@MightyPork @er1n

TBH I'd be more inclined to use a 3LR42 battery (4,5V type used in old style bicycle lights/handlamps, still available in most of Europe) and low value resistor to light the LED (and use more than one); but not only am I getting older and need more light to see things with; I can barely play piano anyway (I just about know which key/note is which) so if for whatever reason I wanted to make music within one I'd probably want to use MIDI and/or the SD card 😆

@vfrmedia @er1n Why add battery if there's juice for free? tbh I'd love to use USB instead, but it's only a device and the socket isn't powered internally

@MightyPork @er1n I am now too clumsy for some fine soldering (not much better when younger) - and I may want to use the LEDs as portable light source for other things, such as inspecting small components or reading an old Kindle (that lacks backlight) in bed.

I have a small stock of the batteries which were
cheap in bulk, can usually power 5V circuits and useful for 9v equipment where 6LF22 runs down too quickly (or the transistor radio I listen to Radio Caroline with)

@er1n @MightyPork I also have multiple surplus 230V to 12V or 5V adapters (there is literally one here on the floor next to me) but these can be source of RFI and I am the sort of chap who does odd things like listen to a 1980s shortwave receiver at 03:00 that doesn't have an illuminated tuning dial scale, but don't want to turn on every light in the house..