1930s-Era ‘General Post Office’ Rotary Telephone Upgraded with FONA, #Arduino Mega, “Music Maker” Shield

This project by forums user jules999999 went through several designs before landing on the current build using Adafruit FONA, an Arduino Mega, and Music Maker shield, but the chassis has always remained the same: a 1930s-era type 332 GPO telephone. Read this forums thread to see how jules999999 arrived at some conclusions with this build.

Interestingly, on the project website the phone’s centrifugal brake is labeled as the ‘governor‘ – the same name of the braking system in some of Charles Adler’s same-era automotive inventions; I’m going to look up this device and patent and see what else I can find!




Yes, I’ve managed to get the dialler working with the FONA. The dialler basically consists of a pulse switch and a switch to indicate the end of a pulse train. Also there is a switch which opens when the handset is off the cradle. With these as Arduino inputs, it is relatively straightforward to count the pulses and add them to an array. I had to add a button to call the number when the dialling was completed. When this is pressed, the stored number is fed into the FONA library call routine. Pressing the cradle switch disconnects the call.
At this stage I have found that the speaker is much too loud to be held to the ear (even at volume’1′) so I need a series resistor. Conversely, the microphone does not seem sensitive enough so I have ordered an Adafruit amplified microphone. I am assuming that I will just connect the microphone ‘+’ on the FONA to the output of the amplifier via a capacitor (which way round, polarity-wise, needs to be determined) and use the ground as a common connection, leaving the microphone ‘–’ pin unconnected.
I am now on the next stage using an Arduino Mega with an Adafruit Music Maker. I have been trying to avoid devices such as LCD screens or LEDs to retain the vintage feel of the phone. Instead, I am hoping to use audio cues to indicate the status of the system, for example, a dialling tone to indicate whether the FONA is connected to a network when the handset is picked up off the cradle. The SD card can store pre-set numbers and audio cues. At the very least, I should be able to incorporate a dial operated MP3 player!
I am documenting this project at http://www.mr-r.co.uk/oldphone1.html if anyone is interested.

Read more here and here.

Featured Adafruit Products!


Arduino Mega 2560 R3: The Arduino Mega 2560 is a microcontroller board based on the ATmega2560 (datasheet). It has 54 digital input/output pins (of which 15 can be used as PWM outputs), 16 analog inputs, 4 UARTs (hardware serial ports), a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started. The Mega is compatible with most shields designed for the Arduino Duemilanove or Diecimila. Read more.


Adafruit “Music Maker” MP3 Shield for Arduino: Bend all audio files to your will with the Adafruit Music Maker shield for Arduino! This powerful shield features the VS1053, an encoding/decoding (codec) chip that can decode a wide variety of audio formats such as MP3, AAC, Ogg Vorbis, WMA, MIDI, FLAC, WAV (PCM and ADPCM). It can also be used to record audio in both PCM (WAV) and compressed Ogg Vorbis. You can do all sorts of stuff with the audio as well such as adjusting bass, treble, and volume digitally. Read more.

Adafruit publishes a wide range of writing and video content, including interviews and reporting on the maker market and the wider technology world. Our standards page is intended as a guide to best practices that Adafruit uses, as well as an outline of the ethical standards Adafruit aspires to. While Adafruit is not an independent journalistic institution, Adafruit strives to be a fair, informative, and positive voice within the community – check it out here: adafruit.com/editorialstandards

Join Adafruit on Mastodon

Adafruit is on Mastodon, join in! adafruit.com/mastodon

Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.

Have an amazing project to share? The Electronics Show and Tell is every Wednesday at 7pm ET! To join, head over to YouTube and check out the show’s live chat – we’ll post the link there.

Join us every Wednesday night at 8pm ET for Ask an Engineer!

Join over 36,000+ makers on Adafruit’s Discord channels and be part of the community! http://adafru.it/discord

CircuitPython – The easiest way to program microcontrollers – CircuitPython.org

Maker Business — “Packaging” chips in the US

Wearables — Enclosures help fight body humidity in costumes

Electronics — Transformers: More than meets the eye!

Python for Microcontrollers — Python on Microcontrollers Newsletter: Silicon Labs introduces CircuitPython support, and more! #CircuitPython #Python #micropython @ThePSF @Raspberry_Pi

Adafruit IoT Monthly — Guardian Robot, Weather-wise Umbrella Stand, and more!

Microsoft MakeCode — MakeCode Thank You!

EYE on NPI — Maxim’s Himalaya uSLIC Step-Down Power Module #EyeOnNPI @maximintegrated @digikey

New Products – Adafruit Industries – Makers, hackers, artists, designers and engineers! — #NewProds 7/19/23 Feat. Adafruit Matrix Portal S3 CircuitPython Powered Internet Display!

Get the only spam-free daily newsletter about wearables, running a "maker business", electronic tips and more! Subscribe at AdafruitDaily.com !

No Comments

No comments yet.

Sorry, the comment form is closed at this time.