The 2G Raspberry Pi Smartphone

April 4, 2015 by Brian Benchoff 32 Comments

For [Tyler]’s entry to the Hackaday Prize, he’s making something that just a few years ago would be unheard of in a homebrew build. He’s making a DIY smartphone. Yes, with cheap single-board Linux computers, GSM modules, and SPI touchscreen displays, it’s possible to build your own smartphone.

Inside [Tyler]’s DIY smartphone is a Raspberry Pi Model A, a 3.5 inch touchscreen PiTFT with 480×320 resolution, and an Adafruit FONA module The connections are simple enough; the TFT is connected over SPI, and the GSM module over serial. The entire device is powered by a 1200mAh LiIon battery, charged with a powerboost board, runs an operating system written in Python capable of making calls, sending texts, and takes pictures with a Pi camera.

This is not what you would normally call a smartphone. The FONA module is 2G only, meaning you’re limited to 2G speeds and 2G networks. AT&T will be shutting down 2G networks in a little bit, although T-Mobile will be keeping them up for anyone who still has an old Nokia Brick.

That said, [Tyler]’s phone is still exactly what you want in a minimal phone: it just makes calls and receives texts, it has a camera, and unlike the Nokia, you can take it apart and repair it easily. Not that you ever had to do that with a Nokia…

APRS Tracking System Flies Your Balloons

March 24, 2015 by Bryan Cockfield 27 Comments

Looking for a way to track your high-altitude balloons but don’t want to mess with sending data over a cellular network? [Zack Clobes] and the others at Project Traveler may have just the thing for you: a position-reporting board that uses the Automatic Packet Reporting System (APRS) network to report location data and easily fits on an Arduino in the form of a shield.

The project is based on an Atmel 328P and all it needs to report position data is a small antenna and a battery. For those unfamiliar with APRS, it uses amateur radio frequencies to send data packets instead of something like the GSM network. APRS is very robust, and devices that use it can send GPS information as well as text messages, emails, weather reports, radio telemetry data, and radio direction finding information in case GPS is not available.

If this location reporting ability isn’t enough for you, the project can function as a shield as well, which means that more data lines are available for other things like monitoring sensors and driving servos. All in a small, lightweight package that doesn’t rely on a cell network. All of the schematics and other information are available on the project site if you want to give this a shot, but if you DO need the cell network, this may be more your style. Be sure to check out the video after the break, too!

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Raspberry Pi GSM Hat

February 28, 2015 by Brian Benchoff 12 Comments

The Spark Electron was released a few days ago, giving anyone with the Arduino IDE the ability to send data out over a GSM network. Of course, the Electron is just a GSM module tied to a microcontroller, and you can do the same thing with a Pi, some components, and a bit of wire.

The build is fairly basic – just an Adafruit Fona, a 2000 mah LiPo battery, a charge controller, and a fancy Hackaday Perma-Proto Hat, although a piece of perf board would work just as well in the case of the perma-proto board. Connections were as simple as power, ground, TX and RX. With a few libraries, you can access a Pi over the Internet anywhere that has cell service, or send data from the Pi without a WiFi connection.

If you decide to replicate this project, be aware you have an option of soldering the Fona module right side up or upside down. The former gives you pretty blinking LEDs, while the latter allows you to access the SIM. Tough choices, indeed.

Over-engineering Ding Dong Ditch

December 11, 2014 by Brian Benchoff 20 Comments

One day, [Samy]’s best friend [Matt] mentioned he had a wireless doorbell. Astonishing. Even more amazing is the fact that anyone can buy a software defined radio for $20, a small radio module from eBay for $4, and a GSM breakout board for $40. Connect these pieces together, and you have a device that can ring [Matt]’s doorbell from anywhere on the planet. Yes, it’s the ultimate over-engineered ding dong ditch, and a great example of how far you can take practical jokes if you know which end of a soldering iron to pick up.

Simply knowing [Matt] has a wireless doorbell is not enough; [Samy] needed to know the frequency, the modulation scheme, and what the doorbell was sending. Some of this information can be found by looking up the FCC ID, but [Samy] found a better way. When [Matt] was out of his house, [Samy] simply rang the doorbell a bunch of times while looking at the waterfall plot with an RTL-SDR TV tuner. There are a few common frequencies tiny, cheap remote controls will commonly use – 315 MHz, 433 MHz, and 900 MHz. Eventually, [Samy] found the frequency the doorbell was transmitting at – 433.8 MHz.

After capturing the radio signal from the doorbell, [Samy] looked at the audio waveform in Audacity. It looked like this doorbell used On-Off Keying, or just turning the radio on for a binary ‘1’ and off for a binary ‘0’. In Audacity, everything the doorbell transmits becomes crystal clear, and with a $4 434 MHz transmitter from SparkFun, [Samy] can replicate the output of the doorbell.

For the rest of the build, [Samy] is using a mini GSM cellular breakout board from Adafruit. This module listens for any text message containing the word ‘doorbell’ and sends a signal to an Arduino. The Arduino then sends out the doorbell code with the transmitter. It’s evil, and extraordinarily over-engineered.

Right now, the ding dong ditch project is set up somewhere across the street from [Matt]’s house. The device reportedly works great, and hopefully hasn’t been abused too much. Video below.

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RasPiCommPlus, An Expansion Board For Expansion Boards

November 17, 2014 by Brian Benchoff 34 Comments

The easiest way to connect a GSM module to a Raspberry Pi would be to buy a breakout module, install some software, and connect to a mobile network with a Pi. Need GPS, too? That’s a whole other module, with different software. The guys behind RasPiCommPlus are working on a better solution – a breakout board for breakout boards that takes care of plugging a ton of modules into a Pi and sorts out the kernel drivers to make interfacing with these modules easy.

Right now, the team has a GPS and GSM module, digital in and out modules, an analog input module, and RS-232 and -485 modules. They’re working on some cool additions to the lineup, including a breakout for Sharp memory displays, a 9-axis IMU, a stepper motor driver, and a 1-wire breakout module.

Some of the RasPiCommPlus team showed up to the Hackaday Munich party and were kind enough to sit down for a demo video. You can check that out below.

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Arduino-Powered Alarm System Has All The Bells And Whistles

September 2, 2014 by Bryan Cockfield 24 Comments

Put aside all of the projects that use an Arduino to blink a few LEDs or drive one servo motor. [IngGaro]’s latest project uses the full range of features available in this versatile microcontroller and has turned an Arduino Mega into a fully-functional home alarm system.

The alarm can read RFID cards for activation and control of the device. It communicates with the front panel via an I2C bus, and it can control the opening and closing of windows or blinds. There is also an integrated GSM antenna for communicating any emergencies over the cell network. The device also keeps track of temperature and humidity.

The entire system can be controlled via a web interface. The Arduino serves a web page that allows the user full control over the alarm. With all of that, it’s hard to think of any more functionality to get out of this tiny microcontroller, unless you wanted to add a frickin’ laser to REALLY trip up the burglars!

A GSM Base Station With Software Defined Radio

July 5, 2014 by Brian Benchoff 40 Comments

gsm If you’re wondering how to get a better signal on your cellphone, or just want to set up your own private cell network, this one is for you. It’s a GSM base station made with a BeagleBone Black and a not too expensive software defined radio board.

The key component of this build is obviously the software defined radio. [Julian] is using a USRP B200 radio for this project. It’s not cheap, but it is a very nice piece of hardware capable of doing just about anything with GNU Radio. This board is controlled by a BeagleBone Black, a pretty cheap solution that puts the total cost of the hardware somewhere around $750.

The software side of the build is mostly handled by OpenBTS, the open source project for the software part of a cell station. This controls the transceiver, makes calls and SMS, and all the backend stuff every other cell station does. OpenBTS also includes support for Asterisk, the software of choice for PBX and VoIP setups. Running this allows you to make calls and send texts with your SDR-equipped, Internet-enabled BeagleBone Black anywhere on the planet.