Clever Reed Switch Catches Thief

magnetic_switch

When [Abhimanyu Kumar] noticed money going missing from his small bookshop, he decided to set up a little trap to catch the thief.

The problem was that the bookshop’s money was stored inside a cupboard in their house (back end of the shop), which meant that the culprit was likely one of their own employees. They already have a CCTV system installed in the actual store, and although he could simply add another camera in the house, [Abhimanyu] didn’t really want to do that.

He instead devised a simple security trap: dubbed the Jugaad Security System. In Hindi, Jugaad quite literally means “hack”. He added a small magnetic reed switch to the cupboard where the money is stored—well, was stored—which is then linked directly to an intervalometer. This then connects to an inconspicuous DSLR sitting on one of the work benches. He aimed the camera at the cupboard and, in case the lights are out when the system is tripped, set it to an extremely high ISO.

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If You Own a Camera You Need to Try Light Graffiti

orb-lake

Light graffiti orbs over a lake as seen here.

Do you have a camera that’s capable of controlling how long of an exposure it takes?  With this and any small light source, you can make a really awesome illuminated image like the one featured above.  Combine this with the hacking skills that you’ve hopefully learned from reading Hackaday, and the visual possibilities are endless.

Let’s look at the background of this entertaining light hacking technique, and how you can make images like this yourself!

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Sound blimp makes camera quieter and waterproof

soundBlimp

The D-SLR “crunch” sound can be pretty satisfying. Your camera has moving parts and those cell-phone amateurs can eat your shutter actuation. If you’re a professional photographer behind the scenes on a sound stage or at any film shoot, however, your mirror slapping around is loud enough to get you kicked off the set. [Dan Tábar] needed his D800 to keep it down, so he made his own sound blimp to suppress the noise. As an added bonus, it turns out the case is waterproof, too!

[Dan] got the idea from a fellow photographer who was using a prefab Jacobson blimp to snap pictures in sound-sensitive environments. Not wanting to spend $1000, he looked for a DIY alternative. This build uses a Pelican case to house the body of the camera and interchangeable extension tubes to cover lenses of various sizes. [Dan] took measurements and test-fit a paper cutout of his D800 before carving holes into the Pelican case with a Dremel tool. One side got a circular hole for the extension tubes, while the other received a rectangular cut for the camera’s LCD screen and a smaller circle for the viewfinder.

Lexan serves as a window for all of the open ends: LCD, viewfinder, and the lens. [Dan] snaps pictures with a wireless trigger, saving him the trouble of drilling another hole. You can hear the D800 before and after noise reduction in a video after the break, along with a second video of [Dan] trying out some underwater shots. If you’d rather take a trip back in time, there’s always the 3D printed pinhole camera from last week.

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Scratch-built gigapixel scanner

scratch-built-gigapixel-scanner

The presence of a camera in this image may be a bit confusing since we’re calling it a scanner. What’s actually going on is that macro-images this piece of art are being captured automatically. The multiple shots will later be assembled into one fascinatingly high-resolution image. The CNC scanner rig is [Charlie Romer's] summer project.

Unfortunately [Charlie] hasn’t yet collected all the information on the project into one place. After the break you’ll find more images, as well as a few demo videos. The best place to start is probably his proof-of-concept from this Spring. He shows a single-axis CNC mount for the camera. It takes an entire row of images. The assembled photo from that test is shown below. We believe the faint yellow dots in the macro part of the example are fingerprints purposefully left by the printer called printer stenography to help prevent forgery.

The larger rig uses movement on two axes. The idea is that the artwork will be perfectly positioned so that manual focus set at one point will work along all points in the capture routine. He’s using a lamp for a light source but we’re sure he will upgrade so something like a ring light as the project continues.

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Swapping the sensor in a DSLR

OLYMPUS DIGITAL CAMERA

To take a color image, modern digicams have something called a Bayer pattern – small red green and blue filters, one color for each pixel – that drastically reduce the resolution if all you’re doing is taking black and white pictures. [Lasse] is an astrophotographer, and doesn’t exactly need color pictures, so he decided to swap the color sensor in his camera with a monochrome CCD.

Most DSLRs have CCD sensors on strange surface mount packages or put everything on flex PCBs. [Lasse]‘s Olympus E-500, though, features an 8 Megapixel CCD on a ceramic DIP that is actually fairly easy to remove given the right tools and just a little bit of mechanical encouragement.

After putting in a new monochrome CCD, [Lasse] had a much more sensitive sensor in his camera, and processing the RAW files off the camera gives him a great improvement for his astrophotography.

This isn’t [Lasse]‘s first adventure in tearing apart DSLRs for astrophotography. Earlier, he uncovered the secrets of the Four Thirds lens format with a logic analyzer, making his Olympus camera a wonderful tool for looking into the heavens.

Bench equipment tip: Screenshot of old oscilloscopes

oscillocam-oscilloscope-camera-accessory

Here’s a quick tip on capturing the output of oscilloscopes that don’t have that native feature. [Paulo Renato] used a cookie tin as a camera cowl for capturing CRT oscilloscope screenshots.

We figure if you’ve got any kind of functioning oscilloscope you’re lucky. And although it’s nice to pull down the measurements to your PC on the newer models, the results [Paul] gets with this rig are still satisfactory. The plastic cookie box he used blocks out ambient light while holding the camera at a consistent focal length. He used some flat black spray paint to make sure the obnoxious yellow plastic didn’t interfere with the image, then drilled a hole which fits tightly around his camera lens.

You’ll need to monkey with the exposure settings to get the best image. But once you’ve got it dialed in it should be the same every time you want to take a picture of the screen.

Ghostly images captured only on camera

is that a logo

A while back our good buddy [Ch00f] built a QR code clock, unreadable to both humans and computers. A human couldn’t read the clock because of the digital nature of a QR code, and because the clock used persistence of vision in driving the LEDs, a digital camera can’t capture all the pixels in the QR code at the same time. It’s a highly useless but impressive art piece. Now, [Ch00f] is turning that build on its head. He created a rudimentary display that is invisible to the human eye, but easily detected with a digital camera.

This build exploits a basic property of CMOS digital cameras – the rolling shutter. Because it takes time to get pixels off a modern digital image sensor, each picture is actual a composite of many different strips, each taken slightly out of sequence. You can see this for yourself by taking a picture of something rotating very fast with your camera phone; a picture of an airplane propeller will make the blades appear curved, or look like [Dr. Seuss] has an aeronautical engineering degree.

To create his display, [Ch00f] found a few inexpensive fiber optic lights. By aligning a few of these into columns and lighting them up in a precise sequence, he can exploit the rolling shutter and make an image appear. To the human eye, it looks like a solid wall of illuminated fiber optics.

As for how practical this build is, [Ch00f] says not much. For cell phone cameras, you’d need to have a very, very short exposure time for this to work. The only way to do that is to make this display unbelievably bright, or just put it out in the sun. We can’t see that being practical for any potential use case, but we’d be more than happy to see a large-scale attempt at displaying images with this technique.