This is a little off-track from the 3.5mm assistive button objective, but nevertheless I'd like to visit a brief moment in the project's journey when we decided that these AT buttons could also be hacker fodder:

The circumstance leading up to this abomination is pretty clear: we had to give a presentation to an audience of a few dozen, and wanted them to be able to try the button for themselves. So here enters an ESP-01 and a small RC battery.

The ESP firmware and companion desktop ticker are on github and pretty minimalistic.

Amazingly, the ESP ticker had only a few milliseconds of delay between pressing the wireless button and updating the display. That left only battery life as a design consideration, which we thoroughly tested:

(no lockout, so it just keeps spamming button presses)

Again, amazingly, the button's diminutive battery held out of over an hour of this abuse! It's enough to make me wonder if a 802.11 wireless button could be used for serious applications. Bluetooth AT buttons are already available on the market, and we found a way to make our printed buttons operate the same way, so why stop there? With the increasing popularity of LAN and IOT based home automation, a web-connected button could become quite powerful in terms of accessibility. Just something to consider..

The bluetooth buttons, also used during the presentation: