Powering device from wires at door(doorbell button)?

Projects General Guidance
1

My original thought was to use the power from the 2 wires at the front door used for the doorbell. Further thought realized this is not a + and - wire. But more/less one wire interrupted by a switch to break the circuit until pressed. >:(

Is it still possible to use the 9-12v? with a buck verter for constant 5V? What about Ground?

or

Use the power at the porch light. Maybe gut a usb adaptor and install it in the lamp along with the device.

I already see it coming... Depends on what you're trying to accomplish and with what.

I want to make my own weather station "kinda-sorta". No seriously, just want to make something and be useful. So I decided I wanted to check the weather without having to open the door. Sure I could just mount a thermometer on the outside of the window, what fun is that!?
EQUIPMENT:
Wemos D1 mini
Adafruit BME280 Temp,Barometric pressure,Humidity sensor.

2

What powers your doorbell? Does it have a light?

Allan

3

Doorbells (at least in the U.S.) are usually powered by low voltage AC, possibly 12V rms.

You can draw a small amount of current from the switch wires without activating the chimes, but of course the AC will have to be rectified and filtered.

4

I think they are 24VAC actually. Can't get the cover off mine to check.

Or maybe that's my furnace.

5

Heating/AC is indeed 24VAC but AFIK, most standard doorbells are 10-16 VAC.

Here is what Home Depot advertises, at least for the U.S.

6

jremington:
Heating/AC is indeed 24VAC but AFIK, most standard doorbells are 10-16 VAC.

Here is what Home Depot advertises, at least for the U.S.

That is for new door bell transformers. Old ones are 24-30 VAC. A new lighted push button will burn out on an old transformer. (experience!).

Paul

7

Oh yeah, huh... AC-DC somewhere's around 12VAC, not critical for a doorbell but is still AC. Something again, I had not considered.

Yes there was a light on the previous one. about 3 years back, it decayed to the point it needed replaced. Was replaced with a simple button; no frills, no light. About as plain as you can get. I do remember taking a reading back then and there were only two wires. Same two wires that I had to cut a notch in the door frame when the new door was installed.

Hahaha. Laughing at myself. I just had a puzzled thought and went to check for myself.
Yes, the button is lighted!!!

Moms was the no frill doorbell she had me install. She bought it because she liked the way it looked.... What?!