Hardware

One of the biggest challenges for the hardware is achieving weather resistance, as geocaches operate almost entirely autonomously, except for the biannual/yearly maintenance intervals. It was necessary to ensure that the device could survive this period.

Sustainable power supply is provided by a solar panel and our custom-designed PCB. The device's waterproofing is ensured by the silicone seal of the IKEA lid and the magnetic solar panel connection. Additionally, securing the electronics with a plexipanel provides secondary protection against water ingress.

To protect against mechanical impacts, the nearly 800g PETG 3D printed box and the heat-inserted brass threads and precision needle sockets offer durability. The ESP communicates with other components through I2C, UART, SCCB, and DVP interfaces.

Software

The firmware was developed in the Arduino environment and also takes advantage of the features provided by the ESP32-S3.

After waking up, the modules receive the necessary parameters, and the loading screen provides feedback on their status. While waiting for user interaction, the device runs the GNSS satellite search and location determination in the background.

Following the capture of the photo, the device connects to the 4G network to upload the image and telemetry data to our server. To make more economical use of data traffic, the photo undergoes hardware-based JPEG compression after being taken and is stored in the ESP32-S3 PSRAM until it is uploaded to the server, thus relieving the RAM.