Glass Cockpit

The part of the project I am working on now is to make an EFIS (Electronic Flight Instrument System). This consists of 4 units, a display, a display computer, an ADAHRS (Air Data, Attitude, and Heading Reference System), and a magnetic compass. They are connected by a bus. I will be able to attach 2 buses to the display computer for redundancy. A diagram of the system is below.

...........      ...........       ...........       ...........
.         .      . Display .       .         .       .         .
. Display .<....>.         .       . ADAHRS  .       . Compass .
.         .      . Comp    .       .         .       .         .
...........      ...........       ...........       ...........
                   .    .             .                  .
                   .    .             .                  .
  CAN Bus A        .    .             .                  .
........................o.............o..................o......
                   .
...................o..................o..................o......
  CAN Bus B                           .                  .
                                      .                  .
                                      .                  .
                                   ...........       ...........
                                   .         .       .         .
                                   . ADAHRS  .       . Compass .
                                   .         .       .         .
                                   ...........       ...........
                                                           

Display

The display is mounted on the instrument panel and will also have buttons for input to the display computer. I got a small 5" monitor off of the mp3car site. This unit has a separate power supply box so is kind of complicated. It also has a touchscreen, which I probably won't use.

Display Computer

The display computer drives the display and also connects to the busses to read the data supplied by the sensor boxes.

  • ARM CPU for low power
  • USB port
  • Linux OS
  • Dual CAN controllers and connectors
  • 12V Power supply
Details

ADAHRS

The air data, attitude, heading reference system senses and encodes onto the bus the following data:

  • Pitch, Pitch Rate, Pitch Acceleration
  • Roll, Roll Rate, Roll Acceleration
  • Yaw, Yaw Rate, Yaw Acceleration
  • Total air pressure and Temperature
  • Static air pressure and Temperature
  • Angle of attack air pressure and Temperature
Details

Compass

This one is simple, provide 3-axis magnetic field strength sensor data so that magnetic heading can be calculated. Encodes the data onto the bus.

Details

Tools

  • Schematics - gschem
  • Circuit Board Layout - pcb
  • Gerber Viewer - gerbv
  • Soldering
  • USBTiny for AVR firmware programming
  • Oscilloscope - Nano V2
  • Embedded Software
    • Angstrom distribution for display processor
    • GCC for both display computer and 8-bit AVR's
    • GNU Make and qmake for project builds
    • git and Github for software configuration management
    • Qt for graphics display
    • avrdude to download firmware to boards