Overview

Marco is a GPS Bike Computer, based around Arduino. This repository contains general notes for the project as well as code.

When paired with a speedometer and a magnetometer (perhaps with other sensors?), I hope to reduce GPS polling frequency with intermediate points calculated via dead reckoning, ultimately allowing for a very low power device - <5mA on average should be achievable. <1mA would be nice, but is a stretch. Low power consumption will ultimately require different hardware.

Development will be focused towards basic stats as well as creating a GPS track. Navigation may be added, but is a low priority.

Long-term, supporting a variety of external sensors is desired - heart rate, etc. This may include direct connections to wired speed or cadence sensors. I intend to use my dynamo hub as an initial speed sensor; supporting other types is desired but is not a priority.

Roadmap

• Interface with Hardware
  • Correctly interface with sensor modules individually
  • Extend device libraries to provide necessary functionality
  • Merge hardware onto same physical platform
• Create UI
  • Add basic UI with time, distance, speed and bearing
  • Scroll through all time stats, activity stats and lap stats
• Discover limits
  • Log data to SD card
  • Add post-processing tools to convert to a GPX track
  • Score GPX track accuracy vs. reference tracks
  • Adjust polling rate and sensor selection
  • Verify performance via fuzzing for worst-case of data sheets

Hardware

For prototyping, I am using devices from adafruit:

• Arduino Zero
• GPS+SD Card shield
• Bluetooth LE shield
• Bosch BNO055 9DOF IMU with Sensor Fusion (Accel+Gyro+Mag)
• Freescale MPL3115A2 Altimeter
• Sharp Memory LCD
• Photo cell
• Buzzer
• Spring Terminal Blocks

I will update the actual hardware layout as I go.

For potential production hardware, see this spreadsheet

Wind speed sensors would be good, but I haven't seen a great solution.

Prior art (Open Source):

• http://www.avdweb.nl/solar-bike/electronics/solar-bike-computer.html
• http://www.piclist.com/techref/piclist/biketut/index.htm
• http://www.engbedded.com/veloace
• https://hackaday.io/page/428-brainstorming-an-open-bicycle-computer
• http://rockthebike.com/open-source/
• https://github.com/yock/arduino-bike-computer
• http://www.fringeneering.com/2011/07/open-source-cycling-computer.html