The Solar Wanderer is a solar powered autonomous small boat. It is very much inspired by the Microtransat Challenge and https://www.bluetrailengineering.com/fun-stuff. The design principle is that whatever can go wrong will go wrong, and I'm not great at finishing projects, so it has to be as simple as possible. This means just solar, no sails.

• Large 100W lightish solar panel (£29.40 eBay)
• several (six?) two litre fizzy water bottles for bouyancy
• Raspberry Pi Zero 2W (£15 Cambridge shop)
• Power bank with pass-through charging, claims 10400mAh (£9 eBay)
• 12V Underwater Thruster Motor 3 Blades (£14.72 eBay)
• SIM800L 2G GPRS module (eBay)
• GPS6MV2 GPS module (eBay)
• HMC5883L digital compass (eBay)
• USB UART for second UART (£2.39)
• 1p mobile SIM (£1)

Prices above include delivery. The aim is to be under £100 for school projects. Currently about £80.

The aim is to keep the Pi Zero on all the time and maintain GPS tracking. The mobile data connection may come up once an hour to sync position if in range of a 2G mast. The two thrusters are only powered when the sun is up (roughly 17h/day in UK at summer solstice).

Details:

• Self righting - powerbank or other ballast along with top buoyancy
• If no power off then DietPi else Raspberry Pi OS Lite readonly
• Real time clock to come from GPS via gpsd
• 2G antenna to be on the top of the pyramid (with top buoyancy)
• Call home with position every hour? Allow ssh in?
• Camera? Or will this be too low down?
• Some watertight box for all electronics
• Filter historic GPS to get direction, match that with the digital compass
• Pulse width modulate the power to the thruster with two FETs controlled by GPIO