This was a quick project to house a pi inside a second-hand portable TV.
The TV housing was untouched except for the addition of two holes for the USB connectors, and so it looks pretty neat from the outside. On the inside there was a separate board for the TV-ish stuff, so I could chop that straight out. Handily enough, it left a raspberry-pi-sized hole.
Video and sound:
Pretty straightforward, just hardwired the video lead from the underside of the pi to the underside of the AV-in port on the TV. As for the audio, tried doing the same thing but for some reason it wouldn’t work. Couldn’t figure out what was wrong here, the sound was transmitted fine from the pi into headphones, and the TV sound worked fine if hooked up to something else like an mp3 player. Even weirder, using the same connection that I had originally, I hooked it up to a different raspberry pi (using the same SD card) and it worked fine. Due to frustration (and laziness) I gave up, if sound is needed the headphones will have to do for now!
Power:
Originally the TV came with a 7.4V battery pack so I had hoped to be able to use this to make the project truly portable. Unfortunately the battery seemed completely spent and so I decided just to remove it all together but there is still ample space for a new one to be reinserted. So as it is it needs the DC power input to the TV. Also on the TV is a 7V DC output, so I wired a 5V UBEC (can see it at the top of the picture) to it, outputting into the GPIO pins of the pi to power it.
I apologise if this explanation is a bit long-winded, but the upshot is it works perfectly and the screen is large enough to have an enjoyable experience!
Sorry for posting the same pics twice, the first two are smaller than the last two, and I can’t seem to get rid of them.