This is the bill of materials for USV-01, based loosely on my previous blog post “A Base Hardware Set for USV Control”:

# Item Unit Price / £ Unit Mass / kg Qty Total Price / £ Total Mass / kg
1 HobbyKing Marine Scott Free Offshore Racing Deep V Racing Boat 730mm ARR 108.57 1.2 1 108.57 1.2
2 Turnigy 4000mAh 2S 30C Lipo Pack 12.86 0.254 2 25.72 0.508
3 FrSky X8R 8/16Ch S.BUS ACCST Telemetry Receiver W/Smart Port 22.87 0.017 1 22.87 0.017
4 Raspberry Pi 3 32.00 0.045 1 32.00 0.045
5 CJMCU uBlox 6M GPS & HMC5883L Compass module 9.66 0.02 1 9.66 0.02
6 USB Servo Board ∗∗ 15.47 0.01 1 15.47 0.01
7 Edimax EW-7711UAN Wireless nLITE High Gain USB Adapter 17.87 0.03 1 17.87 0.03
8 Pololu 4-Channel RC Servo Multiplexer 6.86 0.01 1 6.86 0.01
Total: 239.02 1.84

∗ I’m using a Raspberry Pi 2 in my build because I had one lying around, but if you’re starting from scratch there’s no reason not to go for version 3. Note that while the Raspberry Pi 3 has on-board WiFi, its antenna is tiny, so I would recommend using a WiFi USB dongle with a large antenna anyway.

∗∗ Currently, my build is slightly different in that it uses the GPIO-mounted version of this, not the USB version. The disadvantage of this is that it takes up the Pi’s UART, so a separate USB to UART adapter (CP2102) is required to communicate with the GPS. This is just because I had the bits lying around so could save some money—if starting from scratch, I would use the part listed here.