Trip Alarm System

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Trip Alarm System

Electronic Instrumentation Project 4: Final Design Project •Circuit

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

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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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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Use a 555-Timer Circuit for the Clock

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Pulses must be slow enough to be counted Place LED’s at the outputs of the counter to show it is counting. 15 November 2003

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Logic 101 resets counter

1 0 1

0 1

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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

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Circuit 2: Holiday Lights

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Must create your own logic to make at least three distinct light patterns. 15 November 2003

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Use a 555-Timer Circuit for the Clock

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Pulse frequency should make display look like its intended purpose – holiday lights 15 November 2003

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Logic

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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. 15 November 2003

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Circuit 3: The Clapper

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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. 15 November 2003

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Note familiar components

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Microphone, 741 op amp, 555 timer, flip flop, relay, transistor as switch, and 9 volt battery. 15 November 2003

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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. 15 November 2003

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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: • • • • • •

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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

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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: • • • • • •

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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/complete.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?

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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. 15 November 2003

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