OttoPi

Introduction

OttoPi is the Raspberry PI based box mounted on a sailboat. It's an interface between boat electronics and the sailor. Sailor can communicate with OttoPi by the following means:

• Bluetooth remote control
• Using third party app like OpenCPN when connected to OttoPi over Wi-Fi
• Web browser by opening http://otto.pi/ottopi URL when connected to OttoPi over Wi-Fi
• Custom application controlling OttoPI using Rest APIs

OttoPi is connected to the following boat electronic interfaces

• NMEA 0183 input (wind data from B&G Instruments)
• NMEA 0183 output (to VHF GPS input, B&G autopilot NMEA input)
• B&G autopilot controller (via remote control interface)

User facing features

• Connect an external app to NMEA TCP socket to receive/send NMEA data
• HTTP server running Web App
  • Upload GPX (WPTs, Routes)
  • Download ZIP (NMEA logs)
  • Upload Polars
  • Current nav status
  • SOG, SOW, COG, HDG, Bearing to WPT, AWA, AWS, TWD, TWS, VMG, Target VMG
  • Historic plots
  • HDG
  • Race Timer control (start/sync/stop) (Reverse handicap start)
  • Race timer countdown
  • Race timer elapsed handicap time
• Audio output
  • Angle to the mark
  • Gain/Loss vs Target
  • Race Timer
• Bluetooth remote control
  • Route selection
  • Announce a current destination ( Play/Stop button )
  • Next Route/PrevRoute ( +, - button )
  • Next mark/Prev mark ( >|, |< buttons )
  • Autopilot control
  • Tack/gybe ( Play/Stop button )
  • Up/Down 10 degrees ( >|, |< buttons )
  • Up/Down 1 degree ( +, - button )
  • Race control
  • Start/Reset Timer (Play/Stop button)
  • Sync timer (+ button)
  • Set committee boat ( >| button)
  • Set pin ( |< button)

OttoPi box Hardware I/O

• GND
• NMEA IN
• 12 V IN
• NMEA OUT
• Audio out
• B&G Autopilot remote cable
  • 1 deg up
  • 10 deg up
  • 1 deg down
  • 10 deg down
  • Auto/Resume
  • Off

OttoPI REST APIs

The formal OpenAPI definition is located at navcomputer/openapi/ottopi.yaml

Here is the high level functionality

• WPTs CRUD
  • Upload the GPX file with WPTs and Routes
• Select active WPT
• Routes CRUD
  • List Routes
• Select active route
• Show current nav status
• Show leg/legs navigation history
• Race control
  • Start, Sync, Stop
  • Reverse handicap start
  • Countdown Timer status
• Log files management
  • Download NMEA files
• Autopilot NAV functions
  • Navigate to WPT
  • Select Route
• Autopilot Vane functions
  • change course N deg
  • tack/gybe

Software components

• navcomputer/nmea_sim.py - simulator to replay NMEA log useful for development
• navcomputer
  • Listens for NMEA data from internal GPS and external instruments
  • Forwards the received NMEA data to connected TCP clients
  • Runs HTTP server to process REST API calls
  • Serves builtin Web application
  • Computes necessary nav data
• Bluetooth remote controller
  • Listens for input from remote BT controllers
  • Once the input is detected communicates with navcomputer over REST APIs

Raspberry PI installation

• Make access point https://www.raspberrypi.org/documentation/configuration/wireless/access-point-routed.md
• Install pip3 sudo apt-get install python3-pip
• install TTS sudo apt-get install espeak
• See https://www.raspberrypi.org/forums/viewtopic.php?t=136974 to rid of espeak errors
• See UART configuration at https://www.raspberrypi.org/documentation/configuration/uart.md
  • https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README
• I2C support in order to use the sensor board:
  • Enable I2C support as described here
  • Install pimoroni python library
  • sudo pip install icm20948
  • Examples how to use it are here