Hi, I just stumbled across the Keysonic Wireless Keypad N100RF, which is an 18-button keypad with built-in rechargeable battery, and a 2.4GHz USB dongle.
Thanks to the Keystroke-to-MIDI translation capabilities in Bome MIDI Translator Pro, I could use that keypad to trigger sounds in Ableton Live and do other fun stuff with it triggering MIDI messages. And using the BomeBox, you can even do that without a computer to trigger MIDI sounds or lights directly!
I payed for this one approx. $15, but I've seen similar wireless keypads for as little as $10 which should work just the same (or better). Just make sure you're purchasing a 2.4GHz one, and not a Bluetooth keypad!
Setup The first thing I noticed is how light the key pad is -- in spite of the built-in battery. They buttons are fine, but not really high quality. Will work to some degree for finger drumming. As far as I can tell without measuring, there is a short latency, but still OK for realtime performance.
Charging is done using a micro-USB charger (same as for powering the BomeBox). The USB dongle fits into a closable pocket in the keypad for transportation.
I connected the USB dongle to a computer and loaded the Keystroke_to_MIDI_simple.bmtp project file, which ships with Bome MIDI Translator Pro and the BomeBox. That project file just maps every key to a different MIDI note, so you can start directly using MIDI learn in Ableton Live (or other DAW) to trigger your desired sounds.
Usage on Windows On Windows, it works just as expected. The only strange thing is the NumLock key: when you activate it, and Windows' NumLock is off, the keypad will enable NumLock for every button individually. So, mapping NumLock as an individual button will not work.
Usage on macOS After connecting the dongle to MacOS, it asks to identify the keyboard. I tried different ways, but in the end, macOS cannot identify this keyboard, and I just selected US keyboard. In Bome MIDI Translator Pro, the wireless keypad works generally fine, with a few exception. 1) Without NumLock, all keys work as expected, except the "0" key, which is received as the "Help" key, and the ENTER key is received as "Return". Once I updated the respective translations in MT Pro, you can use these keys, too. Note that without NumLock, the "5" key does not send a keystroke, because it is only active in NumLock mode. 2) With NumLock, all keys work correctly, except the "1" key, which is received as "Insert". Now that is really strange, but again, using MT Pro it can be mapped appropriately.
Usage on BomeBox I plugged the USB dongle directly into the USB port of the BomeBox, loaded the Keystroke_to_MIDI_simple.bmtp project file in the web config, selected the output MIDI port in the MIDI ports web config, and it works! (see the tutorial Map a QWERTY Keyboard to MIDI using BomeBox for more information on setup). You don't even need a USB hub (as usually necessary when connecting QWERTY keyboards to the BomeBox). Make sure to have upgraded your BomeBox firmware to version 1.3.1 or later.
Still, there are a few quirks: enabling NumLock causes a series of strange messages, so NumLock mode is pretty much unusable. In non-NumLock mode, everything works fine, except for the "5" key, which generally is not active in non-NumLock mode.
For example, you can connect a hardware synth to the MIDI OUT plug of the BomeBox, giving you a setup where you can wirelessly play a synthesizer without a computer. With MIDI Translator Pro, you can create the MIDI mapping you need for the wireless keypad.
More Keys? Of course, you can also use a wireless QWERTY keyboard. They're not as small and not as cheap, but work just the same.
I hope this is interesting to some users! Reply or comment here if you have questions or additional information. Thanks, Florian