Arduino-Controlled Rotary Telephone (DIY Escape Room Prop Tutorial)
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- Опубликовано: 3 июл 2024
- In this video, I'm going to revisit and redesign an idea from a tutorial I made a few years back - the rotary phone escape room prop. I didn't realise it then, but my last project ended up being quite specific to handsets on the UK telephone network (with assumptions about particular timing patterns, wiring etc.), and so ended up being not as portable as I hoped - apologies to anyone who had difficulties following along from other countries!
So, for this project, I'm taking a completely different approach - wiring an Arduino (or ESP8266 / ESP32 or any similar microprocessor) directly to the mechanical components of an original 1970s phone - the rotary dial, the hook switch, the solenoid that rings the bells, and the microphone and earpiece speaker. This should be completely portable between handsets, whatever public telephone network they were designed to be used on.
Then, using a DFPlayer Mini MP3 module to handle the audio output, I'll show you how to program completely custom behaviour of the telephone as a Finite State Machine (FSM): you can trigger incoming calls (manually, via a switch in the control room or from control software such as Node-RED/M3/ERM) that makes the telephone ring and, when answered, delivers a specific message to players. Or you could have players dial an outgoing call to any one of thousands of different numbers, of any length, each one mapped to a unique MP3/WAV audio file on the SD card inserted into the DFPlayer. And, you can have the behaviour of those numbers change dynamically during play - to play different messages, or for certain numbers to be engaged or unobtainable at different points in the game, for example. This provides many different opportunities to integrate into an escape room game prop.
Since the entire behaviour is running on an Arduino, it's also easy to program in the ability to control any other external hardware - to release a maglock or power any other device via a relay etc. I believe this makes this the most flexible and feature-rich rotary telephone prop tutorial available.
Timings
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00:00-00:45 Introduction
00:44-03:35 Demonstration of incoming and outgoing calls
03:36-06:56 Hardware design decisions
06:57-15:27 Identifying components of the telephone handset
15:28-26:11 Wiring the telephone hardware to the Arduino
26:12-29:28 Using a Finite State Machine (FSM) to model telephone behaviour
29:29-01:06:01 Arduino (ESP8266/ESP32) code listing
01:06:02-01:07:07 Wrapup
Resources Used
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Rotary Pulse Dial telephone, ~$10 www.ebay.co.uk/sch/i.html?_fr...
DFPlayer Mini MP3 Module, ~$3 www.banggood.com/custlink/Kv3...
Mini Motor Shield, ~$3 www.banggood.com/custlink/v3K...
Arduino Nano, ~$2 www.banggood.com/custlink/mGG...
Code & Wiring Downloads
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If you'd like to support me making more video tutorials explaining how to use tech in escape rooms and other playful settings, please check out my Patreon at / playfultech , where you can also find code downloads, wiring diagrams, and additional resources for this and all my other tech projects. 
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Including the inner working knowledge is awesome. Highly enjoyed this.
I've been looking to dozens of these types of projects, this is by far the best documented and explained one I've found. Thanks!
Loved the deep-dive, thank you.
What a fantastic modular piece to add to a larger puzzle! Beautiful and very informative as always. Thank you…going to try locating a dial phone later today….
I'm working with a friend on an interactive art project where we would like to use a POTS rotary dial phone. This comprehensive breakdown of your solutions was hugely helpful and should make completing and expanding our plans much easier! Thanks!
Amazing walk-through. Thank you so much!
This is genius. Thanks for your videos. Hope you are doing well during this crisis.
Thanks so much for the line by line details of the code. Your voice reminds me of "The Secret Life of Machines". Well done. I like how you contain the name of the sketch in the sketch. I had been typing it in manually but this is so much better. Really helps when you need the name of the source file when you want to edit the program.
Great video! I found one of those old phone at the dump and I brought it home. Unfortunately I was most interested only in the dialing mechanism and the ring bell, now that I have seen this video I realized I could have built a prop like thet for myself if only I hadn't trown away the rest. If I'll ever find another I'll keep everything. Thanks for sharing!
As you said - add Node-Red into the mix and you could get the phone to ring when someone opens a drawer, or dial a number to unlock a door elsewhere in the room. Great project!
I love Node-RED! So easy to integrate, well, almost anything.
You are a genius!!!
Just acquired a rotary phone but found the internals totally different. The hook switch, for example, has seven wires (ormally open pair, normally closed pair, and a SPDT set of three) and the ringer coil uses four. Working through making good use of the details from the video. Everyone needs a good challenge once in a while.
One addition I hope to add is for a scenario with a message like "Don't talk. They are listening. Tap twice if you understand." and turn the receiver into a variation of a knock puzzle. I mean, it's there, and shouldn't be difficult to merge into code on a Nano. Thanks much for the inspiration.
One thing I've discovered after making a couple of phone-based videos now is that there is a huge variety in telephone hardware used across the world (and in handsets from different eras!). So any guide that describes a certain number of wires, of a certain colour, is very unlikely to be universally-applicable!
Anyway, glad you managed to do the investigation and got it working for you - great job :)
If people do want to use the microphone they need to be aware that it's a carbon granule microphone that changes resistance rather than a standard microphone that generates a small voltage, reason being that tiny voltage would never survive transmission over long distances without amplification and a balanced transmission system whereas a variable resistance microphone basically uses current loop technology so you'd need to make the mic part of a potential divider.
This was very useful, thank you! I can now proceed with my project
Only real fans understand the reference at 59:47 😎
Thanks for the vid man!
cool Tele746, fitted loads of them in the past, normally 2 wire line is used and a cap is put acroos the line for the bell circuit, usually 48volt dc on uk phones, spent many aday running in cables and testing them on your tongue, alright till some one rung the line the approx 18 hz ringing across our tongue.
the dialing is called loop disconnect.
awesome!!
For true realism you need to include howler tone so if the handset isn't replaced properly then after a while a loud tone is played that can be heard even if you're just close to the phone to alert your attention to it.
Besides the custom functions you could add the ability to dial 9 to make it work as an actual phone.
Built one just like this a few years ago
Great project! Thanks for sharing. Any idea of why sometimes you hear a long beep instead of the greeting message? Mine does this about 30% of the time.
Hi Alastair, I love your videos so much. You explain everything very clearly. I've also seen the old one with the rotary phone. Is it possible to do the same things with a tone phone? Can you please make a video about that or give a short explanaition.
I have also a second question: what kind of power supply do you use or recommend for powering an Arduino, LED stripes, 12 V locks and these things?
I would be glad, if you can help me with these two questions.
Thx and go on with your videos.
use a tone decoder chip.
Any chance of making this code suitable for a 4x4 matrix keypad phone?
Hello, thank you for your page! I'm just starting out and am excited to get through some projects. However I'm not getting the difference in resistance over T5 and the T19, for the hook switch - it stays on value 1 do you reckon this is a faulty switch ? I have the same model as shown. I do get a change in resistance on T2. 13:37
One issue I have is that it will only "pick-up" during the ringer break. If the ring is sounding and you pick up, it will just keep ringing. Any ideas?
Can you imagine making an escape room with people that have no idea how to dial a rotary phone? That would be hilarious!
they must be pretty stupid
I love this... phone hacks are cool enough, but when it's a GPO 700 series too? ... sigh!
In mine, I just built my ATTiny board into the shape of the circuit board already in the GPO-746 and connected to the solenoids and dial from there. But I ended up needing to put a new microswitch for the "hook" because the existing one was on the GPO board. And I powered the bells from ATTiny controlled DC with an individual connection to each solenoid... which meant 20V DC not 40V AC.
Can you make it so that when it’s picked up a message plays and then people can record their own messages which are kept
Where can I buy a premade one? Having trouble finding one, thanks.
Nice project! Is it possible to make a call back or ring without dedicated swithc/button? (for example phone calls by it self after 3-10min, or you dial number and it calls back after some x min.) Thanks!
Excellent video, thanks....awesome prop, enjoyed your video, very informative....got a western electric 554 a/b 72 rotary wall mount...will this work?
Please let me know if this worked for you! Having trouble finding an original gpo 746 and starting to wonder if a western electric would be easier to find without spending over $50
Hello Alastair, is it possible to operate the phone by remote control, particularly the ringer aspect? My project requires that the phone can ring a few times when not plugged in, then when eventually answered a voice/message could be heard. Thank you and thanks for this wonderful upload.
Hi Alistair, been watching this vid a few times and going to give it a go. It looks like the motor module is sold out. Others that mention L293D look bulkier and more complex - would they work anyway or could you post a link to an alternative one? :-)
Hi Alister, I subscribed on the Patrion and set up the phone like yours. The only problem I'm having is the ringer was burned out on my phone so I'm using a motor to spin a small weight to ring a bell. I don't understand how to change your loop codes to just activate a relay on 3 seconds off 2 then repeat untill picked up. Any advice?
What does the F() function do?
Also 12v moves the clapper ever so slightly on my phone, do I need more voltage or are there some component in my phone that interfere?
i have the same question about the 12v DC input. i tried with 9V and the bell doesnt ring at all but i can hear a clicking noise. Then i tried 12V and the bell rings but misses some rings. Wondering do i need a higher voltage DC input? Or can it be the Ampere of the input that are responsible? Any advice would be greatly appreciated!
Do you ever sell any already made?
Do I understand it right, that you will not include the arduino stuff inside of the telephone? So if it is external, do you re-use the old 4 pole telephone cable? So there will be 7 pins from the telephone to the cirquit: hookPin, dialPin, numberPin, 2 ringingPins, speakerPin and Ground. So 4 pole cable isn't possible, is it? I understood at the beginning of the video, that it will not be nessesary to open the original telephone housing?!
Will these accessories be found in eBay in the states and work in similar fashion
Public telephone networks differ from country to country, from the voltage on the line when the phone is on-hook, the frequency of the AC ringer signal, and the way pulses and voice data is encoded.
BUT, for this project I'm just using the basic components found in the telephone- the microphone, speaker, mechanical dial mechanism etc., and they work the same wherever.
Hi Alastair, I've bought all the bits and pieces for this project. I'd like to buy the code and went to the Patreon page. I haven't used it before. I can't figure out what I'm signing up to though as it mentions a monthly bill based on a 'pledge, monthly max and number of paid posts'. How do I buy the Arduino code for this? Many thanks.
basically, you just sign up for a subscription on his Patreon on a tier that allows code to be downloaded, but you cancel before the first month is over to give the creator some money but not be stuck with a subscription when you just wanted a one off payment
Can you make this into an audio guest book. How can we record "voicemails"
Coming up!
@@PlayfulTechnology omg yesss! Also I joined your patreon!
Hey, love the videos. I have a question about a project. I have an idea for her. I'm trying to program a phone so that a particular number will play a particular saved audio file. Like dialing one will play a particular file, dialing 32 will play a particular file. I didn't know if you had something in mind that could help. I have all the equipment for the audio guess book. Thanks in advance.
Hi Randolph, yes I've done that in several projects on this channel - using an Arduino, a Raspberry Pi, or a Teensy. It's just detecting input (via a rotary dial, as on this project), and triggering appropriate output (I.e. playing sound file from SD card, via speakers)
@@PlayfulTechnology Thanks, I'll look through your old videos to see if I can find a project that breaks it down. Butttt I may be back to see if you would be kind enough to write a script for me (of course with a donation :)
Is L298N Dual H-Bridge Motor Driver a good alternative for the mini motor shield?
Hi! Did it work with the L298N? I have the same question
yes
@@rabbit74701, yes it did :)
Hi, i don't understand something.
How Can you connect Arduino cables with phone connections ?
You mean physically make the connections? Most old handsets like this have screw terminal blocks inside them, so that's trivial to connect. Otherwise Wago connectors are very useful to join bare wire ends together.
@@PlayfulTechnology Yep i've tried to connect screw blocks with Arduino jumpers but it wasn't a success
Is there anyway you can record people talking into the telephone say to leave messages?
Yes, definitely - there's a few Arduino shields that have built in microphones and recording capabilities - I might look in to using one of those in a future video - cheers!
@@PlayfulTechnology Please!!!!! I've been trying to figure out how to do this for ages. We need your help!
@@PlayfulTechnology Hi there! I'm also interested in repurposing my phone so that I can record people leaving messages! Just like an Audio Guest Book at weddings! Any help would be much appreciated !
Hey were you able to figure it out!? I'm looking for the same thing. Interested in building my open audio guest book
@@johannasr8645 Hey Johanna were you able to figure this out? I've also been trying to create my own audio guest book!
it is possible to get a finished product?
Hello! I just discovered your channel and subscribed! I have a request. How can I make my own audio guestbook with a rotary phone. For example companies like FeteFone, After the Tone and Life on Record offer that service. But I don't want to spend 300+ for one time use.
Thank you!
Hi! It's funny - I've actually had several people ask if I could do a tutorial on making an "audio guestbook", and I have to confess I'd never even heard of them before! So, can you explain how you'd expect it to operate in a bit more detail? Do you have to press any buttons or dial any number at all? Or do you just lift the handset and speak ("after the tone"?) and it records everything until you hang up?
@@PlayfulTechnology Wow! First of all, thank you so much for taking the time to read my comment and write back!
The audio guestbook is a new fad that started probably a few years ago.
To answer your question, based on some of my research it looks like you can either have the guest dial 0 and they'll hear the greeting first then after the tone it records. Or a common one is as soon as you pick up the phone you'll hear the greeting and then recording starts after the tone. Each recording ends as soon as you hang up. So it can be simple as just picking up the phone or dialing 0.
Ok, cheers - that doesn't sound too hard. I'll look into demonstrating that in a future tutorial.
@@PlayfulTechnology I'd also be very interested in this tutorial. It would be awesome!
@@PlayfulTechnology awesome thank you so much!
Is that an original phone or a replica?
That's an original.
Your bell ringer could have been done with a 555.
Your better using MODULO to get 0 for 10, so pulses = pulses % 10 (in javascript) will get you 0 if its a 10 but not affect other numbers.
Yes, it could.
there is no positive and negative on telephones of that age they ran on 25 Hz AC
www.britishtelephones.com/howtele.htm#:~:text=In%20the%20United%20States%2C%20the,also%20the%20power%20supply%20line.
he is simulating ac from dc supply, like making a dc motor run forward or reverse.
@@TheUnofficialMakerAn H-Bridge essentially.