Solar oven built to last

The problem with most solar ovens is that they’re flimsy builds that will stand up to only a handful of uses. But this one stands apart from that stereotype. It’s big, sturdy, and used a lot of math to efficiently gather the sun’s energy when cooking food.

This is the third version of the build and each has included many improvements. The obvious change here is a move from aluminum reflectors to actual mirror reflectors. These attach at a carefully calculated angle to get the most power from the rays they are redirecting. The orange mounting brackets for the mirrors also serve as a storage area for transport. The rectangular reflectors fit perfectly between them (stacked on top of the tempered glass that makes up the transparent side of the cooking chamber).

The body of the oven doesn’t track the sun and one of the future improvements mentions adding tilt functionality to the base. We’d suggest taking a look at some of the solar tracking setups used for PV arrays.

[Thanks John]

Hackaday Links: July 1, 2012

Opening really old lock boxes

[Barry Wels] is a locksmith. One day, he got a call from a museum that had a few 17th century strong boxes that needed to be opened. After a little probing with an endoscope, he decided they could be picked with a little bit of spring steel. So, what’s in the box? [Barry] is going to send in an update in a month or two.

An awesome Geordi La Forge VISOR. But don’t take my word for it.

[DrewSmith007] made a replica of Geordi’s VISOR from Star Trek: The Next Generation. Bonus: it’s autographed by Levar Burton.

Free mirrors for your laser cutter

If you have a laser cutter, your mirrors will get damaged, and they’re very expensive to replace. [Phil] sent in a neat tip: make your own mirrors from hard drive platters.

A proper M.U.L.E. remake

Combine Settlers of Catan with M.U.L.E.. That’s what this Kickstarter is trying to do, and it sounds freakin’ awesome.

This game is so cool

A few months ago, I mapped the surface of a video game moon. Since then, Kerbal Space Program had a huge update with a brand new moon. Over on Reddit, [InsanityCore] started mapping this new moon, so I rendered it. Go give [InsanityCore] some karma. He did all the hard work.

Digital gaming table made with no smoke, just a mirror

The concept of having a digital gaming table got stuck in [RobotGuy's] mind over the weekend and he managed to whip this up in no time using materials on hand. He already had a ceiling-mounted projector which just happens to reside immediately above the space occupied by his coffee table. By swapping that piece of furniture out for a white Ikea table, and adding a mirror to the projector he now has the virtual gaming surface he was looking for. The mirror mount is nothing more than a desk lamp that includes a spring clamp and flexible neck. He hot glued the piece of mirror to this, and attached it to the projector’s ceiling anchor. Since rear-projection screens are common, all digital projectors have the ability to mirror and rotate the image being displayed so that it appears on the table in the correct orientation.

We love the look, but this is really only one portion of a digital gaming project. We think the table needs some interactivity. We often see this done using infrared light processed by a webcam. That multi-touch option is not going to work with a standard table since the camera needs to be on the opposite side of a translucent surface. But if you don’t mind using a stylus this IR whiteboard technique would work.

Cloud Mirror adds Internet to your morning ritual

This mirror has a large monitor behind it which can be operated using hand gestures. It’s the result of a team effort from [Daniel Burnham], [Anuj Patel], and [Sam Bell] to build a web-enabled mirror for their ECE 4180 class at the Georgia Institute of Technology.

So far they’ve implemented four widget for the system. You can see the icons which activate each in the column to the right of the mirror. From top to bottom they are Calendar, News, Traffic, and Weather. The video after the break shows the gestures used to control the display. First select the widget by holding your hand over the appropriate icon. Next, bring that widget to the main display area by swiping from right to left along the top of the mirror.

Hardware details are shared more freely in their presentation slides (PDF). A sonar distance sensor activated the device when a user is close enough to the screen. Seven IR reflectance sensors detect a hand placed in front of them. We like this input method, as it keep the ‘display’ area finger-print free. But we wonder if the IR sensors could be placed behind the glass instead of beside it?

[Read more...]

Laser light show comes to life from the junk bin

In a project that only spanned about three weeks [Lars] built this laser light show projector using parts scavenged from his junk bin. We’ve seen the concept many times before, all you need is a laser source and two mirrors mounted on a spinning bases. The laser diode for this project was pulled from a recordable DVD player. That beam passes through the optics from a laser printer to give it the focus necessary to get a good projected image.

[Lars] played around with the mirror angles until he achieved just the right look. The first mirror is mounted about 4 degrees from being flat with its motorized base; the second is off by about 6 degrees. This introduces slight oscillation in the beam direction when the motors are spinning. By adjusting the speed of each motor you get different patterns. Adjustments are happening completely at random thanks to the BasicStamp2 microcontroller which hadn’t been used in years. Fifteen lines of code were all it took.

Want a laser that’s not controlled at random? Check out this addressable galvanometer-based show.

Milling curves into mirrors and glass

[Ben Krasnow] is working on  a project that uses an extremely expensive specialty mirror. He needed to cut curves into it, taking care not to chip or shatter the material. He’s found a reliable way of doing this with a CNC mill and is sharing his methods.

The material he’s working with is a cold mirror; it reflects visible light while allowing infrared light to pass through. He had to custom order it, breakage is not acceptable. [Ben] explains that the biggest risk when milling glass is the clamping method used. He built his own jig and uses shims, rather than clamps, to secure the material along the X and Y axes. It is held down on the Z axis using a bar of acrylic spanning from one side to the other with rubber feet on the bottom.

A diamond burr cutter does the work, spinning at 3000 RPM. [Ben] recommends moving the head at the slowest rate possible in order to give the cutter time to do its work. And of course the material needs to be kept cool by pumping cutting fluid across it. As he shows in the video after the break, what you get is a piece of glass that comes out with clean and smooth edges.

In case we’ve sparked your curiosity, this mirror will be used during an MRI scan. The patient looks at a monitor reflected in the mirror at a 45 degree angle. At the same time, an infrared camera records the patient from the other side of the mirror to monitor where they are looking.

[Read more...]

Analog projection clock so simple you should have thought of it

The image you see above is the result of a simple analog projection clock. It shows the time on the ceiling. We have one in our bedroom but it’s a red digital display which we don’t think is nearly as fun as this clever hack. Grab a cheap analog clock, a mirror, and a white LED and you can build your own.

The mirror is going to reflect light from the LED onto a ceiling or other surface. It acts as the clock face. The tick marks for each hour were made by scratching the reflective material (often called the silvering) from the back of the mirror. A hole is drilled at the center of the class and the analog clock is mounted with its hands on the business side. The one problem with this setup is that since the light is being reflected, the clock will appear to run backwards. Not a problem, if you just reverse the polarity of the coil which moves the clockwork the projection will move in the expected clockwise direction.

[via Make]