How to Build Motion Sensors
You've seen it in the movies -- the secret agent attempts to navigate through a myriad of obstacles, getting closer and closer to his goal, only to set off an alarm he didn't even see: the motion sensor. The motion sensor works by measuring the amount of infrared energy in an area. Too much infrared energy and the motion sensor turns on. A motion sensor will usually turn on either an alarm or a light. Does this Spark an idea?
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Things You'll Need
- 9-volt battery clip
- Wire
- Polyblock
- PIR sensor
- 9-volt alarm
- 9-volt battery
Instructions
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1
Use one wire to connect the positive end of your 9-volt battery clip to the positive terminal of the Polyblock. Repeat this process for the negative end of your 9-volt battery clip and the negative terminal of the Polyblock.
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2
Attach the red wire that comes out of the PIR sensor to the 5-volt terminal on your Polyblock. Attach the black wire that comes out of the PIR sensor to the 0-volt terminal on your Polyblock. Finally, attach the yellow wire that comes out of the PIR sensor to "I2" on your Polyblock.
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3
Slide the function switch on your Polyblock to the 0010 marking. This setting makes sure that your motion sensor stays on even after whatever triggered it has left the area.
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4
Use wire to attach the the V+ connector on your Polyblock to the positive lead on your 9-volt alarm. Use a separate wire to attach the V- connector on your Polyblock to the negative lead on your 9-volt alarm.
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5
Attach the 9-volt battery clip to the 9-volt battery. This will provide power to your motion sensor. Whenever someone enters the area, the alarm will sound. You can calibrate the length of the buzzer by turning the trimpot on the Polyblock clockwise for a longer sounding alarm, or counterclockwise for a shorter sounding alarm.
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Tips & Warnings
Instead of using an alarm, you can attach a 9-volt light to the Polyblock for a quiet motion sensor.
References
Resources
- Photo Credit Jupiterimages/Comstock/Getty Images
