An old rotary phone can be used for a number of purposes in your Arduino projects - use it as a novel input device, or use the Arduino to interface a rotary phone to your computer.

This is a very basic guide describing how to interface the dial to an Arduino, and get the number dialed passed into a computer over the Arduino's serial link.

Step 1: Remove the dial from the phone

First step is to remove the dial unit from the phone. I'm using a GPO phone of some sort from the 1970s.

On this phone, the dial popped straight out - I just needed to give it a tug. If it doesn't, you may have to open up the phone and work out how to get it off.

There were five cables connected to the back of the dial unit. On my phone, these were regular spade connections, so I loosened the screws and pulled them out. If you want to re-assemble your phone, remember to record which color wire goes to which connection.
Do you have a sketch where this converts rotary pulses to DTMF tones? I want to use an old rotary phone generating DTMF for dialing.
<p>If you want to do it yourself using arduino hardware, I found a german website of someone who did it, including circuit descriptions and source code: <a href="https://www-user.tu-chemnitz.de/~heha/basteln/Haus/Telefon/Impulswahl%E2%86%92DTMF/" rel="nofollow">https://www-user.tu-chemnitz.de/~heha/basteln/Haus...</a><br>Be aware, that you should replace the arduino bootloader and program the chip directly to be able to dial right away. The microprocessor, being powered by the telephone line, will start running only after you pick up the phone. If you keep the original arduino bootloader in, it will wait to be programmed before starting to run your own code, and this takes some time.</p>
<p>Just as a side note, I picked up an old old rotary phone at a yard sale and it works great on FIOS! But this would help since no one believes you when you push 0 and need help because you can't touch tone their menus.</p>
<p>jayne15 - With a rotary to DTMF or Touch Tone converter if you need Operator / Attendant, you would dial 0 (zero) the circuit would convert the pulses to the appropriate tones and the system would then dial thru. The same goes for &quot;press 1 for... or Press 2 for... &quot; the converter circuit counts the pulses and the generates the tone desired. Here is a link to a device that does just that, this is it costs about $45. You install it under the base cover of the phone Hope this helps. </p><p><a href="http://www.oldphoneworks.com/rotatone-pulse-to-tone-converter.html" rel="nofollow">http://www.oldphoneworks.com/rotatone-pulse-to-tone-converter.html</a></p>
<p>Hey @<a href="https://www.instructables.com/member/JMorton3" rel="nofollow">JMorton3</a> any chance you managed to do this? I'm looking to do something fairly similar for presenting a number of tracks in an exhibition.</p><p>I actually wanted the phone to ring and then play a track when the receiver is lifted. but that might be too complex...</p>
<p>Hey @<a href="https://www.instructables.com/member/JMorton3" rel="nofollow">JMorton3</a> any chance you managed to do this? I'm looking to do something fairly similar for presenting a number of tracks in an exhibition.</p><p>I actually wanted the phone to ring and then play a track when the receiver is lifted. but that might be too complex...</p>
<p>worked for me. thank you.</p><p>just change the pinMode to INPUT_PULLUP</p>
<p>How to store that data as 9 digit string and compare it with a specific one?</p>
<p>Love the write-up! I have a question though - rather than sending the single numbers down the serial line to the computer, can they be stored in separate variables? Such as 1st number dialed is stored in numOne, second number dialed to be stored in numTwo, and so one, so that the Sketch can make use of them? I am planning on a rotary phone which, when dialed any two-digit number, will play a corresponding MP3 file back through the earpiece. Thanks in advance for any help on this!</p>
<p>Hey thanks for the help!! set up my rotary phone to transmit a signal to turn on and off outlets around the room.</p>
<p>Could you please share your arduino code?</p>
i have a question <br>and i do need an awsner soon <br>how do you add the numbers to a giant string <br> <br>i mean you dail 1 then 9 then 8 <br>and get a variable of 198
<p>Serial.println(count % 10, DEC);</p><p>if using println, the output will jump to a new line after printing.</p><p>Try to use print without line changing. </p>
<p>Made it and it works like a charm, even without any adjusting.</p><p>Thanks for the pointers!</p>
<p>Good Afternoon, please, you could tell as it did for the numbers appearing on your monitor ?? because I'm trying to do this and I can not. <br>I await return <br>py5kyw@yahoo.com.br</p>
<p>i did it :) and it works :)</p>
I just bought an old antique phone. Would love to have three options: (1) mod internals with modern phone to make calls through landline connection, (2) have mod to connect to iPhone/Android/Blackberry phone to make calls but through phone, and (3) set it up as a Skype or Google hangout steampunk styled device attached to a display/monitor with Webcam. I figure That I can come up with a 3-option switch that could allow me to select between the 3 options. Any thoughts on how to do parts (2) and (3) successfully?
add it to a gsm shield and make a phone out of it
Changes to the code to cover different rotary dials.<br> <br> Serial.print(count - 1);&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // Rotary dials that begins with zero and ends with 9<br> Serial.print(&quot;&nbsp; &quot;)<br> Serial.println(count % 10, DEC); // Rotary dials that begins with 1 and ends with zero
Hello, I just tried the code and it works. :) <br>My problem is this: <br>I'd like to enter a code via the telephone dial to open a door. If the code is correct then the door should open. <br>Can you help me?? <br> <br>Greetings from Germany Maik
This setup and program works perfectly on the old Dutch PPT T65 rotary telephone, just hooked it up. Now to figure out how to play sound so when the right number is dialled, one will get a certain message (that's for a different hobby of mine, geocaching) <br /> <br />Thanks a bunch for these instructions, a great help!
Why is it necessary to disassemble the dial? Couldn't you read the pulses directly from the phone line (red and green wires). All it is is a sequence of open-close pulses from the mechanical dial.<br>
had a problem with getting teh wrong output to the numbers (1 became 2 and so on) solved it by changeing the debounce to 20mille seconds and this did the trick
same setup here... makes for much easier programming ;)
I like the Skype idea. One could install the necessary computer inside of an ornate base with a flat screen monitor mounted behind the phone and what ever other antique details. It could be a very Steampunk video phone or perhaps use aluminum and go with a Machine Age phone. Oh for the time to explore all the options.
Idea: <br>-use as a dieselpunk safe/door lock.<br>-Interface dialer, handset, and google voice to receive and make calls from a physical phone.
hello i am interested in electronics for my end of year project, but i am just starting out properly into electronics and programing and saw the arduino as a good starting point. could you recomend any reading material i could look into (already have the Arduino Notebook from their website and the make Magazine getting started with Arduino)
&nbsp;On the dial I've pulled out to use there's another switch that opens when the dial is turned to a number and closes when it has finished pulsing. I'm planning on using that instead of waiting longer because I'm also going to be having a keypad matrix to scan and an LCD to power!
splendid, splendid. Haven't thought about pulse dialling since I stopped working for a telecomms equipment company, lo, these many moos ago.<br /> <br /> I&nbsp;had fun explaining to my four year old about how this phone works a bit differently from all the phones he sees in the house.<br />
lol @ &quot;many moos ago.&quot;<br /> <br /> I too measure my time scale by bovine vocalization! haha<br />
Hang on a bit, you said that if you dial 9 that it will tap out nine times on the switch. As I&nbsp;recall, when hand keying a phone, you add 1 to every number.<br />
Hi,<br /> <br /> Thanks for the comment - an interesting topic. It appears that the pulse dialing regime varies by geographic area, however in the UK (where this telephone is from) and North America, the number of pulses corresponds directly to the number dialed. This is certainly what happens for my telephone - obviously people in other countries may have to alter the source code to account for their particular phone.<br /> <br /> Cheers :)<br /> <br /> From <a href="http://en.wikipedia.org/wiki/Pulse_dialing">en.wikipedia.org/wiki/Pulse_dialing</a> :<br /> In most countries one click is used for the digit 1, two clicks for 2, and so on, with ten clicks for the digit 0; this makes the code <a href="http://en.wikipedia.org/wiki/Unary_numeral_system" title="Unary numeral system">unary</a>, excepting the digit 0. Two exceptions to this are New Zealand, with ten clicks for 0, nine clicks for 1, and so on, and Sweden, with one click for 0, two clicks for 1, and so on.<br />
One word: Skype! ;)
It's a plan - that'd be pretty cool!

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