When I started with the design of the cockpit one of the first To-Do's was to decide the interfaces question. There are some interfaces, specially designed for cockpit builders, on the market, e.g. Opencockpits, FSBUS, Phidgets, FDS-SYS, PoKeys56E, and MIP737 (CPflight). Just to name some of them while others might be in the pipeline and will be on the market someday. The range of flexibility and functionality varies significantly and has a big impact on the realization aspects. In 2007 I decided to start with Opencockpits interface cards and SIOC as scripting language. I did not regret this decision over the years. SIOC and Opencockpit interfaces gives a great flexibility in design and realization. The greatest difficulty you probably will get faced on with Opencockpits is the documentation and the SIOC scripting language. Unfortunately OC did not continue in further development of their interfaces. With the result that the interfaces are not 'state-of-art' anymore from the technology point of view. The thing I struggled most with was the large amount of needed USB connections, USB hubs and the constriction that the SIOC software hast to run on the that PC and not anywhere in the network.
The Migration Project
In late 2011 I launched a migration project to bring the forward panels (MIP) functionality of my B737 flight deck from USB to TCP/IP communication. The project is successfully running now for nine months and almost finished. The project results are:
-> Decision on Pokeys56E interface as the new standard for my B737 homecockpit
-> Development of the software FSSymphony as smart interface between PoKeys56E,
Project Magenta, flight simulator core software (FS9, FSX, Prepar3d), and some add-
-> Hardware migration from Opencockpits Mastercard to PoKeys56E interfaces
-> Completion of the integration and system tests
The hardware migration, integration, and system tests were executed step by step over a periode of some weeks, with only short down times of the flight deck.
Replacement of the OC Relais Card will probably be the next step .
In my eyes the combination of PoKeys56E interfaces together with FSSymphony is the most flexible solution for cockpit automatisation. With 2 PoKeys56E cards in combination with FSSymphony I manage the following:
|- 51 Digital inputs (switches, rotaries, pushbuttons)|
|- 30 Digital outputs for annunciators|
|- 6 Analog inputs for brightness control of INBND, OUTBND display units, upper and lower EICAS|
|- 4 Analog inputs for brightness control front panel backlit, AFDS flood light, and background light|
|- 4 PWM outputs for brightness control (see above)|
|- 1 PWM output for brake pressure gauge (servo)|
|- 1 PWM output for flap position indicator (servo)|
|- 1 PWM output Master DIM control|
|- 2 Encoder inputs for SPD Ref and N1 Set|
2 PoKeys56E located in the center electronic compartment
I used 8 channel UDN 2981 A source drivers to connect the LED's in a common cathode wiring concept. In this way I could avoid to re-wire my MIP. The only drawback with this solution is, that I had to replace some of the LED pre-resistors to a lower value, because with a 5V supply the UDN 2981 A delivers approx. 3.8V with output state on 'high'. However this was not such a big deal. Material costs for 5 pices of UDN 2981 A + connectors + board less than 30.- EUR. Labor time 1.5h.
Interface board with 8 channel UDN 2981 A source drivers for LED's
Overview interface design, FWD Overhead, AFT Electronic Panel, Forward Panels and other control functions. The illustration does not reflect the current design regarding the MIP interface. For the MIP the OC master board was substituded by 2 PoKeys56E cards.
OpenCockpits (Deutschland): http://www.opencockpits.de/
FLIGHTDECK Solutions (FDS): http://www.flightdecksolutions.com/
CP Flight: http://www.cpflight.com/