Bluetooth headset garage door opener update

bluetooth-headset-garagedoor-opener-update

[Lou Prado] sent in a link to his new video on using a Bluetooth headset as a garage door opener for your Android device. This isn’t a new hack, and we’ve actually seen him pull it off once before back in 2011. But we’re running this as an update for a couple of reasons. First off, we had forgotten about the hack and it’s worth revisiting. Secondly, the headset which he used with the initial hack has gone out of production. He chose a new model, and the assembly video (embedded after the break) which he made is a treasure trove of best practices to use when hacking consumer electronics.

Here’s how the hardware part of the hack goes. He removes the speaker from the headset and solders the base of a transistor in-line with a resistor to the red wire. The emitter connects to the grounded frame of the USB charging cable which is plugged into an outlet next to your garage door opener. The collector of the transistor is then connected to the garage door opener, along with a common ground connection, allowing audio from the headset to trigger the transistor to open the door.

The systems is secure based on Bluetooth pairing, which was done with his phone before starting the hardware hack.

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Carry a Git server in your pocket

android-git-server

We love using Git for its superior version control. We often host our more advanced projects in a public Github repository. But the bulk of our little experiments are simply local repos. This is fine if you’re always at home, but if we are away from home we find ourselves having to SSH into our server to copy over the Git files. [Andrew] found a way around this slightly awkward process. He used an old Android phone as a Git server.

This actually makes a lot of sense when you start to think about it. Most Android phone have a microSD card slot to provide a huge storage bin (the lack of this on the Nexus 4 is baffling) so you don’t need to worry about running out of space. All of these devices have WiFi, making it easy to use them as an AP when there isn’t any other WiFi around. And the web-connected nature of the device will make syncing your repo over the Internet a snap.

Most of the behind the scenes work is done using Debian packages. This provides a few issues which [Andrew] walks through one by one. We also like his pointers like using ‘noatime’ on your EXTx file systems to avoid wear on the SD card.

Wireless pinball controller for tablet gaming

wireless-pinball-controller

This wooden box is a wireless pinball controller and tablet stand. The idea is to set it on a workbench to give you some of the thrill of standing and playing the real thing. [Jeff] has been rather addicted to playing a pinball app on Android lately, and started the journey because he needed a way to give his thumbs some relief.

An Arduino monitors buttons on either side of this wooden controller. [Jeff] is new to working with hardware (he’s a Linux Kernel developer by trade) and was immediately struck with button debouncing issues. Rather than handle this in software (we’ve got a super-messy thread on that issue with our favorite at the bottom) he chose a hardware solution by building an SR latch out of two NAND gates.

With the inputs sorted out he added a BlueSMiRF board to the project which allowed him to connect a Nexus 7 tablet via Bluetooth. At this point he ran into some problems getting the device to respond to his control as if it were an external keyboard. His stop-gap solution was to switch to a Galaxy Tab 10.1 which wasn’t throwing cryptic errors. Hopefully he’ll fix this in the next iteration which will also include adding a plunger to launch the pinball, a part which just arrived in the mail as he was writing up this success.

We’ve embedded his quick demo video after the break.

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Freezing Android to crack the encryption

frozen-phone-encryption-hacking

Build a better lock and someone will make a tool to open it without the key. Or in this case they’ve made a tool to discover the key using a trip to through the deep freeze. The Forensic Recovery of Scrambled Telephones — or FROST — uses cold temperatures and a custom recovery image to crack Android encryption keys.

Cold boot hacks go way back. They leverage use of low temperatures to slow down the RAM in a device. In this case, the target phone must already be powered on. Booting a phone that uses the encryption offered by Android 4.0 and newer requires the owner’s pass code to decrypt the user partition. But it then remains usable until the next power cycle. By freezing the phone, then very quickly disconnecting and reconnecting the battery, researchers were able to flash their own recovery image without having the encryption key cleared from RAM. As you can see above, that recovery package can snoop for the key in several different ways.

[Thanks Rob]

Beginner’s Android/Arduino example shows the power of App Inventor

app-inventor-android-bluetooth-example

This is a simple project. It uses an Android device to switch an LED driven by the Arduino. Connectivity is provided by the Bluetooth module inserted in the breadboard. But one look at the UI on the Android device and you might think this is anything but simple. The truth is that [Kerimil] didn’t spend forever learning Java and programming the app. Instead he’s showing off the power of  App Inventor to get your Android controls up and running fast.

Check out the third button down; when was the last time you added voice commands to your project? It’s worth clicking through to see just how simple that portion was. App Inventor — a Google cast-out that is now maintained by MIT — is a graphical tool that unlocks the power of an Android handset to those with the most basic of programming understanding. For instance, the voice controls shown off after the break are provided by a single bracket which uses conditional statements to ‘listen’ for the words on, off, and blink. You’ll find the voice recognition diagram after the break as well.

You could try to go completely graphical with this project. There’s the option of programming the Arduino side of the project in a similar way.

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The Universal Geospatial Light Switch

project rita

Home automation has existed in one form or another for quite some time, but we thought this take on controlling lights was quite interesting.  Instead of having a menu of lights that you can turn on and off, this Android app lets you point your phone at the device and turn it on or of. Undoubtedly similar to how [Darth Vader] controls his lights at home.

Although the really technical details of this project aren’t listed, this setup reads the compass and GPS output of the Android device to figure out where it’s pointed in space. Combined with a script that understands the layout of the room, and an [X10] automation controller, it’s able to control lights accurately.

Be sure to check out the video of this device in action, or check out [Mike]‘s [Project Rita] blog to see the other interesting projects that he’s working on!

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XBMC workaround for Android hardware video acceleration

xbmc-android-video-hardware-acceleration-workaround

An unofficial, but fully functional release of XBMC should make the uber-popular media center software work with almost all Android devices. About six months ago the developers of XBMC announced that it had been ported for Android. That was true, but there was one caveat. The port was made functional on one specific Android device. The hardware company Pivos paid for the devs to add support for their Xios DS device. Although that build could be run on other Android devices, the hardware video acceleration could only be use if it was the same as the Xios. When not using the hardware acceleration many common video formats would only play at a few frames per second, if at all.

This build is a workaround and is not officially supported. What it brings to the table is the ability to use an external media player with XBMC. This way any video format which your Android device is capable of playing (with hardware acceleration) can be launched from XBMC but will be played by the native video application. We haven’t tried it for ourselves. If you have we’d love to hear about your experience in the comments.

[via Ars Technica]