1. Project 4: Final Design Project
Trip Alarm
System
Project 4: Final Design Project
Circuit 1: Count and Reset Circuit
Circuit 2: Holiday Lights
Circuit 3: The “Clapper”
Project of your choice

2. 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.
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Electronic Instrumentation

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.
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Electronic Instrumentation

4. Use a 555-Timer Circuit for the Clock
Pulses must be slow enough to be counted
Place LED’s at the outputs of the counter to show it is counting.
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Electronic Instrumentation

5. Electronic Instrumentation1
Logic 1
101 resets counter 1
The logic uses the output of the counter to send a high signal to the reset pin when it reaches count+1
This resets the counter back to zero and it counts again.
15 November 2003
Electronic Instrumentation

6. Circuit 2: Holiday Lights
Must create your own logic to make at least three distinct light patterns.
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Electronic Instrumentation

7. Use a 555-Timer Circuit for the Clock
Pulse frequency should make display look like its intended purpose – holiday lights
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Electronic Instrumentation

8. Electronic Instrumentation
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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Electronic Instrumentation

9. Electronic Instrumentation
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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Electronic Instrumentation

10. Note familiar components
Microphone, 741 op amp, 555 timer, flip flop, relay, transistor as switch, and 9 volt battery.
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Electronic Instrumentation

11. Electronic Instrumentation
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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Electronic Instrumentation

12. 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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Electronic Instrumentation

13. Electronic Instrumentation
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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Electronic Instrumentation

14. 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:
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Electronic Instrumentation

15. 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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Electronic Instrumentation

16. 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:
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Electronic Instrumentation

17. Electronic Instrumentation
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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Electronic Instrumentation

18. Electronic Instrumentation
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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Electronic Instrumentation

19. Electronic Instrumentation
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.
15 November 2003
Electronic Instrumentation