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Autonomous Moth Trap

Alternatives for Autonomous Moth Trap

This is the fourth post in a series:

Raspberry Pi 4 + Logitech BRIO + motion detection

The components used in my first autonomous moth trap (mostly following the Danish design, except for the LED tube) are:

The circuit design is available here.

The Logitech camera depends on a USB 3.0 connection, which requires a Raspberry Pi 4, which then necessitates a solution to vent the enclosure and use a fan. The power of this unit makes it possible to use motion detection to capture images. This has demonstrable benefit in producing time series imaging for active insects, but (on warm nights) results in images being captured almost every 2 seconds.

A sample from this model has been uploaded as a video.

Raspberry Pi Zero + Raspberry Pi HQ camera + time lapse

I wanted to test a more lightweight (and significantly cheaper) alternative that could more easily be deployed on battery power in the field.

The A3 LED light table in the original model seems to add little to the effectiveness of the system. Power is better devoted to running the moth light and the illumination from the light ring.

The Raspberry Pi Zero has significantly lower power consumption than the Raspberry Pi 4 and does not require a fan or venting. It is also compatible with the Raspberry Pi HQ camera and 6mm wide-angle lens. This camera has a larger image size than the Logitech Brio for less than half the cost and without the need for a USB 3.0 connection.

I have therefore constructed a second model using these components:

I have written a Python script (triggered as a cron job) to capture images on time lapse. The code (AMT_TimeLapse.py) is in Github along with other software and files for the project. A JSON configuration file controls various settings and the images are saved to a folder including a timestamped copy of this configuration.

I used the instructions here to add the real-time clock to the Pi: Adding a DS3231 Real Time Clock To The Raspberry Pi. The circuit diagram for this unit is available here. The number of UV lights is adjustable (3, 6 or 9).

An early result from this trap has been uploaded as a video.

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