Overview
Landhopper was my ECE capstone project that I created with the help of Gary Bailey and Twain Byrnes.
It features:
- Solar-based self-charging capability
- Infinite battery life (when outdoors)
- 10m precision GPS tracking
- Offline map storage
- Path recording
- "Doom"
And for our efforts we placed first in the end-of-semester project competition.
Design
I was responsible for the schematic-level PCB design and evaluating energy harvesting methods, as well as writing a large portion of the firmware.
Our initial attempts at energy harvesting were mechanical, based on the swinging of the user's wrist. I designed and 3D printed a 7:1 rotary gearbox that seemed promising.
However, we soon realized that solar power would be smaller, lighter, and more powerful. Thus, we switched to a solar panel.
From there, I designed most of the system schematic. The energy harvesting circuit uses Analog Devices ADP5090 to do MPPT. The main microcontroller is an STM32L4, connected to a variety of peripherals to do battery level sensing, input handling, display, etc.
Our Rust firmware leverages async/await to communicate with the Max M10S GPS unit while also loading map images from an SD card, saving location history to a file, and playing a little raycasted Doom-mockup that I put in at the last minute. :)