) and the system is expected to last for
several years.  Cars will be fitted with unique active tags, as used
for counting livestock though gates on farms, and a sensor for the
tags, together with light beams for accurate car detection, will be
placed at the start-finish line and two intermediate points on the
track.  A number of display panels are needed based on LCD VGAs and a
master operator's console is needed to control the system.  Design the
system.  Pay attention to the modules needed and the wires that
interconnect them.  Give a 100 word instruction manual for the
operator. If microprocessors are used, explain why each one is needed.

(C) 2002 DJG