Glimpses Of A 3D Volumetric Display

Custom displays are a lot of fun to look at, but this one is something we’d expect to see at a trade show and not on someone’s kitchen table. [Taha Bintahir] built a 3D volumetric display and is showing it off in the image above using a 3DS file of the Superman logo exported from Autodesk. In the video after the break you can see that the display is a transparent pyramid which allows a viewer to see the 3D object inside from any viewpoint around the display. Since first posting about it he has also added a Kinect to the mix, allowing a user to control the 3D object with body movements.

There’s basically no information about the display hardware on [Taha’s] post so we asked him about it. It works by first taking a 3D model and rendering it from four different camera angles. He’s using a custom designed prism for he display and the initial renderings are distorted to match that prism’s dimension. Those renderings are projected on the prism to give the illusion of a 3D object floating at its center.

We’re hoping to hear more details about how this was designed and what hardware is being used. We’ll post a follow-up if [Taha] shares more information.

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Aquarium Water Exchanger

If you want happy fish you’re going to need to do regular aquarium maintenance. Part of this is exchanging a portion of the tank’s water on a regular basis. [Bill Porter] came up with a water exchanger that means less manual labor, but makes the process just a bit more complicated.

So, what he would do before is fill a few buckets from the aquarium and dump them down the toilet. Then mix up a few buckets of salt water and add them back to the aquarium. This meant carrying several trips worth of heavy, dripping buckets through the house. What he has now is a gravity fed system into the orange bucket with a bilge pump to evacuate the old water from that bucket into the kitchen sink. The bilge can then be used to circulate water through the aquarium and the bucket, while filling with a hose from the kitchen sink and mixing in salt and chemicals. Less trips, no drips, but you’ve got to know what you’re doing with all of those valves.

We love seeing aquarium hacks like [Bill’s], or cooling the tank lights while heating the water, or just a fancy lighting setup in general. So if you’ve got some of your own, don’t forget to send in a tip about them.

Nokia Internet Key External Antenna

[Maurizio] was having some reception issues with his wireless internet and set out to add an external antenna to the USB dongle (translated). He had previously poked around inside of the Nokia internet key to find that the internal antenna was a flexible circuit substrate wrapped around a plastic box that made contact with main circuit board via a spring connector. This plastic frame is just right for mounting an SMA connector in just the right place for it to stick out the end of the case as seen in the picture above. It gives him better range, but since speed depends on how much traffic the wireless node is under, it’s not a guarantee that you’ll get a snappier connection after this hack.

Tri-rotor Helicopter With Full Autopilot

Quadcopters stand aside, here’s a three-rotor helicopter we think you’re going to love. The body is made out of plywood and carbon fiber rods, keeping it light enough to be easily lifted by just 3 motors while making sure the force doesn’t tear the aircraft apart. Three gyroscopes, two accelerometers, three magnetometers, and a GPS module are all used in conjunction for an autopilot system. There’s a lot of great pictures and videos but our favorite, embedded after the break, shows the tricopter writing messages in the sky using light and camera exposure tricks similar to this ground-based trike.

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Electronic Dice Has Option For 20 Or 100 Sides

[Bluewraith] built himself an electronic dice using a 555 timer and 4017 counter. This is a classic project and he enjoyed doing it but wondered about making a 20-sided dice. So he grabbed his Arduino and got to work. A switch on the final project selects between 20 or 100 sides. He used a MAX7219 to control the 7-segment displays, and a standalone AVR chip for the rest of it.

If you missed it back in October you should also look in on this 6-sided dice. It also uses an AVR running the Arduino bootloader but a mercury switch allows the player to shake the box in order to start a roll.

One last note, we made a conscious decision to use the word ‘Dice’ instead of the grammatically correct ‘Die’ which is its singular version. We think ‘Die’ can be a bit too confusing and we’re not the only ones.

Electrodes Turn Your Eyelids Into 3D Shutter Glasses

[Jonathan Post] has a way to watch 3D video without wearing shutter glasses but it might be kind of a hard product to break into the market. As you can see above, a pair of electrodes are stuck on a viewer’s eyelids, using electricity to alternately close each eye. The video after the break shows a demonstration of this technology. Obviously a camera can’t capture the image that the viewer sees, but this man describes a perfect 3D image. This reminds us of those ab exercisers that use electrodes to stimulate the muscles. Do you think a 3 hour epic would leave your eyelids tired and sore, eventually resulting and a steroid-esque muscle-ridden face?

Edit from [Caleb]: Judging from the comments, some people believe this to be an absolute impossibility. While we concur that this example is pretty silly (what’s powering those electrodes?), we invite you to watch [Daito Manabe]’s facial electrodes fun.

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$20 Fuel Injector Tester

[Dino] is an auto mechanic and needed a way to test out fuel injectors. Commercially available tools start well over $100 and go up from there, but he built his own for about $20.

The injectors have a coil in them that needs to be tested. His design calls for a series of 0.008 millisecond pulses to test the coil. He started by setting up a 555 timer to output a one second pulse. This signal is fed into a second 555 chip that outputs the 0.008 pulses and in turn actuates a MOSFET to switch the coil on and off. To use it [Dino] connects to a 12V bench supply and to the injector, using a single button to start the test. See him explain the setup in the video after the break.

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