Rattle generator is a new type of dynamo for a bicycle

rattle-generator-bicycle-spokes

This project is in one of our favorite categories; the kind where asking “why?” is the wrong question. [Berto A.] built the device after observing some power generation by placing a large magnet next to a mechanical relay coil and quickly clicking the relay’s lever. From this humble beginning he built up the RattleGen, a bicycle spoke driven generator.

To get the most power possible he searched around for a massive relay and found one which was originally meant for telephone exchanges. He cut the case open and strapped a big bar magnet to the side of the coil. Next he fabricated an arm which will press against the relay’s lever. To that he added a small wheel which is pressed each time a spoke from the bicycle passes by it. This repeated clicking of the relay lever generates a current (and a rattling sound) that is harvested by the joule thief circuit built on some protoboard. An LED is illuminated, with excess current stored in the capacitor bank. Don’t miss the build and demonstration video after the break.

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OTM-02 is a 3D printed wristwatch

3d-printed-wristwatch

We love looking at roll-your-own wristwatch projects. Getting a project small enough to carry around on your wrist is a real challenge. But we think the OTM-02 wristwatch really hit the form factor right on the mark.

OTM stands for Open source Time Machine. It’s the work of [Hairy Kiwi] and he managed to bring the guts of the watch in at a thickness between 6.5 and 7mm. That includes the LCD, PCB, piezo diaphragm, and the battery. The PCB itself is a four-layer board built on 1mm thick substrate. It’s running an EFM32 (ARM) microcontroller which comes with hardware USB support. The little door sitting open on the side of the 3D printed enclosure provides access to the micro USB connector which can be used to charge the 150 mAh battery inside. That may not sound like much juice, but if you set the display to show minutes only [Hairy] calculates a battery life approaching 175 days. If you just have to have the seconds displayed you can expect about two weeks between charges.

Like the name says, this project is Open Source.

[Thanks Liam]

What are the best hacking documentaries?

Continuing with our series of best and worst portrayals of hacking, we’re gathering our resources to bring you the top 10 Hacking Documentaries. Again, we feel the strongest resource is the hacking community, so lets hear what you think should qualify.  While it would be fantastic to only have documentaries, if there is a hollywood movie that you feel fits, go ahead and let us know. If you’re up for a challenge, find us something dealing with hardware hacking instead of computers/phones!

Just for reference, here were the top 10 worst portrayals of hacking in movies as well as part 2. What you see above were the top 10 best, though admittedly I screwed up #4.

 

Console radio given new life with a WiFi router retrofit

tube-radio-wifi-router-retrofit

[Craig] did a great job of restoring the case of his antique console radio. But he wanted to bring the guts up to modern standards. The fix ended up being rather easy when it comes to hardware. He based his internet radio retrofit around a wireless router.

We laughed when we heard that he removed about eighty pounds of original electronics from this beast. He then cut a piece of MDF to serve as a mounting platform for the replacement hardware. The WiFi router takes care of audio playback from several sources and offers him the ability to control the stereo from a smart phone or a computer. It has a USB port to which he connected a hub to make room for the USB sound card and a thumb drive which holds his music library. The black box in the upper right is an amp which feeds the NHT stereo speakers housed in the lower half of the cabinet.

It doesn’t make use of the original knobs like the recent tube-amp conversion we looked at. But [Craig] did add some LEDs which illuminate the dial to help keep that stock look.

20 pounds and a gut feeling yields a configurable Rubidium atomic clock source

rubidium-source-for-twenty-pounds

So you see an image like this and the description “Aircraft stable oscillator” on an eBay listing for twenty pounds (about thirty bucks), what do you do? If you’re [Alecjw] you buy the thing and crack it open to find an atomic clock source inside. But he really went the distance with this one and figured out how to reconfigure the source from the way it was set up in the factory.

First off, the fact that it’s made for the aerospace industry means that the craftsmanship on it is simply fantastic. The enclosure is machined aluminum and all of the components are glued or otherwise attached to the boards to help them stand up to the high-vibrations often experienced on a plane. After quite a bit of disassembly [Alec] gets down to a black box which is labeled “Rubidium Frequency Standard”… jackpot! He had been hoping for a 10 MHz signal to use with his test equipment but when he hooked it up the source was putting out 800 kHz. With a bit more investigation he figured out how to reconfigure the support electronics to get that 10 Mhz source. We think you’re going to love reading about how he used a test crystal during the reconfiguration step.

Once he knew what he had he returned to the eBay seller and cleared out the rest of his stock.

[Thanks DIY DSP]

Connect a Retina display to a regular computer

retina-display-as-auxiliary-pc-display

You don’t have to search very long before you find someone raving about the Retina display used in Apple iPads. We’re not going to disagree. These 9.7″ panels pack in a whopping 2048×1536 resolution and the color is fantastic. But we were surprised to hear you can get one of these for a meager $55. That’s how [Andrzej] sourced the part when he set out to connect a Retina display to a regular PC.

It turns out this isn’t all that hard. The display uses the eDisplayPort protocol. This is an extension of DisplayPort which is an alternative to LVDS that is gaining a foothold in the industry. An external DisplayPort adapter can already be found on higher-end laptops, which means this should be a snap to use as an external display if the signals can be routed correctly.

To do this, [Andrzej] figured out how to order the PCB connector for the panel’s ribbon cable. He then etched and populated his own board which serves as an adapter for a DisplayPort cable. It even powers the panel, but an external 20V supply is necessary for the backlight.

[Thanks Adam]

Automatic tubular bells given a MIDI interface too

automatic-tubular-bells

We’ve got to say it… these tubular bells sound awful! They don’t really have a tight pitch center so they sound really out of tune to us. But we think that’s the failing of the instrument itself and not the work which [Tolaemon] did to automate the instrument.

There are three main parts to his project. The first, which is shown above, adds a hammer for each bell. The hammers are hinged, with one side being pulled by a solenoid in order to strike the bell. The second part of the hack also uses solenoids, dampening the bell’s ability to ring by pressing a felt pad up against the bottom of the tube. The final portion of the project brings it all home by adding MIDI control to the hardware.

The clip after the break gives a good overview of the different features including some preprogrammed playback as well as direct control of the instrument using an electric keyboard. This reminds us of that scratch-built solenoid xylophone.

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