ReSCan — Automated Resistor Identification!

February 16, 2014 by James Hobson 59 Comments

Need a quick and easy way to sort through a few hundred random resistors? You could do them one at a time by reading the color codes yourself… or you could get a machine to do it for you!

When [Robert] was faced with a pile of unsorted resistors he quickly decided he did not have the patience to sort them manually. So, he started by writing an Android app using OpenCV to detect and identify resistor color codes. The problem is, most phones have trouble focusing at short distances — and since resistors are so small, holding the phone farther back results in color rings only being a few pixels wide — not the greatest for image recognition!

So, he started again on his computer, using a cheap LED-lit webcam instead. He wrote the app in java so he could re-use parts of the code from the Android app. It seems to work pretty well — check it out in the following video! This would be perfect to pair up with your illuminated storage bin hack.

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Using A Computer To Read Braille

February 9, 2014 by Brian Benchoff 6 Comments

braille

[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

January 27, 2014 by James Hobson 9 Comments

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

January 23, 2014 by Marsh 16 Comments

[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

January 8, 2014 by James Hobson 58 Comments

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

December 16, 2013 by Kristina Panos 1 Comment

arduinoPhotoRig

[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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OpenMV: The Camera For Your Next Project

December 8, 2013 by Brian Benchoff 12 Comments

Last month we saw [Ibrahim] tackle the lack of cheap, high speed, high resolution serial cameras with full force. He designed a serial camera based on the STM32F4 microcontroller that’s the perfect solution to anyone wanting to add visual processing or machine vision to a project. It’s cheap, too: instead of the $100 or so you’d spend on a high-end serial camera, [Ibrahim]’s version only has about $15 in parts.

Now he’s back at it again, with 25 FPS face detection, 30 FPS color detection, a new board with a micro SD socket, and support for USB OTG full speed. [Ibrahim] has been hard at work deep in the bowels of the STM32F4 micro, playing around with the core coupled memory. This allows for some very fast image processing, combined with the micro running at 168 MHz makes for very fast face and color detection.

As for a few benchmarks for this camera, the maximum resolution is 1280×1024, and at 88×72 resolution this little board can output at 60 FPS. Of course everything is limited by the speed of the serial connection, but there’s a lot of potential in this small serial camera.

No word on how much this board will cost, but [Ibrahim] may be putting a few boards up on Tindie shortly. Here’s to hoping he’ll send us an email telling us when his store is open.