I used to work in Telecoms and wired many of these phones. The normal power supply would have been 50 volts over the 2 line wires. Ringing was 75 volts 25Hz ac. The line loop resistance would be anything from 200-1200 ohms. The 4 wires were for line, bell and anti tinkle or earth. If there were more than one phone, the bells were wired in series. While dialling, one of the dial contacts stopped you hearing clicks in your ear, another was used to prevent the bells on other phones tinkling. Dialling was 1-10 impulses (circuit breaks) at 10 per second, followed by a pause (300ms?) The phone internally had a number of tags that were connected to the circuit, various switched and the handset. They could be set in different configurations for different uses. It should be possible to just rewire it so that 2 wires in the line cord connect to the handset receiver and another 2 connect via the Switch Hook and dial contacts. There are circuit diagrams on-line.
I bought all the bits for this rotary phone project, but didn't get to make it yet. blog.adafruit.com/2016/07/04/hack-a-rotary-phone-to-make-and-recieve-calls-arduinomonday/ There are some similarities - detecting dialled digits. I did get around to making a project using RFID cards, which used the SPI interface. This was a door access control system. These used a normally on electromagnet on the door. I used the opto-isolater and relay module circuit, but found the normally closed relay contacts failed open circuit after a few months. Went solid state and used a darlington transistor to directly drive the magnets. Single 12volt K80 supply (the built in relays failed) and a 7805 voltage regulator for the Arduino. I like the escape room ideas, so may adapt them for use at a fete for fundraising. (I used to have a fake safe - turn a dial, try the handle, if it opens win chocolate or set off an alarm).
Thanks for making this video. I'm designing a project which needs just what you've done; a phone that plays back messages when you dial different numbers. Thank you
Well done you should never take apart an old telephone we had one when I was young it's like people converting old oil lamps to electric just wrong anyway loved the video, your very clever loved the Maglock part that dropped on the floor
I believe that the final wire I didn't use (the blue one) is the "bell" wire, used for activating the ringer. However, certainly here in the UK, that requires a 50-60VAC current to activate, so I decided not to use it for this project. It wouldn't be too hard to place a small motor inside the phone that rang the bells on a lower DC current though!
Thank you so much. I used and Heraldo Telephone from Telefonica España. The speaker didn't work and I didn't have time to solve it, because I had to open my Escape Room, but the dialer opens the door perfectly.
Got the music playing now from the SD card. Probably worth pointing out that level shifting may be required to get the Arduino to talk to the SD card. Also the music must be mono 8-bit .WAV files , sampled at 32KHz or slower. And wav file names should not have more than 8 characters!
Is there a way for it to detect when the code is inputted wrong and make it say a warning message on the phone?? Maybe even after 3 times it shuts the power off, until manually restarted?
I've been working on this for a while. Everytime i dial a number it just repeats "Receiver Lifted, Receiver Replaced" over and over for the amount of pulses. Any idea what I'm doing wrong?
Hi, great video. I am beginner and hoping you use this as part of a party I am doing. What did you use to splice the phone cable? The phone cable is so thin, I tried using some B connectors to connect the green and red cables to my jumper leads but it doesn’t seem to register :(
Just created my first home Escape Room using ideas from your sequence lock - Thank you! Your videos have been extremely educational. On this rotary phone project, would it be easy to have a dial tone sound play when the receiver is first picked up that turns off when dialling a number?
Is there anyway to be able to do different length of digits? In the code its defined by "const int numDigitsInPhoneNumber = 5;" What would be the best way to have it be able to dial different length numbers eg; 999, 12345, 12345312 TIA
The phone does not need any power - if you mean the thing slightly down and right from the Arduino, that's just a line of terminal blocks to allow the cables to be easily plugged into the breadboard, e.g.: c1.staticflickr.com/9/8723/29338211736_27581c12ca_o.jpg
Did you use an original unconverted 746 for this project? If so do you think one of the new 746 phones that is designed to work on the modern phone network would also be compatible with your project? If fear not since I believe that it is only two wires now rather than four.
I'm using a completely unconverted 746 which I bought off eBay that had come from someone's aunt's loft I think, where it had lay for many years! I'm not familiar with "new" 746 phones, but if they use tone dialling I'd use a different approach instead - using a PAPT and a private PBX server running on a Raspberry Pi, say - to intercept and act on the DTMF tones instead of listening to rotary pulses.
@@PlayfulTechnology That increases the cost considerably though... Do all BT phones come with the BT Connector, or are the later ones RJ-11? ( (I left the UK a long time ago!)
@@duncanx99 UK phones use 431A connectors, not RJ11. As for cost for my other solution, a Raspberry Pi is around £30, and a PAP2T is around £20. More expensive than this approach, yes, but also more powerful and feature-rich (and doesn't require any hardware modification)
I started a new tutorial series explaining this approach - first two videos are now online here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-kbODHbJyEX4.html
I think the general term for it would be "electric cabinet lock". If you search for "12v cabinet Lock" on Amazon you should see some similar ones for sale (at least if you live in the USA)
Hi there, struggle to get mine to work at the moment. When the handset is lifted the serial monitor doesnt have it registering as lifted and then when the i pull one of the numbers around it then displays reciever lifted and when the dial spins back it displays reciever replaced. It only does this when the actual handset is off the hook. Any thoughts on what is being messed up here? Thanks
Yeah and that partly solves the issue of registering the phone off the hook but then every time you dial a number it just flickers the reciver lifted/returned without counting dial numbers. On startup i get this on the serial montor Serial connection started Setup Complete (handset lifted at this point) Receiver Lifted Receiver Replaced Receiver Lifted Receiver Replaced Receiver Lifted (handset now in the air. pull number 1 around and let go) Receiver Replaced Receiver Lifted Receiver Replaced Receiver Lifted Receiver Replaced Receiver Lifted
Really clever how you insulate the circuits, But in my opinion you use to much single parts. There is a option to use a single device which does all the operations on it's own. Check on RU-vid DigitalTechUSA or The Lockey escape rooms in UK
Yes, you can. Personally, I find that including debounce procedures in the code makes the problem (and the solution!) more explicit and easier to understand, but you can certainly do it using a purely hardware solution instead if you prefer.
