DIY Keyboard with Logitech Unified Receiver

[bueller]

I've been doing some research on this for a while and thought I'd see if anyone else has thought of something similar. I love the idea of a bluetooth keyboard but what irritates me is wireless mice are awful for bluetooth so I'm stuck with using a Logitech mouse with their unified receiver dongle. This made wonder whether it would be possible to hook up a keyboard to MCU and have it send keystrokes to the unified receiver instead of using bluetooth.

Did a bit of searching around and found Logitech's spec for the unified protocol, still doing some research but I think it might be possible with a bit of work. Seems like their protocol is just built on the usual HID sent over bluetooth/usb with an extra layer of stuff on top for the pairing of devices and logitech stuff.

Am I the only one that thinks this would be pretty handy? I love my Logitech wireless, never need to stuff around re-pairing it whereas every bluetooth device I've ever had has been a pain in the arse.

[Pacifist]

I made a thread a while back trying to convert a wave controller to work with a direct wired board, but membranes are so hard to figure out that I gave up

[esoomenona]

Didn't someone use a wireless/bluetooth controller to connect a Model M? It wasn't a Logitech one, but it was something. Perhaps it is possible.

[bueller]

Didn't someone use a wireless/bluetooth controller to connect a Model M? It wasn't a Logitech one, but it was something. Perhaps it is possible.

Yeah I've seen those but I'm just hoping we might be able to leverage the unified receiver so we can use one dongle for two devices. Being on a laptop with only 3 usb is killer.

[esoomenona]

Just to be clear, I don't mean using some external adaptor. I mean wiring a keyboard up to a Logitech controller that has the ability to connect to the receiver built in to it. I know it doesn't allow any sort of customization, but it is something.

[bueller]

Just to be clear, I don't mean using some external adaptor. I mean wiring a keyboard up to a Logitech controller that has the ability to connect to the receiver built in to it. I know it doesn't allow any sort of customization, but it is something.

Ah that's an idea. I might have to look at buying a cheap Logitech keyboard and pulling it apart.

[krishna]

Even better might be a small (powered) circuit in a box that transceives between USB and the keyboard portion of a unifying protocol transmitter.  This way, you could plug any USB keyboard into the box and use it with your unifying receiver.

[suicidal_orange]

Any keyboard, even a cheap membrane one, is just a switch matrix connected to a chip to interpret keypresses so if you build a board with the same matrix as the logitech board had you just need to get a connector and it wouldn't notice the difference.  If you want an alternate layout you'd need to wire in some switches in different physical locations compared to the matrix so you only get one shot at making your custom layout, but that's better than none.

Membrane sheets are transparent too so it should be pretty easy to map it out

[nephiel]

I've been looking into this. Been using Unifying devices for 3 years or so, multiple devices, both keyboards and mice. In my experience, it's always performed reliably: no noticeable lag, range has never been an issue, and battery life is outstanding.

The most straightforward way to convert a keyboard to Unifying is to get a cheap Unifying donor keyboard, tear it apart and put its controller on the keyboard you want to use. Gon does it:

You can even change the layout with a little more work, once you have mapped both matrixes. But you can't reprogram it or otherwise change the layout easily afterwards.

If we could get a reprogrammable controller like TMK or Soarer's to output to a Unifying keyboard controller, it would be perfect. I wonder if a Teensy++ 2 would have enough I/O pins for that.

[suicidal_orange]

That controller board looks like it was made to be modded with those well spaced pads down the side

[nephiel]

That controller board looks like it was made to be modded with those well spaced pads down the side

That's the controller from a Logitech board - those pads on the edge are just pressed with a piece of foam against the matrix contacts on the membrane sheets, so you don't even need to desolder the controller.

[suicidal_orange]

That controller board looks like it was made to be modded with those well spaced pads down the side

That's the controller from a Logitech board - those pads on the edge are just pressed with a piece of foam against the matrix contacts on the membrane sheets, so you don't even need to desolder the controller.

How kind of them )

I can't believe this mod isn't more popular when the boards aren't much more expensive than a Teensy and it's wireless.

[bilogic]

I released code for building one https://github.com/bilogic/logitech-unifying-device although you need to use an older (vulnerable) dongle firmware. Looking for help to make it work with the latest firmware.