Turning an old diavox phone into a cellphone. No smart stuff, just a telephone. Pick up the handset and dial just like the old days.

I remember the days when a phone was just a phone. Pick up the handset dial the number, just you the phone and the other person you are talking to. Place the handset back on and the call ends. No fancy smart features to distract you. This project is about turning an old telephone into a portable cellphone and learning new things on the way.

[Evan] couldn’t find a phone he liked, so he decided to build his own. There are advantages and disadvantages, as you might expect. On the plus side, you have the ultimate control. On the negative side, it doesn’t quite have the curb appeal — at least to the average user — of a sleek new cell phone from a major manufacturer.

The phone uses a Raspberry Pi, along with a 4G modem and a 480×800 touchscreen. There’s a laser cut box that measures 90x160x30 mm. For reference, a Google Pixel 7 is about 73x156x9 mm, so a little easier on the pocket.

But not one the pocketbook. The OURPhone only costs about $200 USD to build. There are trade-offs. For example, the touchscreen is resistive, so you’ll want a stylus (there’s a slot for it in the case). On the other hand, if you don’t like something, it is all there for you to change.

https://github.com/evanman83/OURS-project/

While it might seem like mobile phones are special devices, both in their ease of use and in their ubiquity in the modern culture, they are essentially nothing more than small form-factor computers with an extra radio and a few specific pieces of software to run. In theory, as long as you can find that software (and you pay for a service plan of some sort) you can get any computer to work as a phone. So naturally, the Raspberry Pi was turned into one.

[asherdundas], the phone’s creator, actually found a prior build based around the Raspberry Pi before starting this one. The problem was that it was built nearly a decade ago, and hadn’t been updated since. This build brings some modernization to the antiquated Pi phone, and starts with a 3D printed case. It also houses a touchscreen and a GSM antenna to connect to the cell network. With some other odds and ends, like a speaker and microphone, plus a battery and the software to tie it all together, a modern functional Raspberry Pi phone was created, with some extra details available on the project page.

Raspberry Pi Phone
Raspberry Pi Phone-Your Own Phone That Can Call and Text Under $70
https://hackaday.io/project/187640-raspberry-pi-phone

Build Your Own Smartphone
https://www.instructables.com/Build-Your-Own-Smartphone/

Short preview of the Rotary Un-Smartphone

https://skysedge.com/

Many of us hackers have a longing for numpad-adorned mobile phones. We also have a shared understanding that, nowadays, such a phone has to be open and Linux-powered. Today’s project, Notkia, is the most promising and realistic effort at building a keypad phone that fits our requirements. Notkia is a replacement board for Nokia 168x series phones, equipped with an improved display, USB-C, Wi-Fi, Bluetooth, and LoRa — and [Reimu NotMoe] of [SudoMaker] tells us this project’s extensive story.

https://hackaday.io/project/185645-notkia/details

The smartphone represents one of the most significant shifts in our world. In less than thirteen years, we went from some people owning a dumb phone to the majority of the planet having a smartphone (~83.7% as of 2022, according to Statista). There are very few things that a larger percentage of people on this planet have. Not clean water, not housing, not even food.

How does a smartphone work? Most people have no idea; they are insanely complicated devices. However, you can break them down into eight submodules, each of which is merely complex. What makes them work is that each of these components can be made small, at massive economies of scale, and are tightly integrated, allowing easy assembly.

So without further ado, the fundamental eight building blocks of the modern cellphone are: the application processor, the baseband processor, a SIM card, the RF processor, sensors, a display, cameras & lenses, and power management. Let’s have a look at them all, and how they fit together.

My open source rotary cell phone went viral (surprisingly, to me and my husband), and people seem to be interested in it. The original description with links to notes and design files is here:
http://www.justine-haupt.com/rotarycellphone/index.html
and a starter kit is now available here: https://skysedge.us/​