22 lines
1.3 KiB
Markdown
22 lines
1.3 KiB
Markdown
This device is designed to repel cats.
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In my case, it is used to scare it away from my fridge, before it opens and empties it.
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It will first detect the presence and then emit ultrasounds.
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This device uses an Arduino Nano 3.0 board with an Atmel ATmega328P micro-controller.
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A HC-SR501 PIR motion detector in repeat mode is connected to 5V, GND, and D4.
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When motion is detected (the cat is approaching) a light barrier is switched on.
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A E18-D80NK is used as light barrier.
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It is connected between 5V and D5.
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The signal pin is connected to D6.
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When the light barrier is broken (the cat is in front of the fridge) a loud (annoying) ultrasonic sound (24-25 kHz, outside the human hearing range) is emitted (using PWM).
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To make noise a piezoelectric element (without oscillator) is connected between D9 and D10.
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When the switch is released (the cat opened the fridge) an alarm is sounded (4-5kHz, audible by humans) until it the door (thus switch) closed.
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A button switch is connected between GND and D3, and placed on the door of the fridge.
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The firmware is available in the **firmware** directory.
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To flash it, use `make`.
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For a more verbose version, use `make debug` (after `make clean` if `make` has been used previously).
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Debug messages are then sent over the serial port.
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The code is well commented for more information.
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