Perhaps it's gathering dust in a closet after your landline was disconnected, or it's an “inheritance” you've decided to keep, waiting for the right hack. Well, how does this sound? Making the rotary phone connect to the cellular network. In essence, you'd transform it into a “mobile” phone with the help of an Arduino Uno (or similar, based on the ATmega328), and a compatible GSM module...
Tired of glass rectangles? Fed up with apps and notifications? If you answered yes to both, honestly I can't blame you. The market keeps repeating models and asking exorbitant prices for them, but DIY gives us an escape. A couple of days ago we explored the possibility of transforming a damaged smartphone into a laptop, something different and definitely useful for extracting life from a device destined for e-waste. However, nothing stops us from going a bit deeper...
For example, in mid-February we learned about a mobile phone designed by engineer Justine Haupt, with a very special feature: a rotary dial. In short, what Justine was looking for was the convenience of a mobile phone without its traditional distractions or weaknesses. But there's also another possibility: instead of bringing the dial to the mobile, place the “mobile” inside a rotary phone. How does that work exactly? Here's a video:
The user “Proton Gamer” explains in his guide how to make the rotary phone's solenoid work (in theory it needs more than 50V, but with 8.4V it should be enough to get a good “ring”), and how to connect the components for the first tests. Then he focuses on the speaker and microphone connections, and on the rotary dial (by the way, did you know you can use it to adjust the volume in Windows?).
In total, the required materials (besides the phone) are four: an Arduino Uno or ATmega328-compatible, a DRV8833 module (breakout recommended), a power supply (between 7.4 and 10.8 volts), and a SIM900 module with a small modification. The price of the SIM900 is quite reasonable (around 8 or 9 dollars on AliExpress/eBay), but you must verify that it's compatible with your region. The SIM900 doesn't go beyond 2G, and many countries have already retired those networks, although in Spain and Latin America they're still active. The weekend is approaching, why not give it a try?
Access the project: Click here
