Using Eagle, the PCB I designed is a Varmint Detector. Varmint: noun, North American informal - a troublesome wild animal. In my case, crows and chipmunks attacking our garden. They really arent much of a problem, this is just my excuse to build a solar powered device.
Varmint Detector is a solar powered motion activated MP3 player for scaring animals out of a garden.
Scenario: animal moves in front of the detector, detector makes noise, detector triggers other detectors, lots more noise, animal flees.
The detection is handled by a common HC-SR501 PIR module.
The noise is made by a speaker attached to an 8002a mono amplifier.
The amplifier is fed by a YX5200-24SS MP3 chip.
The 100+ mp3 clips are stored on a W25Q64JVSSIQ NOR Flash chip.
Onboard loading of the NOR Flash is enabled using a LVC125A buffer chip (isolates the NOR Flash chip).
Other detectors are triggered using a RFM69CW 433MHz transceiver (also used to silence via a hand held remote).
Everything is controlled by an ATtiny84A mcu.
The power for the board is converted to 3v3 by a LM3671 DC-DC step down converter (on board).
The power from the solar panel is stored on a single 18650 rechargeable 3.7v (4.2v when fully charged) Li-ion battery.
The battery charging is handled by a TP4056 lithium battery charger module.
The panel is a single 5V 1.25W 110x69mm mono-crystalline silicone epoxy solar panel.
The detector is turned on by inserting a battery. Once energized, the unit gives the user 20 seconds to get out of the area before it starts responding to motion and/or alerts from other detectors. When something triggers the detector it will start playing a list of MP3 sound clips. The MP3 clip played is determined by where it left off, or the index sent to it from another detector. The clips will be played for as long as there is motion detected in the area. The player will stop when there is no motion for 10 seconds. When all of the detectors are playing, they are all playing the same clip (although not perfectly in-sync.) If the user needs to enter the area where the detectors are placed they can use a remote to mute the detectors. When the user leaves, they use the remote to put the detectors in standby mode. To conserve the battery at night, the detector shuts down when it gets dark.
The three button remote is a detector board without the MP3 section.
The 3D part STL files are available on thingiverse:
The Eagle files are enclosed in the next step.
Sources are on GitHub:
If youre interested in building one, the parts list and board Gerber files are shared on…
Finally, this board with a bit of tweaking can be used for other purposes, such as the remote control noted above. You could also remove the motion sensor and simply use it to remotely play MP3 clips. Or you could remove the MP3 section and use it for remote detection, such as when mail is placed in your mailbox. For another project that uses this MP3 chip see”


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