URX(R) Core 75HE keyboard software
sharkfin identifies and reads the URX(R) Core 75HE. Free and open source. Use it in a Chromium browser with nothing to install, or download the desktop app for Windows, macOS or Linux. Either way it runs entirely on your own machine: no account, and the browser version makes no network requests once the page has loaded.
2 revisions of the Core 75HE ship under this name. They are on different controllers, so they are genuinely different hardware and not just a firmware bump. sharkfin does not ask you which one you have: the board reports its own device ID when it is plugged in, and the right command set follows from that.
What sharkfin does with the Core 75HE
- Command set not on file. sharkfin asks the board which one it speaks when it is plugged in, and writes once you allow it. A board that cannot say stays read-only.
- Setup. The app's Setup page allows changes and checks them one by one: keys, lighting, profiles, one remap. Your answers keep the board working on your computer, and the report they produce, sent from the Contribute tab, is how it gets an entry for everyone. See Setup.
- Magnetic switches. This board has them. The Switches tab needs the command set first; see above.
sharkfin has no drawn layout for the Core 75HE yet, so it shows a grid of the board's 128 matrix slots instead. Everything still works; only the picture is missing. You can fix that for everyone: draw the board on the app's Keys page, which checks each key against your keyboard as you go, and send the result back.
Core 75HE at a glance
| Brand | URX(R) |
| Model | Core 75HE |
| USB ID | 39ab:9016 |
| Device ID | 4175, 4248 |
| Protocol family | unknown |
| Settings writable | after the board answers, once you allow it |
| Drawn layout | no, shown as a slot grid |
| Onboard profiles | 4 |
A protocol family of “unknown” means the command set is not on file for this revision. sharkfin asks the board when it is plugged in and writes once you allow it; a board that cannot say stays read-only.
Connecting
Plug the Core 75HE in with a USB cable. Over a 2.4 GHz receiver sharkfin reads whatever the receiver relays: some carry the settings channel, some carry nothing, and the same model ships with both, so plug the receiver in and the app says which yours is. Writes need the cable. Bluetooth has no settings channel. Settings are stored on the keyboard itself, so everything you change keeps working wirelessly once you unplug. sharkfin never flashes firmware. On Linux, the AppImage and the browser build need a one-line udev rule before they can open the keyboard; the .deb and .rpm install it. And if you are hunting for a polling-rate or report-rate setting: there is none in sharkfin, because this hardware does not expose one.
If the Core 75HE stops responding
It happens: the firmware stops answering and the app says the board needs a replug. Typing keeps working the whole time. In order:
- Close sharkfin, or the browser tab. While either is open it keeps trying to reach the board.
- Unplug the cable, wait ten seconds, plug it back in. The board needs to lose power, not just reconnect.
- Fn + Home turns the lighting back on if the backlight looks dead.
- Fn + Esc, held for about three seconds, resets the board's settings.
None of this touches firmware; nothing here can leave the Core 75HE unusable.
Core 75HE revisions
| Device ID | USB ID | Controller | Family | Writable | Layout |
|---|---|---|---|---|---|
| 4175 | 39ab:9016 | ry5088_zdm_beat75_v2_core75HE_1m_8k | unknown | asks the board | slot grid |
| 4248 | 39ab:9016 | ry5088_zdm_beat75_v4_urx75_1m_8k | unknown | asks the board | slot grid |