Nothing stinks up the house like a sink full of dirty dish. Well, a full trash can will do it to a greater extent, but that’s a project for another day. In what must be an overreaction to a perpetually full sink of dishes at his London Hackerspace, [Tom] built a web-connected dirty dish detector.

He calls it the Great OpenCV Wash-Up Detector. The system features a series of different signals to ‘remind’ forgetful geeks about cleaning up after themselves. The initial implementation uses a traffic signal to alert the room that there are dirty dished to be cleaned; illuminating the different colors to show how long the sink has been full. [Tom] also plans to add message bursts to the IRC room, and air horns when the situation gets dire.

As the name implies, this uses OpenCV to detect circles in the sink. A webcam has been mounted above it pointing straight down, providing a clear input image to detect plates, mugs, and the like. [Tom] even wrote some code that disables the system when the lights are turned off.

Of course, this may train offenders to leave the dishes on the counter where the detector can’t see them.

[David] sent in a nice project to demonstrate augmented reality with ARtoolkit and discuss the deep philosophical underpinnings of the meaning of nothingness. The good news is he was able to create a volume control button on a sheet of paper with a marker. The bad news is the philosophical treatment is a bit weak; [David] built something cool, so we’re able to let that slide for now.

This build was inspired by the Impromptu Sound Board made using a Kinect and a piece of paper. The idea behind the sound board is simple – draw some buttons on the paper, and use them to play short sound clips. [David] took this idea to make a small tutorial on augmented reality for Occam’s Razor.

The hardware is very simple – just a webcam, a piece of paper, and a marker. After [David] draws a large square on the paper, the code recognizes it as a volume control. Rotating the paper counterclockwise increases the volume, and clockwise turns the volume down. It’s a neat build to get into the foundations of augmented reality.

Check out the video demo of [David]‘s build after the break.

Most of you probably have a webcam sitting around somewhere, and after all the high voltage projects you’ve done using disposable cameras, we bet you have some camera lenses too. You could always do what [Butch] did and combine the lens from the camera with the webcam to do some up close inspection.

This seems like something we’ve seen several times, but we can’t find it in our archive. Such a simple and quick hack looks surprisingly effective in his shots. If you want to see the details, like where he tied into the webcam’s board to power an external LED, you’ll have to download the PDF.

As many of us do, [Steaky] serves as a kind of on-call help desk for his family. His father in law recently contacted him because his pan and tilt webcam died, and he wanted to see if it could be fixed. Never turning down a challenge, [Steaky] decided to give it a shot.

He ended up having to disassemble it since the camera was completely unresponsive, and what he found inside piqued his interest. The no-name camera sported an ARM microprocessor at its core, and it seems that some of its pins were damaged due to a poorly designed case. He figured resoldering the pins would do the trick, but that wasn’t the end of his adventures.

As he dug deeper into the device, he found that the camera essentially killed itself, reading and writing data to the wrong places due to the damaged pins on the processor. After plenty of searching around, he was able to find a somewhat compatible firmware image, though not everything worked properly.

His father in law was so impressed with his work that he asked for the camera back, even though [Steaky] hadn’t fully repaired it yet. While he bid the camera goodbye, we’re pretty sure he’d be more than happy to reclaim it for a few days if any of our readers had some additional insight or resources that might help him finish the job.

The guys from the House4Hack hackerspace in Johannesburg won the 2011 Google+ Hackathon with their Friggin’ Laser Turret. The build started off as a remote-controlled webcam that can be controlled by anyone in a Google+ hangout. On a whim, the team decided to add a laser to the build because lasers are awesome.

The inspiration for the build was to have a Google+ hangout available whenever someone is at the hackerspace. If a guest can’t grace the team with their physical presence, at least they can be there virtually. The camera is controlled by an Arduino running a bog-standard servo library implementation. The Arduino is connected to a laptop over a serial connection and is able to move left and right. To spice things up a little, the team added a 25mA laser diode to the build controlled from a digital output on the Arduino.

For winning the Jo’burg Google+ Hackathon, the guys scored themselves a Samsung Galaxy S II phone. Not a bad prize for building something cool. Check out the demo of the friggin’ laser turret after the break.

[Chris] recently got himself a nice web cam for documenting his Makerbot builds, and much like [Dino], he was looking for a way to get a bird’s-eye view of the action while keeping the camera nice and steady. While [Dino] ventured off to the hardware store, [Chris] tried a few different options that included tape, before heading off to Ikea to see what he could find.

$9 and a few Swedish meatballs later, he was on his way home with a “TERTIAL Work Lamp” that can be mounted on virtually any desk-like surface. He had to remove most of the web cam’s useless mounting hardware, doing the same with the lamp’s light fixture. He put together a small bracket in Google Sketchup, which he then printed out using his Makerbot.

It fit perfectly, and now he can get steady video of his Makerbot prints every single time.

[Sean] happened to have an extra Android phone sitting around and wanted to see what type of home automation he could use it for. One simple hardware modification, and some apps from the Android Market let him monitor and control his garage door remotely.

The hardware modification is a hack we’ve already looked at. The BTmate uses a Bluetooth headset with an added transistor to short the connections on your garage door opener. The only issue is that you need to be within range for the Bluetooth to work. [Sean] adds a layer of abstraction by using two Android phones. One is permanently mounted in the garage and handles the Bluetooth connectivity, while the other uses VNC to tunnel in anywhere he has an Internet connection.

But why stop there? He knew that this one feature was overkill, and added a second which the phone was perfect for. Since it has its own camera, he used the tinyCam app to create a webcam server. This even allows him to turn the LED on and off for a better view in dim light conditions. See [Sean's] demonstration after the break.

Overkill? Maybe, but if you’ve got a phone with a broken LCD, this might be just the thing to give it a new purpose.

[Randall Munroe], the guy behind our favorite web comic xkcd, gave us yet another great project idea that falls on the heels of securing our valuables and silencing loud car stereos. The xkcd forum has been talking about how to implement this, and we’d like to hear what Hack A Day readers think about this idea.

The project isn’t much different from 3D photography. [Carl Pisaturo] has done a lot of art and experimentation based on this idea that basically amounted to largish binoculars. A poster on the xkcd forum has already built this using mirrors, but we’re wondering how much the parallax can be increased with this method. Two cameras and a smart phone would also allow automatic pan and tilt that corresponds to head movement.

We’re not quite sure if this idea can be applied to astronomy. The angular resolution of the human eye is around one arc minute, every star except for the Sun has an annual parallax less than one arc second. If anyone wants to try this out with a longer baseline (From Earth to Pluto for example), we would suggest simulating this in Stellarium. Seeing the moon as a sphere would be possible with a few hundred miles between cameras, though.

Tell us how you would build this in the comments, and be sure to send in your write-up if you manage to build it. We’ll put it up right away.

Thanks to [Theon144] for sending this in.

EDIT: Because the comments are actually bearing fruit, check out the thread on the Hack A Day forums for this post: link.

[Kyle McDonald] is up to a bit of no-good with a little piece of software he wrote. He’s been installing it on public computers all over New York City. It uses the webcam found in pretty much every new computer out there to detect when a face is in frame, then takes a picture and uploads it to the Internet.

We’ve embedded a video after the break that describes the process. From [Kyle's] comments about the video it seems that he asked a security guard at the Apple store if it was okay to take pictures and he encouraged it. We guess it could be worse, if this were a key logger you’d be sorry for checking your email (or, god forbid, banking) on a public machine. Instead of being malicious, [Kyle] took a string of the images, adjusted them so that the faces were all aligned and the same size, and then rolled them into the latter half of his video.

[Stephen Albers] offers his avian friends a lot of extras with this electronically monitored bird house. This will not only give you a look at what’s going on inside, but provide a source for several other bits of data as well.

First off, a camera has been mounted to the underside of the roof. This looks down on the nesting area and features night vision so that you can peek in any time day or night. He used a WiFi webcam that operates separately from the other electronics.

With the remainder of the setup he is able to harvest temperature and humidity data inside, temperature outside, force on the bottom of the house (although this turned out to be less useful than anticipated), and a in-and-out count for the doorway provided by an IR transmitter/receiver pair.

This offers quite a bit more than the last bird house project we saw. That one also left a lot to be desired as far as protecting the electronics. [Stephen] didn’t skip on that kind of protection. Most of the electronics are housed in an acrylic chamber in the base of the house. The sensors find themselves nestled in plastic enclosures, although some work needs to be done to ensure that the temperature and humidity sensors will still function correctly with this setup.

[Mathieu] was on holiday in China and picked up some fun toys while perusing the numerous electronics markets there. The most interesting things he discovered were a pair of RGB LED matrices. They came in two different flavors, one made for indoor and one for outdoor displays, sporting a 64×32 and 32×16 resolution, respectively.

If you’ve read his blog before you know he is a big fan of LED matrices, so it’s only natural that bought a whole bunch of them and started experimenting once he got home. Using the same Amtel FPSLIC LED matrix control board he showed off in this previous hack, he was able to get the LED matrices up and running in no time. He adapted his webcam project to utilize the new panels, and he added a whole new feature as well. Via MatLab, he can now display any sort of animated gif on the panels, as you can see in the video below. The panels look great, and if we had a few of these around, there’s no doubt we would probably play this video on infinite repeat.

He says that the despite their somewhat questionable origins, the panels are of top notch quality, and he is willing to organize some sort of group buy if others are interested.

[Sean] used his old webcam to assemble a closed circuit television feed for his home. He already had a server up and running, so this was just a matter of connecting a camera and setting up the software. He wasn’t satisfied by only having a live feed, so he decided to add a few more features to the system.

He started off by hanging a webcam near the front of his house. He mentions that he’s not sure this will last long exposed to the elements, but we think it’d be dead simple to build an enclosure with a resealable container and a nice piece of acrylic as a windows. But we digress…

The camera connects via USB to the server living in the garage. [Sean's] setup uses Yawcam to create a live feed that can be access from the Internet. The software also includes motion detection capabilities. Since he wanted to have push notifications when there was action within the camera’s view he also set up Growl alert him via his iOS devices. You can see [Sean] demonstrate his completed CCTV system in the video below the fold.

Here is a bare-bones multitouch table setup. We looked in on [Seth Sandler's] multitouch work a few years ago when he completed the MTmini build. He’s scaling up the size a bit with the MTbiggie, and showing you how easy it is to put together. The demo rig seen above is just a couple of chairs, a sheet of acrylic, a mirror, a projector, a computer, and a diy infrared webcam.

The rig uses ambient infrared light to detect the outlines of your fingers when they touch the acrylic surface. A webcam with an exposed camera film filter feeds an image of the infrared light received below the surface to the computer. The incoming video is processed using Community Core Vision, where each individual point is isolated and mapped. Once the data is available the sky’s the limit on what you can develop. [Seth's] demo packages include a mouse driver, some physics applications, an Angry Birds implementation, and a few others. See for yourself in the video after the break.

[Erik] was looking for a sturdy robotics platform and was initially considering the iRobot Create, until he found that he could score a Roomba Discovery series for a fraction of the price. The Discovery includes a battery, which is missing from the iCreate, though it also has all of the standard vacuum bits included as well.

He immediately removed all of the vacuum parts once he got his hands on the Roomba, and began adding the support structure to house the rest of his robot’s components. The robot is controlled via a small laptop which sits on top of the Roomba’s base, and features a panning and telescoping webcam to provide feedback to the operator.

The robot has been under construction for a little over a year now, and has had a few upgrades over that time. The original laptop was swapped out for a newer dual-core model, and the webcam was upgraded to a model featuring motion tracking. The whole thing has been skinned in thin sheet metal for a sleek look, and he has added a servo-driven arm as well.

The project is not quite complete, and he hasn’t really stated what he plans on using the robot for, but it looks good so far – we can’t wait to see it when it’s finished.

[Dusjagr] has another take on building a laser projection microscope. Last year we saw a laser-based microscope that shined the beam of light through a water droplet which contained the subject to be magnified. The droplet bent the focused beam of light and projected the magnified contents onto a screen. Now that’s pretty neat and [Dusjagr] has used that method himself. But most traditional microscopes use glass slides to contain the subject and this new version now makes that possible.

A bit of experimentation led [Dusjagr] to the discovery that a lens re-purposed from a webcam can achieve similar focus results as a water droplet. The video after the break shows the apparatus seen above in action. The laser shines through the lens, then through a slide that contains a water sample from a nearby pond. The image is clear, albeit completely bathed in green.

For us the most interesting part of [Dusjagr's] writeup is his discussion of the limits of laser amplification based on the wavelength of light the diode puts out.