A solar clock that isn’t a sundial

Hack a Day’s very own [Jack Buffington] is throwing his hat into the ring for the Buildlounge laser cutter giveaway with his solar clock that isn’t a sundial.

The theory behind [Jack]‘s clock is pretty simple. The light from the sun will be captured by a camera obscura/pinhole camera. The sun’s rays shine on dozens of optical fibers that lead indoors and up to the clock. These glass fibers go to pinholes in the face of the clock which light up, showing the time.

[Jack] already cut out the face of the clock on his (awesome) home-made CNC router. He hasn’t gotten around to cutting out the mechanics of the clock face so the clock can be adjusted throughout the year. We’re okay with that, because we’re really not ready to see [Jack] fiddle with his gnomon. At least before [Jack] gets his hand on the Buildlounge laser.

The next major hurdle of the build is the solar collector that collects light into different optical fibers. That’s going to involve a lot of math using the equatorial coordinate system. Help is available, though.

Check out [Jack] cutting the clock face on his router after the break.

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Micromouse wins 2011 maze race in under 4 seconds

It’s off to the races once again with the Micomouse maze solving contest at the 2011 RoboGames. This is a picture of the winner, a bot called Min7 (main page) which was built by [Ng Beng Kiat]. Using four phototransistors and a flash sensor it managed to first map the contest maze, then speed run it in under four seconds. See both runs in videos after the break. He’s certainly got a leg up on the bots we saw last year. Min7 beats them both in time, and overall control during the speed run.

[Ng] mentions that this year is the first time he’s built a micromouse with four wheels instead of two. There’s a gyro on board which aids navigation by feeding the orientation data to the STM32 chip which controls the device. We took a moment to page through his past designs. It’s remarkable how they’ve evolved through the years. [Read more...]

Eight-dollar airplane for really bad pilots

Have a habit of hitting the bottle before getting into the cockpit? Find that your mind wanders mid-flight? Lack the hand-eye coordination to keep that RC creation of yours in the air? Worry not, you can build this flyer and crash it with impunity.

[HammyDude] built the RC aircraft out of laminated foam board. He’s had it for years and it’s survived multiple crashes. You can see the one real injury suffered, a snapped fuselage at the leading edge of the wings. He repaired it with popsicle sticks and it’s been going strong ever since.

In addition to the wooden reinforcements he’s covered the fuselage with fibrous packing tape (you know, the stuff with the strings running in it). There’s also a carbon fiber tube at the leading edge of each wing. It’s light, strong, and robust (with the exception of the propeller of which he’s broken about 10).

Check out the video after the break for an explanation of the aircraft, list of materials, and HD images of the patterns you need to make them yourself. The only thing you won’t see is flight footage.

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Printable solar cells that can be folded up when not in use

Here’s a photovoltaic cell that can be printed onto paper. The manufacturing technique is almost as simple as using an inkjet printer. The secret is in the ink itself. It takes five layers deposited on the paper in a vacuum chamber. But that’s a heck of a lot easier than current solar cell fabrication practices. In fact, is sounds like the printing process is very similar to how potato chip bags are made. This is significant, because it could mean a fast track to mass production for the technology.

It isn’t just the easy printing process that excites us. Check out the video after the break where a test cell is placed on top of a light source while being monitored by a multimeter. It’s been folded like a fan and you can see a researcher sinch up the cell into a small form for storage. It’s a little counter-intuitive; for instance, you wouldn’t want to make a window shade out of it because it would have to be down during the day to get power. Be we think there’s got to be some great use for these foldable properties. [Read more...]

Cheap DIY tilt switches are great in a pinch


[fjordcarver] was looking for some mercury-free tilt switches that wouldn’t break the bank and that were easy to build. He also wanted something cheap, so instead of buying some tilt switches he devised his own that fit all of the criteria he set out. Now, these switches are not your typical fare, and they’re not small either. They are however, cheap, effective, and easy to manipulate/repair.

He picked up a package of metallic craft beads at the store and emptied out two bottles, saving one set of beads that happened to be conductive, i.e. not coated with paint or coloring. The beads were split between two jars, which were then sealed with corks that had a pair of straightened paperclips inserted through them. The bottles were oriented facing away from one another, then attached together with a piece of house wire. One of the leads from each jar was attached to this common wire, while the others were extended with hook up wire for use in the circuit he was building. Pictures definitely explain the mechanism far better than words can, so be sure to check out his tutorial to get a better look at them.

While they might look a bit rough, he says they work great, so give them a try if you have the need.

Children’s light up toy is an easy hand-made gift


While this year’s Christmas lists are dominated by electronic gadgets and other mass-produced toys, it wasn’t always like that. We’re not trying to sound like the old man yelling at the neighborhood kids to get off his lawn, but many of today’s gifts lack the personal touch found in old, hand-made toys.

[henlij’s] son is a budding electronics geek who loves playing with switches and lights, so he was inspired to build him a fun toy to pass the time. He constructed a simple box full of lights and switches that his son could toggle on and off to his heart’s content.

While there’s not a ton going on inside the box, we think that the idea is fantastic. With just a few dollars worth of simple components, anyone who knows their way around a soldering station can build something that will keep a child fascinated for hours.

There’s no reason to stop at buttons and lights either. If we were to build one, we would swap the bulbs out for LEDs, then add a wide variety of switches and dials along with speakers and any other components we could get our hands on.

The options are pretty limitless, so if you happen to know a child that gets a kick out of playing with buttons and switches, why not make him or her something special this year, much like [henlij] did for his son?