Hacking BodyBugg fitness sensors to get around subscription fee

This arm cuff is a sensor package which logs data whenever you’re wearing it. It records accelerometer data, skin temperature, and galvanic skin response. That data can then be analyzed to arrive at figures like calories burned. But… The company behind the device seems to have included a way to keep the cash flowing. Once you buy it you can read the data off of the device using a Java program they supply. But you can’t erase the data from the device unless you subscribe to their online service. Once it fills up, it’s useless. [Doug] wasn’t happy with this gotcha, so he reverse engineered the technique used to clear the BodyBugg’s memory.

There had been a few previous attempts at reverse engineering the device but that groundwork didn’t really help [Doug] on his quest. He ended up disassembling the Java classes from the original program. This helped him figure out how to initialize communications. Once there he was happy to find that the device will tell you how to use it. If you issue an invalid command it will respond with a list of all valid commands. Everything you need to get up and running can be found in his github repo.

100 meter spring reverb makes us hear satanic voices

Spring reverb is something we’re used to hearing about when it comes to guitar amplifiers. It’s a coil spring stretched the length of the amp’s housing. One end is fed the guitar signal, with a pickup at the other to capture the output. But this spring reverb is on a much grander scale. [Jochem van Grieken] strung up 100 meters of coiled steel wire in a long hallway and the results sound a little bit evil.

A simple piezo element is used as a pickup to amplify the sound coming off of the spring. Above [Jochem] is using what looks like a jeweler’s saw to make some sound on the 3.5mm wire. It’s this portion of the video that sounds demonic to us. In the second half of the demonstration he strikes the wire with a ruler to produce the pew-pew effect from many a sci-fi movie.

This isn’t his first experiment with the concept, it’s just his largest. Also found after the break are a pair of links to his other installations.

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MOD player for the Stellaris Launchpad

[Ronen K.] wrote in to tell us about the MOD playing Stellaris Launchpad project he recently completed. A MOD is a sound file for the computers of days long gone. But you’ll certainly recognize the sound of the 8-bit goodness that is coming out of this device.

To understand how a MOD file stores samples you might want to glance at the Wikipedia page. There are a ton of these files out there, but this implementation is meant for files with only four channels. For now the only external hardware used is an audio jack which needs a ground connection and a PWM signal on each of the two audio channels. [Ronen] is storing the files in flash memory rather than using an SD card or other external storage. This leaves 213k of space for up to six files that can be selected by the user buttons which cycle forward or backward through the list. See this demonstrated after the break.

The project ports existing code from an STM32 application. Since that is also an ARM microcontroller there’s not a ton of work that needed to be done. But he did have to write all of the PWM functionality for this chip. This PWM tutorial turned out to be very helpful during that process.

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Internet radio occupies an 80-year-old radio case

[Florian Amrhein] made use of some old hardware to build his own internet radio in a 1930’s radio case.

The original hardware is a tube-amplified radio which he picked up on eBay. There’s tons of room in there once he removed the original electronics and that’s a good thing because he crammed a lot of new parts into the build. The main one being an old laptop he had on hand. It’s got a 10″ screen which is too large for the opening, but that ended up being okay. He coded an interface with C and SDL which give him a visual representation of his favorite online streams. The knob to the right moves the red line when turned and causes the Debian box to change to the new stream using the Music Player Daemon. Two potentiometers control the tuning and volume, and there is also a rotary encoder which is not yet in use. All three are connected to the laptop via an Arduino.

Check out the finished product in the video after the break. It sounds quite good thanks to the small automotive speaker and amplifier also crammed into the old case.

If you don’t have a laptop lying around to use in a project like this consider a microcontroller and character LCD based system.

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Adding Node.js based sensors to the Parrot AR drone

[Max Ogden] wanted the option to add sensors to his Parrot AR Drone. This a commercially available quadcopter which runs Linux. This makes it rather easy for him to use Node.js to read the sensors from an Arduino board. The use of the Arduino is merely for easy prototyping. It is only needed to bridge the drone’s serial port with a sensor’s delivery method, so just about any microcontroller could be substituted for it.

There are some hardware considerations to take into account. The manufacturer was nice enough to populate a 0.1″ pitch pin socket on the serial port (if only this kind of invitation to mess with hardware was an industry standard). But the device expects 3.3V levels so pick your hardware accordingly. There is one commenter who tried the project for themselves and found that the drone wouldn’t boot up with the Arduino already connect — he had to boot and then complete connections. Troubles aside this makes adding your own sensor payload very simple and you don’t have to wait until landing to get at the data.

Maybe we’ll have to add some shock voltage data reporting to our shockerDrone.

Headphone light show

Seriously, nothing says ‘Look at me!’ like these headphones. [Yardley Dobon] added a rainbow of colored electroluminescent wire to his headphones and made them pulse to the music. The video after the break shows the headphones bumping to the tunes. This is one of two versions of the project, the other runs the EL wire along the headphone wire itself. We’re a bit surprised that the high frequency from that parallel run doesn’t inject noise into the signal. We do enjoy seeing these in action, but in practice observers unfortunately won’t be able to hear the tunes to which the lights are pulsing.

It took us a little while to figure out that [Yardley] didn’t roll his own VU hardware. The inverter driving the EL wire is designed to bump to the music. But he did hack it to use an audio line rather than a microphone. He mentions that this has other uses, like allowing carefully crafted sound clips to precisely control the inverter.

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