Step 2: Super Soarer PCBSince this F-122 will be my primary work keyboard AND serve as a user-experience trial for the future SD-122/155, I wanted to enable the keyboard with more intelligence than the average protocol converter provides. However, the
Soarer converter firmware is a great base, and will be used as a starting point.
But I want more capabilities!
So I created a little custom PCB I am calling the "Super Soarer" to add some capabilities via hardware. Specifically, the PCB adds:
- Status LEDs
- NUMLOCK on/off logic for the NUMLOCK LED
- Power LED
- 90-degree pins for a reversible cable to the F-122 logic PCB
Samwisekoi "Super Soarer PCB with temporary LEDs installedThe Teensy is as you would expect, but working clockwise around the PCB there is a transistor that switches state when the NUMLOCK circuit is enabled, resistors for the NUMLOCK on/off logic circuit, resistors for the LEDs, a dim red power indicator LED, two 2-pin and one 3-pin LED connectors, and a polarized 4-pin connector that matches the terminal-out pins on the F-122 logic PCB.
Most of that is simple and obvious, but the NUMLOCK on/off logic circuit is worth some explanation.
NUMLOCK on/off logic circuitBecause this keyboard -- or really any keyboard with 104 or more keys -- does not need the directional keys on the number pad, in my opinion, the NUMLOCK key actually puts the keyboard into an error state. That is, when you press the NUMLOCK key, the number pad loses all of its numbers! Unfortunately, again, IMO, the NUMLOCK LED works backwards. I want the NUMLOCK LED to be off under normal use -- just like the CAPSLOCK LED -- but if the NUMLOCK circuit is engaged, the associated LED should light
to indicate an error condition.
The NUMLOCK on/off logic circuit enables just this behavior by lighting the LED when the NUMLOCK is OFF instead of when it is ON like it should be. However, I am aware that there may be situations where this isn't the right answer, perhaps when converting a smaller form factor terminal keyboard WITHOUT a number pad. Accordingly, the NUMLOCK LED has
three pins. Ground (to the resistor), ANTI-NUMLOCK, and regular old NUMLOCK. I made this a three-pin connector in case someone (not me) wanted to use a two-color LED to indicate BOTH possible states with different colors.
To test this build, I soldered the LEDs directly to the pins. Once I have modded the cover for the LEDs, I will remove those and make a six-pin connector and a cable that runs to the LEDs attached to the cover.
Just to be complete, here is the underside of the hard-wired PCB. Not beautiful, but fully functional and well-tested:
Underside of the Samwisekoi "Super Soarer" PCBIf anyone is interested I can publish a parts list and schematic. If many people are interested, this would be simple to turn into a proper PCB.
More to come soon,
- Ron | samwisekoi
Sig auto-typed by my GH36 LH keypad.
