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.
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.
What’s it made with?
- Raspberry Pi 3 Model B
- USB speaker
- Waveshare UPS (Uninterruptible Power Source)
- Waveshare GSM HAT
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.
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.
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.