Homemade Gravity Light Doesn’t Last Long but Proves the Concept!

gravity light

After being inspired by the Deciwatt Gravity light, [Steve Dufresne] decided he wanted to try making his own as a proof of concept.

The Gravity Light by Deciwatt is an innovative device designed for third world countries to help eliminate expensive lighting like kerosene lamps. It has a small weight on a pulley which can be lifted up in under 3 seconds. During its slow descent down the weight provides light for 25 minutes! It’s affordable, sustainable, and reliable. It’s also mechanically impressive, which is exactly why [Steve] decided to try making his own.

He’s using a single LED, a small DC motor, a few pieces of wood, an old bicycle wheel, some bicycle chain, and a few jugs of water. The water is connected to the chain which is looped over the smallest gear on the bike. The generator is then powered by a belt wrapping around the outside of the rim. This gives the motor enough speed to generate electricity for the LED. His current design only lasts for about 3 minutes, but he’s already working on the second iteration. Testing systems like this really give you an appreciation for the effort that must have gone into the real Gravity Light.

Stick around after the break to see it in action.

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Inkjet Transfers to Wood

Color Image on wood board

You can’t feed a piece of wood through a stock inkjet printer, and if you could it’s likely the nature of the material would result in less than optimal prints. But [Steve Ramsey] has a tutorial on inkjet transfers to wood over on his YouTube Channel which is a simple two-step method that produces great results. We really love quick tips like this. Steve explains the entire technique while creating an example project – all in under 2 minutes of video. We don’t want to get your hopes up though – this method will only work on porous absorbent surfaces like bare wood, not on PC boards. We’ve featured some great Inject PCB resist methods here in the past though.

The transfer technique is dead simple. [Steve] uses the backing from a used sheet of inkjet labels (the shiny part that normally gets thrown away). He runs the backing sheet through his inkjet printer. Since plastic coated backing sheet isn’t porous, the ink doesn’t soak in and dry. He then presses the still wet page onto a piece of wood. The wet ink is instantly absorbed into the wood. A lacquer clear coat seals the image in and really make the colors pop. We’d like to see how this method would work with other porous materials, like fabrics (though the ink probably wouldn’t survive the washing machine).

Click past the break for another example of [Steve's] work, and two videos featuring the technique.

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MountainBeest – A Theo Jansen Creature Comes Alive in My Garage

About a year ago, a member of my family sent me a video featuring [Theo Jansen's] StrandBeest, knowing that I was interested in all kinds of wacky and hackish inventions. My initial reaction was something to the effect of “wow that’s a neat device, but that guy is a little crazy.” For better or worse, the idea that this was an incredible invention turned over in my head for some time. Eventually, I decided that I needed to build one myself.  Apparently I’m a little crazy as well.

Theo’s original beest runs on a complicated linkage system powered by wind. He was nice enough to publish the linkage lengths or “eleven holy numbers,” as he calls him at the bottom of this page. He doesn’t, however, really explain how the connections on his PVC power transmission system work, so I was left to try to figure it out from his videos.  As you’ll see from build details and video to follow, this isn’t trivial. Keep reading past the jump to learn the adversity that I encountered, and how it was overcome in the end.

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Electron Beam Control In A Scanning Electron Microscope


A few years ago [Ben Krasnow] built a scanning electron microscope from a few parts he had sitting around. He’s done a few overviews of how he built his SEM, but now he’s put up a great video on how to control electrons, focus them into a point, and scan a sample.

The basic idea behind a scanning electron microscope is to shoot electrons down a tube, focus them into a point, and scan a conductive sample and detect the secondary electrons shot off the sample and display them on an oscilloscope. [Ben] is generating electrons with a small tungsten filament at the top of his electron ‘stack’. Being like charged, these electrons naturally fan out, so a good bit of electron optics are required to get a small point.

Focusing is done through a series of pinholes and electrostatic deflectors, much like you’d see in an old oscilloscope CRT. In the video, you can see [Ben] shooting electrons and displaying a Christmas tree graphic  onto a piece of phosphor-coated glass. He has a pretty big scanning area in his SEM, more than enough to look at a few chips, wafers, and whatever other crazy stuff is coming out of [Ben]‘s lab.

Video below, along with the three-year-old overview of the entire microscope.

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A Virtual Cane for the Visually Impaired


[Roman] has created an electronic cane for the visually impaired. Blind and visually impaired people have used canes and walking sticks for centuries. However, it wasn’t until the 1920′s and 1930′s that the white cane came to be synonymous with the blind. [Roman] is attempting to improve on the white cane design by bringing modern electronics to the table. With a mixture of hardware and clever software running on an Android smartphone, [Roman] has created a device that could help a blind person navigate.

The white cane has been replaced with a virtual cane, consisting of a 3D printed black cylinder. The cane is controlled by an ATmega328 running the Arduino bootloader and [Roman's] code. Peeking out from the end of the handle is a Maxbotix ultrasonic distance sensor. Distance information is reported to the user via a piezo buzzer and a vibration motor. An induction coil allows for charging without fumbling for tiny connectors. A Bluetooth module connects the virtual cane to the other half of the system, an Android phone.

[Roman's] Android app runs solely on voice prompts and speech syntheses. Navigation commands such as “Take me to <address>” use the phone’s GPS and Google Maps API to retrieve route information. [Roman's] app then speaks the directions for the user to follow. Help can be summoned by simply stating “Send <contact name> my current location.” In the event that the user drops their virtual cane, “Find my device” will send a Bluetooth command to the cane. Once the command is received, the cane will reveal its position by beeping and vibrating.

We’ve said it before, and we’ll say it again. Using technology to help disabled people is one of the best hacks we can think of. Hackaday alum [Caleb Kraft] has been doing just that with his work at The Controller Project. [Roman] is still actively improving his cane. He’s already won a gold medal at the Niagara Regional Science and Engineering Fair. He’s entered his project in several more science events, including the Canada Wide Science Fair and the Google Science Fair. Good luck [Roman]!

Play Peek-A-Boo with Blind Spot


You’re at a concert, and a car filled with balloons is in a glass box. As you approach the box, vertical blinds close to block the view directly in front of you. You move left, more blinds close to block your view. The blinds follow your every move, ensuring you can’t get a close up view of the car inside. You’ve just met Blind Spot, an interactive art installation by [Brendan Matkin].

Blind Spot was presented at Breakerhead, an incredible arts and engineering event which takes place every September in Calgary, Canada. Blind Spot consists of a car inside a large wooden box. Windows allow a view into the box, though there are 96 vertical blinds just behind the glass. The vertical blinds are individually controlled by hobby servos. The servos are wired to six serial servo controllers, all of which are controlled by an Arduino.

A PC serves as Blind Spot’s brain. For sensors, 6 wide-angle webcams connect to a standard Windows 7 machine. Running 6 webcams is not exactly a standard configuration. To handle this,  [Brendan] switched the webcams to friendly names in the windows registry. The webcam images are read by a Processing sketch. The sketch scans the images and determines which of the 96 blinds to close. The code for Blind Spot is available on github.

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Super Mario on a Human-Machine-Interface!

super mario

Getting Super Mario to work on your TI-83 calculator is almost a rite of passage for young geeks, so we really liked this project where [Chad Boughton] managed to get it running on a PLC’s HMI screen instead!

He’s using a Danfoss DP600LX microcontroller with an HMI display along with a CAN bus joystick. This kind of equipment is typically used to control hydraulic systems, as well as display sensor data — [Chad] was curious to see if he could do animation with it as well — it looks like he’s succeeded! The funny thing is we’ve seen those “joysticks” before and it’s cool to see them used for something like this — like [Chad] said, they’re normally used for actuating hydraulic and pneumatic cylinders.

Stick around after the break to see Mario eat some mushrooms.

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