Galileo's display modules are PDAs, specifically the Sharp Zaurus SL-6000. This device is a Linux-based PDA with a Java Virtual Machine (JVM) pre-installed. I/O ports include serial, USB, CompactFlash, and SD/MMC. It also has a built-in keyboard, which is ideal for flight planning, and a sunlight-readable touch-screen display. The picture on the left is scaled down to make this page easier to read; click it for an enlargement that shows the keyboard section open in great detail.
The display itself is almost worth the cost of the PDA (currently $699 retail). It's a 480x640 transflective device, which is impossible to find through electronics supply houses. Most color displays are smaller (320x240) and transmissive, so they provide sublight readability by simply being so bright the sun can't overpower them. This is fine for consumer devices but they're usually back-lit with Cold Cathode Fluorescent (CCFL) tubes, which can't be dimmed enough to avoid destroying your night vision.
A transflective display, on the other hand, uses some of the sun's own light to increase the display brightness when the sun hits it. This means the backlight can be less powerful, and this is ideal for night flying as the dimming range is better. It could still use some additional dimming, but that's easily accomplished by installing a tinted film on the screen protector, similar to what you might place on a car window. The display performs very well in my tests, with all but direct sunlight being just fine. Direct sunlight itself is actually OK, too, just not at the angle that would reflect the sun itself, because the gloss of the screen DOES reflect the sun. An anti-glare filter might be a good idea, too, or just an instrument panel overhang.
The Zaurus has serial port and USB connector on the bottom of the unit, and each PDA sits in a custom cradle made from fiberglass, with spring-loaded prongs on the top to keep it in position. The bottom cup and top prongs are lined with rubber pads to help damp vibration and keep the units from shifting. The bottom of the cup is just small enough to avoid interfering with the keyboard cover while still providing a firm grip.
The display connects to the rest of the network (which is a CAN bus) via a USB-to-CAN transceiver. Full details on this device, and a link to schematics, PCB layouts, and parts lists, will be posted here when the design is complete. It's a simple design, making use of an FTDI USB-to-serial converter, a microcontroller, and a CAN-to-parallel controller. The devices are all capable of operating at the full 1Mbps the bus is rated for, so there's no worry about bottlenecks. Because the transceiver is a generic USB serial device, a laptop may also be connected to the bus via an extra transceiver, to provide additional data logging, programming, or debugging facilities. Read more...
As an alternative to the Zaurus, Jeff Wilson is working on a set of robust, microcontroller-based displays that will theoretically be much more reliable than a PDA, will not require CAN bus converters, and may offer larger screens. The Galileo display applications will not run on these displays, but the sensors are designed to be compatible so it is possible to deploy the display modules interchangeably, or even mix them. Jeff is considering selling his displays pre-built, pre-tested, and ready to deploy, so visit his Web site and let him know if you would like this option so he can gauge interest levels. Note that this would also provide commercial support for a home-built-priced glass cockpit system, which no other solution can offer.