Glide computers tend to come in two classes:
- Consumer products like PDAs (Compaq Ipaqs etc.), PNAs (car navigators like Mio 400 etc.) and Android smartphones. These devices are rather inexpensive, but have shortcomings (sunlight readability, mounting on goose necks, often outdated hardware, access to sensor data needs special consideration)
- Specialized flight computers (like LX9000, LX Zeus, Clear Nav Display and Vario). These flight computers are panel mounted, come with sensors (vario, airspeed, etc.) and have sunlight readable displays. Their major disadvantage is the price tag they carry which may exceed the value of some older gliders.
The goal of this project is the development of a panel mounted glide computer with a sunlight readable display, that can be non-commercially built by individuals or gliding clubs for rather small money. Interfaces allow integration of sensors and extensions at a later time.
Up to now, development is funded by Akaflieg Graz – see www.akaflieg.at
The Cubieboard is a small and inexpensive development board based on Allwinner A10 and A20 processors. See http://cubieboard.org/ for more details.
Pixel Qi Display
Pixel Qi displays offer good sunlight readability at low power consumption. The PQ070W02 display is used in the two prototypes.
The adapter board serves the following functions:
- provide power for display, processor board, RJ45 connectors and extension connectors
- interface the Cubieboard LCD connectors to a FPC with correct pinout for the Pixel Qi Display
- interface a resistive touchscreen to Cubieboard connectors
- convert TTL to RS232 levels for UARTS
- provide I2C, SPI, GPIO and power at extension connectors
The RJ45 board provides four UARTS on RJ45 sockets with IGC compatible pin out. Each of the sockets power supplies is protected by an individual, self resetting fuse.
The housing is designed from sheet metal for easy manufacturing in a sheet metal workshop or on small hobby CNC machines. It gives access to the Cubieboards µSD card slot and USB connectors. The back of the housing allows easy implementation of additional connectors for extensions.
XCSoar (www.xcsoar.org) is an open software for glide computers. It´s features, fast development, huge user base, stability and portability to different platforms make it a perfect choice for a flight computer.
At the moment, two prototypes (one with A10 processor, one with A20 dualcore) are available.
At the moment, XCSoar 6.6.5 Linux/Cubieboard version is used on a Debian 7.1 image. Hardware graphics acceleration is not used at the moment.
Update the new XCSoar 6.7 alpha release allows for hardware graphics acceleration.
The future of the Pixel Qi display is unclear at the moment. The adapter board and housing could be changed for a different LCD, but in terms of sunlight readability the PQ is a class of its own.
Some small issues with component placing to be changed in a future revision (more distance between extension connectors, placing of inductor and protection diode).
Small interference between aft frame an PCBs.
Backside of panel mounting option will be added (no update to baseline design, just some additional parts required).
XCSoar on Android: needs more testing. With some Android images the map display is mirrored (infoboxes OK).
XCSoar on Debian / Cubieboard A10: Some stability issues (might be XCSoar, Debian Image, Kernel or Hardware) during flight, no hardware acceleration, slow reaction to user input – might be resolved with rewritten graphics code in XCSoar 6.7?
XCSoar on Debian / Cubieboard2 A20: Stable during 4 hours flight test, acceptable response time to user input. UARTS working on 3.4.43 kernel, but not on 3.3.0. Touchscreen device driver not yet available in 3.4.43.
Remote Control Stick
A stick mounted remote control was made from a very nice carbon stick grip (thank you Siegfried!), a small Arduino Leonardo clone and some SMD pushbuttons. The Arduino emulates a USB keyboard or mouse, any button on the remote can be mapped to a „keyboard“ key. At the moment, the basic button layout is similar to the remotes used by LX with four arrow, an Enter and an Esc button. The upper left button calls XCSoars Quick Menu, the upper right hand button gives direct access to XCSoars Alternates page. This works well for the most frequent interactions in flight, but does not allow to operate all of XCSoars features. If required, the operating mode can be changed to „Mouse“ (and back) by a button press. This is slower, but allows to operate all menus in XCSoar.
http://www.craggyaero.com/ultimate_le.htm shows some input devices for use in a glider cockpit. The „MicroTrack Handheld Trackball Mouse“ is available at Ebay and from various Chineses shops for small money. In flight it is less convenient than a remote control stick for standard tasks, but it is small enough to keep it in the gliders side pocket and complements the remote nicely.