I made a thing. Surplus Flight Control Keypad, rewired to USB, powered by a Teensy 2.0, and mounted to VKB Gunfighter.

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MelkorsGreatestHits
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I made a thing. Surplus Flight Control Keypad, rewired to USB, powered by a Teensy 2.0, and mounted to VKB Gunfighter.

Postby MelkorsGreatestHits » Wed Jun 12, 2019 0:11

Completed project photos here: https://imgur.com/a/qXPunGN

Features (in addition to the joystick):

Alphanumeric keys (A-Z, 0-9), period, minus, slash, F1-F7, Esc, Enter, Backspace;

14 Joystick/gamepad buttons;

2 slider axes (one rotary, one on/off);

USB connection.

I took this surplus aircraft flight control keypad by Rockwell Collins, converted it for plug-and-play use via USB, and mounted it around my VKB Gunfighter & Kosmosima. Googling around suggests this was installed in a wide range of military aircraft, including the C130 and Coast Guard helicopters. Perhaps one of you might recognize it and let me know if that's true?

The new guts are powered by a Teensy 2.0 board. The keys are wired internally in a matrix connected to a standard 37 pin connector on the back of the keypad. Each key is connected to a unique pair of output pins. It was pretty simple (if time-consuming) to map out the matrix.

On the programming side, I had to brush up on the past 15 years of programming (the last time I did any programming was on my TI-82 in high school math class). The Teensy 2.0 board has a few libraries (programs are called libraries now?) that were close to what I needed that created a button matrix and exported the input to the computer as a keystroke. It was mostly just a matter of transferring the map of the internal matrix to the one in the program and setting up a few other parameters to match my specific circumstance.

Some of the keys (like the arrows at the top and some of the navigation-specific ones toward the bottom) don't have keystrokes to map to them, so I created and mapped these to 14 joystick buttons. I also made the rotary BRT knob a single-axis slider and the on/off latching knob an axis that is either at 0% or 100%.

The US patent I came across for the keypad suggests that the keypad buttons originally lit up when installed on an aircraft. I found the pins that drive the lamps but I couldn't get it to work when powered by the 5 volts provided by the USB. All things considered, this is a minor disappointment I can live with.

I had to cut the top bar of the window off of the keypad in order to install it low enough on the joystick so that it doesn't interfere with its full range of movement. The keypad is resting on top of the Gunfighter base and is screwed down onto the plastic and aluminum enclosure with the original screws. The enclosure slides down on top of the joystick and the base is screwed onto the metal base like usual.

CrypticVillain
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Re: I made a thing. Surplus Flight Control Keypad, rewired to USB, powered by a Teensy 2.0, and mounted to VKB Gunfighte

Postby CrypticVillain » Wed Jun 12, 2019 20:45

Interesting nice work.

blatherman
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Re: I made a thing. Surplus Flight Control Keypad, rewired to USB, powered by a Teensy 2.0, and mounted to VKB Gunfighte

Postby blatherman » Fri Jun 14, 2019 6:48

Very similar to the radio control head on the B-1. The button labels are slightly different, but the manufacturer (Rockwell Collins) is the same.

MelkorsGreatestHits
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Re: I made a thing. Surplus Flight Control Keypad, rewired to USB, powered by a Teensy 2.0, and mounted to VKB Gunfighte

Postby MelkorsGreatestHits » Fri Jun 14, 2019 21:04

Thank you for this. I'm looking around for another piece of gear to repurpose for my other stick and you've given me something to search for.


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