Test Pattern Generator

I was contacted by a TV repairman based in Scotland. He wanted a basic test unit that could be used to visually inspect the quality or defects on an LCD television. It needed to be battery powered and easily usable but rugged for on-the-go use. This was my solution

It's important to note, before the broadcast engineers all shout at me, that this is only for visual testing. Something like this really wouldn't be suited to use in a broadcast environment. In the case of my client, who's really only checking if it looks OK, this is more than adequate.

The unit uses a good old Raspberry Pi Zero to output various test patterns over HDMI. A rotary switch at the front allows one to quickly select the pattern one wants, and the toggle switches control an audio tone and the unit's power. The Pi can boot up from cold in about 10 seconds - and is fully isolated when powered off, not still siphoning power like some battery operated units!

The battery in question is a small LiPo, similar to one found in a phone - it will power the unit for an hour or so. It's charged and protected by the ubiquitous TP4056 module.

Last I heard from the gentleman, over a year since it was was built, the unit was still going strong.