Project 4: Final Design Project

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Project 4 Final Design Project
Trip Alarm System

• Circuit 1 Count and Reset Circuit
• Circuit 2 Holiday Lights
• Circuit 3 The Clapper
• Project of your choice

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The Final Design Project

• Should combine concepts that you have learned in
  this class
• Ideally should involve some digital electronics,
  but does not have to.
• You have three projects to choose from, or you
  can find one of your own.

3
Circuit 1 Count and Reset Circuit

• Counts to a binary number and then resets itself
  back to zero.
• This one will count to 4. You need to design one
  that counts to 10.

4
Use a 555-Timer Circuit for the Clock

• Pulses must be slow enough to be counted
• Place LEDs at the outputs of the counter to show
  it is counting.

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Logic
1
0
1
0
101 resets counter
1

• The logic uses the output of the counter to send
  a high signal to the reset pin when it reaches
  count1
• This resets the counter back to zero and it
  counts again.

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Circuit 2 Holiday Lights

• Must create your own logic to make at least three
  distinct light patterns.

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Use a 555-Timer Circuit for the Clock

• Pulse frequency should make display look like its
  intended purpose holiday lights

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Logic

• The counter already puts out 4 distinct signals
• You must, however, add at least one additional
  gate.
• Try to use the gates in your kit or check with us
  to see which gates are available before you get
  carried away.

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Circuit 3 The Clapper

• This circuit uses a microphone to detect two
  sharp sound waves or claps.
• When the claps are detected, it switches a relay
  that can be connected to an electric device.

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Note familiar components

• Microphone, 741 op amp, 555 timer, flip flop,
  relay, transistor as switch, and 9 volt battery.

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Circuit Operation

• A single hand clap will be picked up by the
  electric microphone which is coupled through C1
  into the op amp.
• The output triggers the 555 timer which is
  configured as a monostable multivibrater.
• The trigger pulse is stretched by the 555 and
  outputs a pulse to a D type flip flop.
• Because of the three state counter arrangement of
  the flip flop, two sharp claps are required
  before it will output a high to the transistor.
• The transistor turns on the relay and any device
  connected to K1's switch contacts.
• Two more claps will clock the timer again and
  will turn it off.

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Power problem requires circuit redesign

• Components circled in yellow must be powered by 5
  volts and the microphone by 2.5 volts and not 9
  volts.
• You must make these changes.

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Circuit of your choice

• Find a schematic and build the circuit.
• Buy a kit and put it together.
• (The above circuit is a trip alarm system found
  on the web.)

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Find a schematic and build the circuit.

• Many schematics that do interesting things are
  available free on the web. For example
• Alarm circuits
• Frequency doublers and dividers
• Rain detector
• Battery charger
• Audio amplifiers
• Motion detectors
• Sites with schematics
• http//commlinx.com.au/schematics.htm
• http//www.techlib.com/electronics/index.html
• http//www.uoguelph.ca/antoon/circ/circuits.htm

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Schematic stipulations

• Try to choose a schematic that you can understand
  and uses components
• in your kit
• available in the studio
• that you are willing to buy
• You must get your schematic approved by the
  instructor for your section.

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Buy a kit and put it together.

• Many pre-packaged kits are available for sale.
  Many are inexpensive. For example
• Cliff hanger game (11)
• Battery tester kit (9)
• Coin toss kit (4)
• Rover robot kit (16)
• Solar lightening bug kit (13)
• Lie detector kit (5)
• Sites with kits
• http//www.chaneyelectronics.com/
• http//www.kitsusa.us/store/
• http//www.electronickits.com/kit/complete/complet
  e.htm

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Kit stipulations

• Try to choose a kit that you can understand and
  uses components that we have studied.
• You must get your kit approved by the instructor
  for your section.
• If your kit requires soldering, we have solder
  and soldering irons in the studio. We will set
  them up on the center table.

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Project Report

• You will not be required to do a major write-up
  for this project.
• You will be required to hand in the following
• Signed output from the circuit or a signature
  from the staff attesting that the circuit was
  working.
• A description of how the circuit works
• What are the blocks?
• What does each block do?
• Extra Credit Available see write-up for details

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Practical Questions

• You should be able to describe the function of
  your circuit
• You should be able to divide your circuit into
  blocks.
• You should be able to connect your circuit to the
  power supply and to the scope, if necessary.
• You should be able to capture the scope signal
  both as a picture and data, using Agilent
  Intuilink software
• You should be able to design your logic using
  Pspice.
• You should be able to create a truth table of
  your logic and demonstrate it works as expected.
• You should be able to describe the function of
  individual gates or circuit blocks.