VCR Centrifuge

vcrCentrifuge

VCR’s practically scream “tear me open!” with all those shiny, moving parts and a minimal risk that you’re going to damage a piece of equipment that someone actually cares about. Once you’ve broken in, why not hack it into a centrifuge like [Kymyst]? Separating water from the denser stuff doesn’t require lab-grade equipment. As [Kymyst] explains: you can get a force of 10 G just spinning something around your head. By harvesting some belt drives from a few VCR’s, however, he built this safer, arm-preserving motor-driven device.

[Kymst] dissected the video head rotor and cassette motor drive down to a bare minimum of parts which were reassembled in a stack. A bored-out old CD was attached beneath the rotor while a large plastic bowl was bolted onto the CD. The bowl–here a microwave cooking cover–acts as a protective barrier against the tubes spinning inside. The tube carriers consist of plastic irrigation tubing fitted with a homemade trunnion, which [Kymyst] fashioned from some self-tapping screws and a piece of PVC. At 250 rpm, this centrifuge reaches around 6 G and best of all, gives a VCR something to do again. Take a look at his guide and make your own, particularly if your hackerspace has a bio lab.

DIY Ultrasonic acoustic levitation

ultrasonic

[Mike] saw a few videos of ultrasonic acoustic levitation rigs put together by student researchers. Figuring it couldn’t be that hard to replicate, he set out and built his own using surplus parts and whatever was sitting around his parts drawer.

The build began with a huge ultrasonic transducer from an old ultrasonic cleaning tank [Mike] picked up on eBay for $20 £20. He didn’t pick up the standard driver board, as those don’t have a very clean output – something desperately needed if you’re setting up a standing wave. He did manage to put a simple supply together with a 555 timer, a MOSFET and a 12 V transformer connected backwards, though.

The test rig is pretty simple – just the transducer sitting on a table with an aluminum plate sitting above it on threaded rods. By adjusting the distance between the transducer to the aluminum plate, [Mike] managed to set up some standing waves he was able to suspend small Styrofoam balls in. It’s not quite precise enough to levitate small chunks of sodium and water, but it makes for an excellent science fair-type project.

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A touch screen Geiger counter without a Geiger tube

geiger

We’re assuming [Toumal] was desperately bored one day, because in the depths of the Internet he found some really cool components to build a solid state Geiger counter.

The Arduino and touchscreen are rather standard fare [Toumal] picked up on eBay for about $30. What really sets this project apart from all the other geiger counter builds we’ve seen is the solid state geiger counter [Toumal] used. This device uses a specially-made photodiode made by First Sensor to detect gamma emissions from 5 to 1000 keV.

[Toumal] put all the software for his Arduino touch screen radiation detector up on github. To be honest, we’re really impressed with the rad sensor [Toumal] used for this project, so if you ever decide to pick one of those up, he’s got your back with an Arduino library for it.

Potassium Chlorate from household products

potassium-chlorate-crystalization-experiment
To the upper right we have very pure potassium chlorate, so much so that it bursts into flames when mixed with sugar and catalyzed with some sulfuric acid. [Mr. Home Scientist] produced the KClO3 using household chemicals and some rudimentary equipment sourced on eBay.

The experiment started off with concentrated bleach containing 8.25% sodium hypochlorite. He needed sodium chlorate so a hot plate was used to boil the bleach until crystals started to form. A more efficient way to achieve this reaction would be using electrolysis (check out the HHO generator we saw recently for a homemade rig). The next step is to add potassium chloride, which is sourced from the grocery store as a sodium-free salt alternative. After mixing with the filtered remains of the bleach reaction the two are combined. There is no precipitate from this — an indication that not everything is as it should be. But an overnight stay in the refrigerator results in the potassium chlorate crystals seen above.

Fiery testing (seen below) lets him know the experiment worked. From here the product can be used for things like making solid rocket engines.

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Stopping a hackerspace from rusting away

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.

Adult sized baking powder submarine

baking-powder-submarine

It really doesn’t matter what age you are, we’re sure you remember baking powder submarines. That’s because cereal manufacturers have been including them as prizes since the advent of injection molded plastic. Fill them with baking soda and take them in the bath with you. They gently dive and surface. The problem is that the cereal prizes were tiny. Now you can relive your childhood with an adult size version of your own making.

The submarine is basically a hunk of PVC with a conning tower to keep it upright and a chunk of hose into which the baking powder is placed. The idea is that the powdery acid and base that makes up the stuff reacts when hit with water. This gives off a bit of carbon dioxide, which makes the sub float to the surface until the bubble escapes and is replaced with water to again sink the ship. The difficult part is to find the right buoyancy (using wine bottle cork) so that the bubble is all it takes to oscillate between the surface and the watery depths.

Watch it go in the video after the break.

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On not getting metal fume fever with galvanized conduit

galv

You can find galvanized steel pipes at Home Depots and construction sites all around the world. These relatively thin-walled steel pipes would make for great structural members if it weren’t for the fact they were covered in a protective layer of zinc. This layer of galvanization lends itself to crappy welds and some terrible fumes, but badass, TV personality, and hacker extraordinaire [Hackett] shows us how to strip the galvanization off these pipes with chemicals available at any hardware store.

Since the galvanization on these pipes covers the inside and the outside, grinding the small layer of zinc off these pipes is difficult at best. To be sure he gets all the zinc off this pipe, [Hackett] decided to chemically strip the pipes with a cup full of muriatic acid.

The process is simple enough – fill a cup with acid, dunk the ends of the pipes, and clean everything up with baking soda. A great way to turn scrap pipe into a usable material, make a cool paper mache volcano, and avoid ‘ol galvie flu

[Read more...]

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