Hello pavilion5
When the contact sensor’s magnet is brought in contact with its sending unit the LED flashes once and stays off as long at the magnet maintains contact. When the magnet is taken away from the sending unit (sufficiently far) the LED flashes once and stay off as long as the magnet stays sufficiently far enough away. The doorbell switch needs to make and keep contact or break contact and stay open. That continuous contact or continuous open is what the magnet’s changed proximity provides. A simple one-way (single-pole) switch will mimic the behavior of the magnet. My hunch is that the connecting wire should be 24 to 28 AWG.
When I was preparing to modify a contact sensor by removing its reed switch and soldering two wire leads where it used to connect to the circuit board, I did a test. Before removing the reed switch, I shorted out the reed with a little piece of wire and held the short in place, the LED flashed once and remained off. When I removed the short the LED flashed once and remained off. This is what the magnet does. when it is close it shorts the reed switch and when far enough away it does not short the reed switch. An easier way to do this test is to remove the adhesive on the sending unit’s door and insert a small diameter jumper wire through the two holes in the case door that line up with the soldered ends of the reed switch (probably for production line testing).
I think if you can find a doorbell switch with the action of a very small one-way (single-pole) type, your battery drain problems will go away or at least be significantly less.
Victor Maletic.