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Topic: Radio on door bell (Read 237 times) previous topic - next topic

Linor

Hello,

I would like to connect a radio transmitter to my door bell (inside). My idea was, that at the time there is power (230v?) on the bell, the radio transmitter should send once or in intervals a signal.

What components should I think of to realize that kind of project?

I'm willing to read and learn, but I have no idea what electronic parts to look at.

Thanks for helping me!

DrAzzy

Most doorbells are 12VAC or 24VAC so that it's not classified as a hazardous voltage and they don't have to be careful with it. At least in the US.

You need to at the very least determine what voltage it's running at. From there, you'd need to find an appropriate way to get low voltage DC power out of that.

Commercially, radio doorbells are very common - but they use a battery in the transmitter (their sales pitch is that you don't have to run wires - the fact that the doorbells don't ring seems to be a detail).
ATtiny core for 841+1634+828 and x313/x4/x5/x61/x7/x8 series Board Manager:
http://drazzy.com/package_drazzy.com_index.json
ATtiny breakouts (some assembled), mosfets and awesome prototyping board in my store http://tindie.com/stores/DrAzzy

aarg

If you bypass the transformer, you're basically just looking at a switch that you could connect to an Arduino input in the standard way. You would disconnect both wires from the transformer, and join them.
  ... with a transistor and a large sum of money to spend ...
Please don't PM me with technical questions. Post them in the forum.

DVDdoug

#3
Feb 06, 2016, 12:19 am Last Edit: Feb 06, 2016, 12:28 am by DVDdoug
A normal home doorbell runs off a 16VAC transformer.   Do you already have a doorbell?

If you don't already have a doorbell, there are lots of options once you "go electronic" (such as using a little DC buzzer or a speaker).

If you really have a 220VAC bell, you can use a relay.   A regular electro-mechanical relay usually needs a driver circuit (or you can get a board with a relay and a driver), or you can drive a solid state relay directly from the Arduino. 

There are two reasons you need a relay....  A relay isolates the Arduino (and you!) from the line voltage, and it allows you to control a large voltage & current with a small signal.

You can get RF receiver/transmitter shields (add-on boards) for the Arduino, but you'll need to power the Arduino.    If you are going to run wires for power, it's probably not worth going wireless.  Otherwise, you'll need a battery.

Of course, you'd need two Arduinos (a transmitter and a receiver).    If it was me, I'd go to the home improvement store (or go online) to see what I could buy...   Unless you really-really want to build it yourself.


Paul__B

#4
Feb 06, 2016, 05:49 am Last Edit: Feb 06, 2016, 05:50 am by Paul__B
Save yourself the trouble!

Get a ring!


Or for lower tech, plain wireless doorbells cost about $10.

Frostline

It really seems to me the OP is wanting a signal generated when the already installed doorbell rings.
Possibly to activate a lamp for a deaf person or to activate a video recorder when the bell is rung or any other number of uses.

aarg

Sure, but without any reply from the OP, who knows?
  ... with a transistor and a large sum of money to spend ...
Please don't PM me with technical questions. Post them in the forum.

Linor

Hey all,

thank you very much for all your help so far! Sorry for my delay, just haven't good that much time atm.

Frostline is right, I do want a signal generated when the already installed (wired) doorbell rings. A separate Arduino truely isn't a so good idea. But I've heard of Attiny85 - that should also work, wouldn't it?

What I am going to do next is to check the voltage - it should be 12 to 24 Volts as I recall from DrAzzy. I have not seen any transformer, yet - but I'll have a look.

Afterwars I will connect a relay with the two wires from the doorbell (leaving the doorbell itself connected) and connect my Arduino/Attiny85 onto the relay? Is that kind of the idea?

Again, thanks for helping!

Linor

Noobian

Hey all,

thank you very much for all your help so far! Sorry for my delay, just haven't good that much time atm.

Frostline is right, I do want a signal generated when the already installed (wired) doorbell rings. A separate Arduino truely isn't a so good idea. But I've heard of Attiny85 - that should also work, wouldn't it?

What I am going to do next is to check the voltage - it should be 12 to 24 Volts as I recall from DrAzzy. I have not seen any transformer, yet - but I'll have a look.

Afterwars I will connect a relay with the two wires from the doorbell (leaving the doorbell itself connected) and connect my Arduino/Attiny85 onto the relay? Is that kind of the idea?

Again, thanks for helping!

Linor
ATTiny85 is a good choice but you need an Arduino to program it if you want to do it the easy way, or a separate programmer.Besides there is a chance that ATTiny won't support all the functions a regular Arduino does.

Why not go for a Digistump (aka Digispark) or a Small Lilypad if size is your main concern.

Just be careful when dealing with 240V AC electrical items that have no Grounding/Earthing.

aarg

Yes, a relay or an optoisolator circuit will convey the signal very well to whichever processor board you choose.
  ... with a transistor and a large sum of money to spend ...
Please don't PM me with technical questions. Post them in the forum.

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