This is a bit of an odd one. Starfire UK Ltd. (from the UK, as you might imagine) put out a line of 12 “Star Badges,” which are pin badges that incorporate light-up LED eyes. I don’t have any batteries for mine, and I’m not sure it even works, so I’m not sure if they just lit up or if they flashed. In any case, each one featured a drawing of a character from Return of the Jedi with LED lights instead of eyes. It’s really rather surreal. They made Jabba and Bib Fortuna badges that I would really like to get at some point, but so far all I have is this one.
If you turn the badge over, you can see that all of the circuitry and batteries were just exposed, and this is apparently how they all were. The pin for attaching it to your clothes is just soldered onto the circuit board. There also doesn’t appear to be any on/off switch so presumably the lights would have been on as long as the batteries were inside. Something like this must have seemed pretty high-tech in 1983.
EDIT: I got some button batteries from one of my son’s old toys and tried them in here just to see if they would work, and they did. They were kind of a tight squeeze, so I don’t know if the original batteries were thinner or if the metal prongs that hold them in place got a bit bent. But I was able to get them in without too much trouble. As you can see in the video below, the eyes flash. I still have trouble believing that there’s no on/off switch. It’s very inconvenient to have to remove the batteries if you just want to turn it off. In any case, the batteries are LR44 button cells, and they go in with the flat end of the battery up.