Tiny CRT on a Raspberry Pi 4

We’ve seen some small CRTs in the past, including this one that Jenny List covered on Hackaday. With a diagonal of only ½″, it was designed as a video camera viewfinder, which would, of course, have optics over the lens to bring you the equivalent of a 19″ black-and-white display at a distance of about 30 cm.

While it’s always great to see old tech being brought back to life — even if just once more — before it goes into the e-waste recycler, what’s really cool is a mashup of the latest tech looking to its grandparents for support. After all, without the old tech, there could be no new tech.

Well, user @bobricius on Twitter took Jenny’s “let’s see if it works” approach and went a step further, asking “can this thing run on a Raspberry Pi?” So, he bought a complete viewfinder assembly off eBay for around 15 bucks, and, turns out, the answer is yes.
  While you’d be unlikely to find any serious use for it, given that micro OLEDs and e-ink displays are so much more efficient, the coolness factor is undeniable.

He didn’t use the optics that came with his viewfinder purchase, but it still looks amazing: Technical challenges included spending two days trying to track down how to get the analogue video signal into this tiny beast, all while being unsure if the signal was bad from the source device or the CRT circuit itself. But, once he figured it out, “it just needed a 12 V power supply and a composite signal from the Raspberry Pi,” he says.

He put together a YouTube video so we can see it in action:
If you see all the other videos on his channel, it’s definitely worth a subscribe!

It made me dust off (literally) an old Panasonic MS1 S-VHS camera that I have and remove the viewfinder (temporarily), pondering the possibilities:
  Say, that’s about the same size as a Raspberry Pi 4 in its enclosure…