Adding Node.js Based Sensors To The Parrot AR Drone

November 28, 2012 by 7 Comments

[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

November 28, 2012 by 8 Comments

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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Turning Toy Pianos Into MIDI Keyboards

November 28, 2012 by 8 Comments

Building a MIDI device is always a great microcontroller project, and nearly everyone has an old toy keyboard lying around in the back of a closet or in the basement. [JenShen] decided to take one of these toy keyboards and build a MIDI keyboard.

The keyboard [JenShen] used was a simple Casio keyboard with built-in voices. After tearing out the guts of the keyboard, the only thing that remained is the row of push buttons underneath the keys. These buttons were laid out in a row/column matrix, so [JenShen] needed to decode this matrix before sending the result to an Arduino for processing.

A 74HN595 shift register was used to read the 8 rows of buttons underneath the keys, while the rows were tied to different input pins on the ‘duino. This allowed [JenShen] to scan the keyboard matrix with an Arduino and generate MIDI notes and send them to other synths.

In the video after the break, you can check out [JenShen]’s circuit and code that allowed him to turn a toy keyboard into a proper 32-note MIDI keyboard. It’s not velocity sensitive, but he says he’ll show everyone how to accomplish that in a future post.

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Glockentar: A Guitar + Glockenspiel Mashup

November 28, 2012 by 7 Comments

This unique electronic instrument combines a chopped up guitar and a hacked apart glockenspiel with an Arduino. [Aaron]’s Glockentar consists of guitar hardware and glockenspiel keys mounted to a wood body. Solenoids placed above the keys actuate metal rods to play a note.

Under the hood, an Arduino connects the pieces. The conductive pick closes a circuit, which is a digital input into the Arduino. This actuates the corresponding solenoid to play the glockenspiel key, and sends a character to a computer over serial.

On the computer, an openFrameworks based program creates lighting that is projected onto each string. MadMapper is used for projection mapping, which maps the openFrameworks output to each string. Video is passed between applications using the Syphon framework.

[Aaron] has provided a write up that goes into details, including the Arduino and openFrameworks source for the project. There’s also a video overview and demo of the Glockentar after the break.

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Cheap Biquad Antenna Extends LAN Between Apartments

November 27, 2012 by 41 Comments

[Danilo Larizza] is sharing a network connection between a couple of apartments. They are not far apart, but they are also not right next to each other so a set of external antennas is necessary. He built this 2.4 GHz biquad antenna on the cheap (translated) just to test if it improved the signal before he tried to buy a proper antenna. It turns out to work well enough that this is all that he needs.

The antenna itself is about one meter of thick wire bent into two squares which are 31mm on each side. The coaxial cable going to the router connects to the center portion of this antenna. For a bit better directional reception he added some tin foil as a reflector. Since this is outdoors he used a food storage container for protection (the antenna is mounted to the lid, the body has been removed for this picture). The whole things is perched on a stake in a flower pot with proper line of sight to the other antenna.

We’ve seen a very similar design used for an NRF 24L01+ radio. If you need more details that [Danilo] posted that would be a good project to study.

Injecting Power Into A WiFi Dongle For The Raspberry Pi

November 27, 2012 by 20 Comments

So the Raspberry Pi sometimes doesn’t have the juice needed to run power-hungry USB dongles. The most common issue is with WiFi adapters. The solution has long been to use a powered USB hub, but [Mike Worth] didn’t want to take up that much extra space. The solution he worked out injects power directly into the dongle itself.

The red and white wires coming out of the side provide the 5V source. This is coming from the same USB mains power adapter that supplies the RPi board itself. To connect the wires to the dongle he made an adapter out of some strip board and the shielding from the dongle. The end of the strip board pokes out of the shielding far enough for him to solder on some wire, which is then soldered to the traces on the dongle’s PCB.

You can just plug this in and get down to business. But while he was at it [Mike] added an improvised antenna for better reception. It’s the same type of hack we saw him use for a Bluetooth dongle in this links post.