This post is about a kind of project which is closer to what I did back in 2012-2013. Which reminds me that I forgot to celebrate the 10 years anniversary of this blog (I opened it roughly 12 years ago).. Incredible stuff
In any case, the other day I stumpled upon an old rotary phone, a red one, to be precise. I couldn’t help but admire it’s beautiful desig, so I bought it for 35 euros (probably could have found it cheaper, but it was in good condition.
I immediately knew what I wanted to do with this: I wanted to turn it into my house intercom.
I got to work, and disassembled my current intercom first, just to commit to the project. Actually no, but I needed to get a look to the connections to make sure it would work, and after finding out it was probably easy, I dived into the thing – and committed to the project anyways 🙂
I’m not gonna go into too much detail but the current intercom was providing 5 separate lines:
- shared + signal
- line for outbound audio
- line for inbound audio
- line for buzz
- line to open the door
On the other end, the phone was using just three lines in input, I didn’t reverse engineer exactly what they were doing, but internally the phone was quite simple and the different components were easily visible:
- the rotary mechanism
- the ringing mechanism
- the receiver connections
- the switch to cut the connection when the receiver rest in place
I started to hack around some connections, main pain points were:
- to get the switch to cut out input and output to the receiver, I needed this to avoid the intercom to be active at all times (it would have been broadcasting continuously the audio to and from the outside)
- try to have the ring work instead of the original buzzer coming on my original intercom (failed)
- to get the receiver connections right (colors can be misleading)
- understand how to open the door (there was no opener button on the phone, of course)
In the end after a couple of tries I got everything working nicely, using the original buzzer (unfortunately not the beautifully sounding one of the phone) and the rotary mechanism as a button to open the door – exactly, when you turn the rotary selector the door opens. The connection and cable in the next picture is hopefully just temporary while we figure out how to rearrange the rest of the room.. but I love the result
Live test #10 (or more):
Happy 12 years anniversary (more or less) to this blog!