Using A Computer To Read Braille

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[Matthiew] needed to create a system that would allow a computer to read braille. An electromechanical system would be annoying to develop and would require many hardware iterations as the system [Matthew] is developing evolves. Instead, he came up with a much better solution using a webcam and OpenCV that still gets 100% accuracy.

Instead of using a camera to look for raised or lowered pins in this mechanical braille display, [Matthiew] is using OpenCV to detect the shadows. This requires calibrating the camera to the correct angle, or in OpenCV terms, pose.

After looking at the OpenCV tutorials, [Matthiew] found a demo that undistorts an image of a chess board. Using this same technique, he used fiducials from the ARTag project to correctly calibrate an image of his mechanical braille pins.

As for why [Matthiew] went through all the trouble to get a computer to read braille – something that doesn’t make a whole lot of sense if you think about it – he’s building a braille eBook reader, something that just screams awesome mechanical design. We’d be interested in seeing some more info on that project as well.

Yet Another DIY Camera Slider

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Professional camera gear is expensive, which is probably why there is such a huge DIY field for camera equipment. Here’s another great DIY camera slider that you can build for cheap.

Similar to other rigs we’ve seen, the heart of this design makes use of skateboard wheels — they’re cheap, have good bearings, and are easy to mount. He’s created a dolly for them using a T-strap bracket, which is used for wood framing — the wheels mount directly to it without any modification.

What we think is unique about this build are the rails [Shootr] decided to use. They’re U-Post fence posts — strong, rigid, and probably one of the cheapest forms of processed metal you can buy. To hold them together, he’s using a threaded rod with two pieces of 1/2″ square steel tubing, bracing the fence posts. This wedges the dolly in between them with just enough slack to slide smoothly back and forth.

The other method of making a camera slider like this is using tubular rails, which also allows you to add a curve in your camera track. And if you’re looking for a precise, 2-axis camera dolly… you should check out this one!

AVR Barn Door Tracker for Astrophotography

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[ZigZagJoe's] first foray into astrophotography is this impressive AVR barn door tracker, which steps up his night sky photo game without emptying his bank account. If you’ve never heard of astrophotography, you should skim over its Wikipedia page and/or the subreddit. The idea is to capture images otherwise undetectable by the human eye through longer exposures. Unfortunately, the big ball of rock we all inhabit has a tendency to rotate, which means you need to move the camera to keep the night sky framed up.

Most trackers require precision parts and fabrication, which was out of [ZigZagJoe's] grasp. Instead, he found a solution with the Cloudbait Observatory model, which as best as we can tell looks vaguely similar to the tracker we featured last year. Unlike last year’s build—which uses an ATmega32u4 breakout board— [ZigZagJoe's] tracker uses an ATTiny85 for the brains, running a pre-configured table that determines step rate against time.

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Clever Reed Switch Catches Thief

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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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Tricked-out Arduino-controlled Time-Lapse is More Than Just a Timer

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[Hlesliebole] wanted a finer degree of remote control over his time-lapse shots, so he decided to build an Arduino-driven infrared shutter. He ended up creating this killer Arduino-controlled photography rig that does a whole lot more.

This hack was built for [Hlesliebole]‘s Nikon D3100, but he says it should work with any DSLR and remote shutter. This initial build uses an LED as a stand-in for the remote shutter that he ordered.  He intends to update the post once it arrives and he integrates it.

[Hlesliebole] wired a 7-segment display to show the current time delay between photos. This can be set on the fly with a potentiometer, so there’s no need to stop and reprogram the Arduino. And while you’re grabbing a beer and watching the sun slowly sink, the rig can better capture that sunset because of a photoresistor. It detects the ambient light level and minimizes the number of throwaway dark shots.

If that weren’t enough, he’s built servo functionality into the code to support remote control over the camera’s physical position, allowing for panning or rotation over a scene. [Hlesliebole] doesn’t go into detail, but he assures us that there are many tutorials out there.  If you think you’re man enough, you could always work in this outstanding versatile motion dolly hack.

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If You Own a Camera You Need to Try Light Graffiti

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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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39 Raspberry Pi 3D Scanner

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[Richard] just posted an Instructable on his ridiculously cool 39 Pi 3D Scanner! That’s right. 39 individual Raspberry Pies with camera modules.

But why? Well, [Richard] loves 3D printing, Arduinos, Raspberry pies, and his kids. He wanted to make some 3D models of his kids (because pictures are so last century), so he started looking into 3D scanners. Unfortunately almost all designs he found require the subject to sit still for a while — something his 2-year old is not a fan of. So he started pondering a way to take all the pictures in one go, to give him the ability to generate 3D models on the fly — without the wait. 

He originally looked at buying 39 cheap digital cameras, but didn’t want to have all the images on separate SD cards, as it would be rather tedious to extract all the images. Using the Raspberries on the other hand, he can grab them all off a network. So he set off to build a very awesome (and somewhat expensive) life-size 3D scanning booth. Full details are available on his blog at www.pi3dscan.com

Stick around after the break to see it in action at Maker Faire Groningen 2013!

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