Making High Concentrations Of Hydrogen Peroxide At Home

February 3, 2013 by 88 Comments

Hydrogen peroxide – the same stuff you can pick up from a drug store or beauty supply store – is one of those very interesting chemicals that belongs on every maker’s cabinet. At concentrations of about 30%, it’s perfect for etching PCB boards, and at even higher concentrations – about 70% – it can be used as rocket fuel. Unfortunately for the home hacker, it’s very difficult and expensive to obtain peroxide in concentrations above 3% or so. That’s alright with [Charlie], though, because he’s come up with a way to concentrate peroxide and measure the concentration once he’s done.

There are a few YouTube videos of kitchen chemists concentrating peroxide by heating it on a stove to just under 100°C. Because hydrogen peroxide boils at 150°C, they’re simply boiling off the water and increasing the concentration of peroxide. This is a qualitative method, and you’ll never know what concentration you’re getting. [Charlie] rigged up a small-scale with a pipette to measure the weight of his concentrated peroxide per unit of volume, giving him the density of his concoction and thus the concentration.

We have to note that concentrated peroxide is dangerous stuff, but the results of [Charlie]’s lab work aren’t much more dangerous than what hair stylists work with every day. If you’re going for high-test peroxide, good job, that’s awesome, but do be aware of the risks.

The Universal Geospatial Light Switch

February 3, 2013 by 14 Comments

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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Ammo Box PSU

February 3, 2013 by 30 Comments

PAB-PSU-1

Sometimes you need a power supply that can be thrown into the back of a car and taken into the field. [BadWolf] didn’t want to take his bench supply, so he whipped up this very portable power supply made from a computer PSU. To ruggedize his build a little, he put it in a 50 caliber ammo can making it more than able to handle the roughest field work.

While not a proper adjustable power supply, this ammo can is more than capable of delivering a whole lot of current in a number of different voltages. There are a few bells and whistles – a ‘plugged in’ and ‘on’ light, as well as a few very cool looking toggle switches that are sure to arouse the suspicions of unsuspecting bystanders.

[BadWolf] kept all the safety features built-in to the computer PSU, so this ammo box power supply is still protected from short circuits, and over-current, making it much safer than its appearance belies. It’s also a great example of what can be done if you don’t have a proper bench supply, so we’ve got to tip our hat to [BadWolf] for that.

BladeRF, Your Next Software Defined Radio

February 2, 2013 by 74 Comments

By now you might have a bit weary of your small and inexpensive TV tuner dongle software defined radio. Yes, using a USB TV dongle is a great introduction to SDR, but it has limited bandwidth, limited frequency range, and can’t transmit. Enter the bladeRF, the SDR that makes up for all the shortcomings of a USB dongle, and also serves as a great wireless development platform.

The bladeRF is able to receive and transmit on any frequency between 300 MHz and 3.8 GHz. This, along with a powerful FPGA, ARM CPU, and very good ADCs and DACs makes it possible to build your own software defined WiFi adapter, Bluetooth module, ZigBee radio, GPS receiver, or GSM and 4G LTE modem.

It’s an impressive bit of kit, but it doesn’t exactly come cheap; the bladeRF is available on the Kickstarter for $400. The folks behind the bladeRF seem to be doing things right, though, and are using their Kickstarter windfall for all the right things like a USB vendor ID.

There’s a video of two bladeRFs being used as a full duplex modem. You can check that out after the break.

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Guitar Hero Controller Built From Toy Guitar And Keyboard

February 2, 2013 by 13 Comments

frets-on-fire-custom-controller

[Heinrich Laue] was kind of a latecomer to the fake guitar playing video game phenomenon. He played Frets on Fire — an open source clone of the game — on PC and eventually bought a copy of Guitar Hero World Tour. But playing on the keyboard was a drag. Instead of buying a controller he built his own hacked Guitar Hero controller from a scrapped keyboard and a toy guitar.

The plastic toy he started with was screwed together. This is a really nice since it’s almost impossible to open toys that have been welded together. There was plenty of room inside for all his components and even some space to run the wires.

He started the electronic portion of the build by tracing out the keyboard matrix to figure out which solder pads he could tap into. The strum bar uses a door hinge with buttons on either side of it. When you move it back and forth it hits the buttons, with the spring mechanism in each returning it back to center. The fret buttons are keys from the keyboard, but the switches uses were pulled from a few computer mice. But the real innovation comes into play when he added the Star Power tilt sensor and whammy bar. Follow the link above to find out how he did it.

Easy Web Interface With GPIO Access Runs On Raspberry Pi

February 2, 2013 by 30 Comments

Here’s a Raspberry Pi hack that adds web control using PHP and MySQL. As you can see in the image, it serves up a webpage (using the Apache2 server) which allows you to change the state of the GPIO pins. It’s not super-complicated, but it is nice to see a step-by-step guide for installing and configuring the package.

Web interface GPIO control is one of the features we loved about the Adafruit Web IDE. But this offering is loaded completely from the RPi (the Adafruit package uses cloud based code) and utilizes the tools most Linux network admins will be used to. A MySQL database manages the connection between GUI commands and GPIO modification. The webpage is served up by a PHP script which takes care of polling and changing database values. Configuration requires a new database, plus the username and password which has access to it.

Music Challenge Has You Flapping Your Wrist To Make Sounds

February 2, 2013 by 7 Comments

glove-based-music-challenge

This glove controller let you play a musical game. The challenge is to perform the correct wrist motions at the right tempo to play the intro to the song Where is my Mind by the Pixies. This is demonstrated in the video clip after the break.

We often see flex sensors used on the fingers of glove projects, but this one does it all with an accelerometer. That module, along with the Piezo buzzer used for playback are affixed to the small breadboard on the back side of his hand. Rubber bands connect the Arduino to his third and forth fingers. The tempo and rhythm are pre-programmed but the tone generated is based on the gravity reading at the start of each note. If you don’t have your hand positioned correctly the wrong tone will be played.

The code was published in link at the top. It would be fun to see this altered as a hacked Simon Says game.

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