Hardware

The hardware used in the project is relatively cheap:

• 1 esp32-WROOM-D
• 1 x GPS receiver (NEO-6M)
• 1 x e-ink display (WaveShare 296x128 Resolution 2.9 Inch E-Paper Display)
• 1 x sd micro sd card reader (kwmobile)
• 1 x 3.7v 10000 mAh LiPo battery
• 1 x waterproof switch

Considerations

The project started with the idea to use 2 Arduino Nano, one to handle the display and one to write on the SD. It was necessary given the relalively low number of available PINs on the board, so I later switched to the ESP32-WROOM-D.
The switch to the new board means I am now able to use the GxEPD2 library, which can handle the partial refresh of the e-ink screen, which it is nice since the full refresh take too long and it is visually awful.
Another advantage was that having more usable pins, it is possible to reduce the components. The first draft of the project used 2 Arduino and 2 GPS receiver to be able to show the informations on the display and also write them to a MicroSD card.
This lead to more complexity in the design and the necessity to have 2 separate firmware.

All these problems are solved using the ESP32-WROOM-D board, which has enough memory, more PINs and offer the space for future improvements (like switching to a TFT color screen, show the position in real time on a map etc. etc.)