Introduction
XCSoar is an amazing software for sailplane, hangglider and paraglider. But it laked the proper hardware with the following features:
- sun readable ( eink)
- usable with gloves (anything but capacitive)
- long battery life
- running android/linux
- GPS and/or bluetooth
- dirt cheap
The Kobo Mini (unfortunately no more retailed) appears to be meeting all theses requirements exept the GPS.
Hardware
You will need for this mod:
- Kobo Mini reader
- GPS module with serial output
- switch (optional)
- extra battery (optional)
- of course an iron solder, solder wire and a piece of flat ribbon cable
Take your original Kobo Mini:
(By the way, the way Kobo handle the first boot is just crap: I don’t want to register my device online or anything, just to drag and drop my own ePub books)
Backup the micro SD card (command for linux only, sorry)
dd if=/dev/mmcblk0 | gzip > ~/kobo.img.gz
Solder the MTK3339 GPS breadboard (with a piece of flat ribbon cable such as IDE, Floppy, etc..)
KOBO to GPS MTK3339 wiring
KVCC <-> VCC TP2 <-> BACKUP (TP2 is just below the battery connector) RX <-> TX TX <-> RX GND <-> GND
Don’t forget to cross RX<->TX and TX<->RX
Just in case you wondered, yes the BACKUP does accept 4.2V, not just 3.3V (have a look on the MTK3339 datasheet )
The spacer from Thingiverse (thanks to matbhe for the design) printed by Shapeways for just 22€ incl P&P in about a week.
Take the screws, M1.6x7mm (my 10mm were too long, I had to cut them with a pair of pliers)
All fit snugly, even the original back cover.
Looks nice, no?
Add ON/OFF button to switch the GPS power (a simple SMD switch to the GPS’s VCC)
So I can still use it as a regular eBook without draining the battery and without the blue led blinking in the dark.
A piece of double side tape holds the module in place.
The switch is accessible with the nails as it’s quite recessed.
Add a label for even more clarity.
Software
Download XCSoar KoboRoot.tgz: http://www.xcsoar.org/download/data.html
And the maps: http://www.xcsoar.org/download/data.html
Download hotspot (probable thermal) as waypoints (wpt format), and set the file in waypoints configuration): http://thermal.kk7.ch/
GPS configuration
Configure the GPS to /dev/ttymxc0 at 9600bauds and “GPS waiting for fix” should appear, note that the first fix can take up to 15min (30s later on, thanks to BACKUP power supply to keep the RTC and ephemeris)
And here you are, you have a comp GPS for less than 100€/$/£ for paragliding/sailplane, in about an hour of work.
Next update to come:
- 4200mAh battery to be received
Integrating a variometer such as leBipBip (solar variometer for 89€) would be perfect, as the firmware is opensource (Git) and it as serial connection on the board with NMEA pressure output:
leBipBip PCB board has a 0.05″ header with VCC,GND,RX,TX on the top left side
Misc links
XCSoar forum: http://forum.xcsoar.org/viewtopic.php?f=3&t=1242
GPS mod found on the internet: http://www.extreme-nature.de/?p=9114
M1.6×10 screws: http://www.ebay.co.uk/
Commercial GPS mod base on this device: http://www.goflyinstruments.com/gofly-project-v4/
XCSoar forum about this mod: http://forum.xcsoar.org/viewtopic.php?f=3&t=1404&start=10
Bigger battery, 4200mAh: http://www.aliexpress.com/snapshot/6090133291.html
