We've highlighted DIY remote camera shutter triggers in the past, tearing apart headphones, computer mice and bags full of hardware to make wired triggers. Tear open a wireless doorbell, though, and you get actual wireless triggering without too much fuss.
That's not to say you won't need to do a bit of soldering to get this clever little hack done, as well as track down a MOC 3020 or 3040 chip from an electronics store or internet vendor. But the rest of the hack is a simple matter of connecting a stereo cable to the outputs on a wireless doorbell sounding unit and then to the camera itself, creating a shutter trigger you can fire off from nearly anywhere nearby with the doorbell button.
Know an easier or cheaper remote trigger solution? We wouldn't mind hearing it in the comments.
How to Make a Remote Shutter Release from a Doorbell [Digital Photography School]