Restoring a 19th-century telephone with Raspberry Pi

When Mark Lister stumbled across this antique telephone at an auction, he had much more in mind for it than a simple display piece to adorn his already bulging shelf of oddities and knick-knacks. (Disclaimer: I have no evidence that Mark’s home decor isn’t completely minimalist and knick-knack free; I’m just projecting.) He threw a Raspberry Pi inside it, did away with the external cables, and turned it into a modern mobile phone.

mark lister antique phone retrofit
Magnificent beast

Of course, it’s only “mobile” if you’re OK with lugging around an antique hunk of metal the weight of a small baby. But semantically, technically, it’s a mobile device.

The maker’s Hackster bio says that, while he started coding in 1980, he has only just got into Raspberry Pi. And this retrofitted beauty looks like his very first Pi-powered project. Not bad at all for a newbie.

mark lister antique phone retrofit
Images from Mark’s Hackster post

What’s it made with?

The GSM HAT is specially made to allow Raspberry Pi to make telephone calls, send messages, and connect to the internet.

How does it work?

The rotary dial performs its original function, and the original wires are now connected directly to the Raspberry Pi GPIO. Mark is a genius and wrote code that converts the pulses made by turning the dial into digits that the phone SIM card mounted on the GSM HAT can recognise.

antique telephone operating system map
Mark created this simple diagram to show you how everything is connected

As if this weren’t enough cleverness for one project, Mark also added speed-dial functionality and caller ID. If the code recognises a telephone number it has dialled before, it speaks the person’s name through the speaker while the phone is ringing.

And because the UPS only lasts 20 minutes, there’s a port at the back so you can connect to a USB battery and make longer calls.

Retro ringtone

Mark understands that most of the reason people have retro phones is because they like the old‑fashioned brrrrring brrrrring ringtone. So he installed a speaker to play an MP3 sound of an old telephone ringing when someone calls the device. That’s it. That’s the speaker’s entire job. Worth it. Definitely our MVP of the entire hardware list.


John avatar

I wonder if you can type messages in the olde fashioned way. 1=a, 11=b, 111=c, 2=d, etc. Not sure if I can still type like that, but I used to be able to bash out SMSs quite quickly.

Ashley Whittaker avatar

Mark, you should def retrofit a massive 1980s in-car phone next.

Paul Roney avatar

I think this is a 20th century phone and not a 19th century phone. The first phone with a rotary dial was introduced in 1904, and use did not become widespread until after the First World War. Nice project though!

Michael Holding avatar

I’ve got a fairly ancient French phone I’ve been meaning to do something with, are there any project details available ?

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