With the gravitas of [Michael Douglas] in Wall Street and the technological amazement of [Zach Morris] on Saved By The Bell, the classic 1980s ‘brick’ cell phone has a lot to offer these days. Not only is it large enough to be used as a blunt weapon, it’s also useful as an anchor and more durable than an old-school Nokia. Most, if not all of these phones have gone silent since analog cellular service went dead a few years ago, but that didn’t stop [Andrew] from bringing his back to life.
The core of this build is a 128×64 OLED screen that replaced the old seven-digit, seven-segment display and a very small GSM module. The ancient PCB was discarded and a new hardware revision was created in Eagle based on an Arduino-powered microcontroller. The buttons from the original phone remained, thanks to a custom designed resistive button footprint on the PCB and a bit of conductive ink.
What’s surprising is this phone actually works. [Andrew] can not only receive texts on his phone, but also send them using his own implementation of a number pad keyboard. It’s an awesome build, and from what we can tell, the first proper DIY cell phone we’ve ever seen. About time someone got around to that, and we couldn’t have hoped for a better form factor.
[John Thomson] usually keeps his phone on vibrate when it’s in his pocket, and he often forgets to turn the ringer back on when setting it down to charge. This typically results in a bunch of missed calls in the meantime, so he had to devise a way to counteract his forgetfulness.
You might remember [John] from the Santa-pede contest we held last December. He wanted to try his hand at yet another competition, the Avnet Dog Days of Summer contest, so he scrambled to come up with a quick fix for his situation. He concocted a simple circuit based on [ChaN’s] design for a “Simple SD Audio Player with an 8-pin IC” that would alert him to incoming calls, even when his phone was on vibrate.
[John] used an ATtiny85, just as [ChaN] did, adding a speaker for sound output and a piezo sensor to detect his phone’s vibrations. When the piezo senses a bit of motion, the audio player kicks in, blaring a series of sounds that are sure to get [John’s] attention.
While he was organizing a party, [Mike Seese] hit upon the idea of chatroom that would operate over SMS. Not being content with the ‘reply all’ function, [Mike] built a Group Messaging Service that runs on his home server.
The chat room is initiated by sending a text to a server. Your friends then reply, and the chatroom is then opened. The project was written in C++, and [Mike] put everything on github for your perusal. The software does use libraries from /n software’s IP*Works, but if you have any trouble obtaining those libraries feel free to drop [Mike] a line.
The great thing about this project is the fact that it’s platform independent – as long as a phone can do SMS, it’ll work. Seems like a great thing for those of us still using the old Nokia ‘bar’ phones. An SMS chatroom has been done before but this is the first time we’ve seen a build that will run off your server, and not internet-based services.
While it may not be the best idea for people without unlimited texts on their phone plan, it’s a really great idea and we’re wondering why something like this isn’t available via Google Voice.
Hackaday forum member [Dan Fruzzetti] wrote in to share a simple, yet useful hack he built just the other day. He and his wife both have Evo 4G smartphones and they were pretty disappointed in the lack of portable charging solutions available.
Instead of buying something and modifying it to his needs, [Dan] decided to build a quick and dirty charger instead. His ghetto-mintyboost was built into a cheap project box he found at Radio Shack, which is stocked with a set of four D-cell batteries. The batteries were wired in series and connected to a pair of salvaged USB ports mounted on a small piece of protoboard.
Knowing that most portable devices get 5.7v from their chargers already, he was not worried about hooking his phones straight into the 6v battery pack he built. He says that the phones actually charge pretty quickly, and that he estimates he should be able to get about 50 charges out of the box before he needs to swap the batteries.
This is not a complex hack by any means. It is quick & dirty, solves an annoying problem, and it’s dead simple to build. That’s exactly why we like it.
That title’s not really fair to [Evan], but he did write a cellphone tetris game that causes your handset to automatically telephone him if you win. He’s using two applications that we’re not very familiar with, Twilio and Tornado. The former handles control input from the cellphone via their simple API. The latter is a web server and web framework that runs the actual game.
If you’re interested in how he put the two together you can poke around in the code. If you really don’t care about how it is done, you might just want to win the game, automatically giving [Evan] a call, running up his wireless bill in the process.
Help us add some value to this article by leaving a comment. We’d like to know how Twilio compares to Google Voice which doesn’t seem to have a published API (but there is some work in that area). We also think web-based cell phone interactivity, already popular in hacks, is just beginning to build some steam. What are the tools you use to make cellphone interfaces easier and quicker to implement?
Hackaday alum [Will O'Brien] has been doing some cellphone integration work. He recently picked up some Motorola c168i cellphones from eBay. It turns out there is a serial port that uses TTL communication with a standard head-phone jack as an interface. [Will] soldered up a connector and used a USB to FTDI cable to interface with the phone. To his surprise he was able to read off the stored text messages even though they were PIN protected in the phone’s operating system. The messages on these units were trivial but this is another example of the importance of clearing your data before discarding your devices.
[Karsten Nohl], with a group of security researchers has broken the A5/1 Stream Cipher behind GSM. Their project web site discusses their work and provides slides(pdf) presented at 26C3. A5/1 has had known vulnerabilities for some time now and is scheduled to be phased out for the newer KASUMI or A5/3 block cipher. This should be an interesting time in the cell phone business.
Thanks to [Tyco] and [MashupMark] for pointing us to this story.