CRT Badge Made From a Raspberry Pi and Hacked Sony Watchman

Over in the Hackster community, OSH Park, Autodesk EAGLE & Fusion 360, and Hackster are sponsoring the BadgeLove contest. The challenge is open to everyone, so submit your coolest badge design! I decided to throw my hat in the ring with my CRT Badge that I made from a Sony Watchman and Raspberry Pi.

I was inspired to build this after writing a post about Bitluni’s awesome CRT Boy project. Emily Velasco (@MLE_Online) pointed out that it’s easy to find a Sony Watchman on eBay for less than $20, so I snatched one up. The Sony Watchman was a line of portable, monochrome CRT TVs that were sold throughout the ’80s and ’90s. But, because of the switch to digital TV broadcasting, they can no longer pick up any TV signals — making them perfect for cheap hacking.

In order for it to display my name, I needed a way to get a video signal to it. Luckily, the Raspberry Pi Zero W has a built-in composite video output. The tricky part was finding a part of the Watchman’s circuit to inject that signal. It’s be done many times before, but all of the information I could find online was for slightly different models with different schematics and chips.

Eventually, I was able to find a place to tap into. The circuit works by taking the RF signal from the TV tuner and processing it with a VIF chip to output composite video to the CRT. After finding that chip, I was able to remove it. Then, I just had to solder in the composite video wires from the Raspberry Pi.

On the Raspberry Pi, I used a simple bash script to automatically launch OMXplayer on boot, make it full screen, and play my video on a loop. With video working, I 3D-printed a simple enclosure that I designed in Autodesk Fusion 360. That was hot-glued to the side of the Watchman, and the Raspberry Pi and a small LiPo battery went inside. Now I can walk around conferences with my name displayed on a badge in retro CRT style!