Month: August 2013

Milled Water Bottle Rocket Launcher Pushes Plastic Containers To Their Limit

August 27, 2013 by 31 Comments

water-bottle-rocket-launcher

Building this launcher is simple if you already have a mill. It does a remarkable job of pressurizing and launching soda bottles which are partially filled with water. The main component of this is a triple-gasket stopper with a quick release.

The problem with a lot of these water bottle rocket projects is that they leak where the bottle meets the launcher. In most cases this is a good thing as it’s almost impossible to build up enough pressure to cause the bottle to fail. This system has no such built-in safety mechanism, which is why the test launch below is conducted from a safe distance. After seating the partially filled bottle on the launch platform it’s pressurized to around 100 PSI at which point a yank on the string lets it fly.

Most of the time we look on these as casual projects. But we figure this one is much more suited for a rocket club or hackerspace event.

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Building A ‘high-end’ USB Audio DAC

August 27, 2013 by 63 Comments

As [Jan-Erik] had already built a simple USB connected Digital-to-Analog Converter (DAC), he decided to make the high-end version of it.

The prototype you see in the picture above is based on:

  • the PCM2707C from Texas Instruments which takes care of the USB communication and outputs I2S audio data
  • the PCM1794A, a 132dB SNR 24-bit 192kHz DAC which receives I2S protocol
  • the OPA4134, a high performance audio operational amplifier

The on-board +3.3V and -5V voltages are generated by inductor-less power supplies. As [Jan-Erik] mentions in his write-up, the ‘high-end’ was put between single quotes because the PCB is single sided and uses through hole passive components. The board was designed using Kicad, etched by himself and put in a machined enclosure. All the production files can be downloaded from his website so you may produce it within a day.

CC3000 WiFi Driver For .NET Micros

August 27, 2013 by 10 Comments

CC3000

The Netduino and other .NET Micro boards don’t seem to get much love, but that doesn’t mean they’re not able to use one of the coolest chips we’ve seen in a while. [Valkyrie] has written a driver for TI’s new CC3000 all-in-one WiFi chip, giving any .NET micro device a very small and very cheap WiFi connection.

A while back, [Chris Magagna] created a TI CC3000 library for the Arduino. [Valkyrie] fell out of his chair when he saw that post, as it meant the .NET Micro devices such as the Netduino could finally use this device. With a TI Launchpad and a logic analyzer, [Valkyrie] recorded all the SPI commands and responses eventually reconstructing the entire library.

As for how useful this is without any hardware, There’s already a CC3000 Gadgeteer module available from GHI Electronics.

Spoofing WiFi AP Based Geolocation

August 27, 2013 by 39 Comments

[Pierre Dandumont] just finished up a little project that will give Google Maps’ location feature a run for its money. It’s a technique that spoofs WiFi networks in order to relocate the positional data reported via WiFi networks.

He starts with an explanation of the different ways modern devices acquire location data. GPS is the obvious, and mobile network triangulation is pretty well know. But using WiFi networks may be a new trick for you. We’re not 100% certain but we think Google is able to look up location data based on known IP addresses for WiFi access points (this would be a good comments discussion). To trick the system all you have to do is feed some captured AP data into the computer before Google Maps tried to lock onto a location. The video after the break shows Maps with the legit location displayed. After running a quick script whose output is shown above the map position is changed to the spoofed location.

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Stopping A Hackerspace From Rusting Away

August 27, 2013 by 17 Comments

steel

The illutron hackerspace in Copenhagen makes their home on a barge sitting in port. Not only is this awesome, but the members of the hackerspace also worry about corrosion to their beloved fablab. In an effort to ally some fears about rust slowly eating through the hull, [Dzl] has rigged up a cathodic protection system for their hull, essentially preserving their barge at the expense of a few old steel rails.

Cathodic protection systems are able to protect the steel of a ship’s hull by offering up a sacrificial anode made of aluminum or zinc. This can be done by either attaching a sacrificial anode directly to the hull, or with a more complex system that connects both the cathode (the ship) and the anode (an engine block) to a DC power source.

[Dzl] is converting mains voltage down to 12 VDC, then further lowering the voltage with an Arduino-controlled buck converter. The control panel allows for adjustments in the voltage, as well as a nice uptime meter to make sure it’s running.

The results are fairly impressive; in the above pic, the right piece of steel was electrically connected to the barge’s hull, while the left piece was free to rust in the North Sea. That’s only two days worth of corrosion there.

Making A HP Frequency Counter More Accurate

August 26, 2013 by 38 Comments

[Gerry] built his own high stability timebase add-on for his HP 53131 frequency counter. This project started out after [Gerry] built a rubidium 10 MHz standard for his lab. Upon connecting the standard to the frequency counter for calibration, he found that the HP 53131 had an awful internal oscillator. The official high stability timebase add-on from HP cost about $1000, and he was determined to do better.

Using a second hand OCXO as the oscillator, he designed his own add-on module. OCXO modules pack a crystal oscillator in a thermal chamber. Since temperature fluctuation causes drift in crystal oscillators, an OCXO controls the temperature to keep the frequency constant. They can be bought second hand on eBay for under $30.

The PCB design for the module can accommodate a variety of OCXO modules. It uses a high speed comparator and a high stability 5 volt reference to provide the clock signal to the counter. A DAC is used to calibrate the oscillator. By keeping the same DAC as the original counter, the add-on board can be calibrated using the front panel of the device.

The project is a drop in replacement for HP’s $1000 module for a fraction of the cost. [Gerry]’s write up has all the details you’ll need to build your own.

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Sony SmartWatch Hack Lets It Tell Time With A Teapot Animation

August 26, 2013 by 27 Comments

sony-smartwatch-wireframe

This hack turns the Sony SmartWatch into a wristwatch. Functionally it’s not all that impressive. But the journey to get to this point represents quite a bit more. This example features an animated tea pot using a 3D rendering engine ported over to the device.

[Federico] started work on the project soon after hearing that Sony had released details about developing for the hardware. He dug into the documentation but soon found it lacked the depth he needed to get a handle on bare metal work. He shelved the project for a while until coming across the Astrosmash project we featured in June. That used a wrapper that allows Arduino sketches to run on the watch. After studying how that’s done he had enough background to port this code.

We’re still waiting to see a really innovative hack for the watch. But we’re glad to see progress with each new proof of concept like this one!

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