My front door is fitted with a wireless door bell. It’s pretty simple, no channels or anything, and 8 tunes. The middle door is fitted with a magnetic switch, which is part of a complete wireless burglar alarm system.

When I got home this afternoon, I walked through the front door. Fine. The alarm wasn’t set. Fine.

When I opened the middle door, which has a magnetic door sensor attached, the doorbell started playing a tune, not one of the tunes that it can be set to either.

Since then, every time the door with the magnetic switch attached opens, the doorbell makes an annoying beeping noise, which also isn’t one of the options.

Batteries are out now, so everyone’s happy, but why are these interacting now, when they haven’t at all before, and why does the door bell play a tune that isn’t one of the available options?

Ideas welcome…