Webcam Turned Security Cam With Motion Detected Email Notifications

April 17, 2011 by Mike Szczys 27 Comments

[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.

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Hackaday Links: April 16, 2011

April 17, 2011 by Mike Szczys 8 Comments

Induction cook top provides power too

We’re familiar with induction cook tops but we never thought to power a microcontroller with one. [Thanks Hadez]

Ping-Pong Uranium

We’ve been big fans of the chain reaction demonstration using ping-pong balls and mouse traps ever since we saw [Mr. Wizard] do it back in the day. If you don’t know what we’re talking about, check out this demonstration that is analogous of a fission reaction. [Thanks nateL]

Phone tripod enclosure

If you’re interested in using your smart phone for some photography, [Mike] has a nice wood and elastic mount for an iPhone which you might try yourself.

Bicycle snow tires

Admittedly we’re a bit late on this one. But keep it in mind for next year: you can use some zip ties for added traction on your bike when it snows. [Thanks Rob]

Now you can BE mario

A little Kinect script lets this gentleman play Super Mario Bros. with his body. Now you can have all the fun that goes along with being a pixellated character stuck in a two-dimensional environment (plus, there are shrooms). [Thanks Das_Coach via Slashdot]

Oscilloscope Piano Tuning 101

April 17, 2011 by Jason Komp 10 Comments

[Todd Harrison] recently wrote in to tip us off on his submission to the Tektronix oscilloscope contest – using a scope to tune a piano. In his video he demonstrates how a Fast Fourier Transform can be used to determine the fundamental frequency of the note being played. This is a quick and easy way to determine if that key is in tune, and if not, how far off it is from the desired frequency and in which direction.

He goes on to explain that a scope can only be used as a starting reference point since “mathematically correct” tuning on a piano doesn’t sound right to the human ear. It turns out that when struck, the stretched wires in the piano behave less than ideally. In the case of a piano, the overtones (the other peaks shown on the scope higher in frequency than the fundamental) are actually slightly sharper (higher in frequency) than the expected harmonic whole-number multiple of the fundamental frequency. As a result, the frequency ranges of each octave must be “stretched” in order to accommodate this and sound correct when multiple notes are played together across octaves.

Typically, only the A4 key is actually tuned to its correct frequency of 440Hz and all of the other keys are manually tuned off of this baseline. The amount of necessary stretch applied to each octave increases as you get further away from this initial reference point in either direction and is unique to each and every individual instrument – thus there is no universal device capable of perfect tuning. Although [Todd] admits that he won’t attempt to tune the entire piano himself using this technique, he finds it a convenient way to keep the most heavily played center sections of the piano closer to true between professional tunings.

If you have any interesting or unique uses for your Techtronix scope, you can enter the contest here. Just don’t forget to tip us off too! Thanks [Todd]!

The Basics Of Building A Multitouch Table

April 16, 2011 by Mike Szczys 15 Comments

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.

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Pidato Box Adds Vibrato Effect To Digital Pianos

April 16, 2011 by Mike Nathan 9 Comments

piano_vibrato_box

[Joren] likes his digital piano, but it was missing one key component that he wanted to use: the ability to produce vibrato while playing. Vibrato can be done in several different ways on regular pianos, but it seemed as if there was not a lot of consideration given to the effect when designing digital pianos.

He enjoys playing all sorts of music, including solos from Franz Liszt which suggest using vibrato at times, so he decided to build himself a vibrato box. Constructed with a bit of assistance from the friendly folks at Hackerspace Ghent, his “Pidato” incorporates an Arduino and three-axis accelerometer to get the job done.

The Arduino is connected to both the MIDI output of the piano as well as to the accelerometer, which he has mounted on his wrist. While playing, all he needs to do is simply move his hand rapidly to produce the vibrato sound as you can see in the video below. The Arduino code filters out any other sorts of movements to ensure that he does not accidentally trigger the effect when it is not desired.

Check out the video below for a quick demonstration of the Pidato box.

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Pinewood Derby Cars Have Come A Long Way

April 16, 2011 by Jesse Congdon 20 Comments

Get your graphite and hike a wheel, [Aron Hoekstra] writes in to completely embarrass us with some excellent pinewood derby cars. In the pursuit of that extra something [Aron] consulted with his sons who came up with some cool ideas for cars, one Tron themed and the other basically a Wiimote with wheels! The official Pinewood derby rules say nothing about electronics, so as long as nothing helps the block-o-wood travel down the track faster, anything goes. This means you are free to load up whatever cool lights you want, but will have to earn your robotics merit badge some other way.

[Aron] Starts the builds by carving out the shape of the cars, each feature a hollowed out cavity underneath to accommodate the batteries and electronics. For the Tron Light Runner car, one continuous EL strip weaves in and out of the derby car’s body, and a single AAA battery runs the driver. [Aron] notes that it took around five feet of EL wire to cover the little car, which is two more than the driver is rated for. Fortunately the extra little bit of additional wire had little effect on its brightness.

The Wiimote car has detailed 3d buttons, a breadboard with a linear regulator, and PIC 16F628 driving blue LEDs. For the majority of the time the PIC simply runs a chase routine for the four LEDs, but [Aron] went through the trouble to program in the Wiimote’s start-up sequence!

Shown above the [Hokestra]’s work is my older brother’s pinewood derby car (top left) and my… potato rocket… thing… (top right) from many many years ago. I now seriously regret not considering LEDs! Although I think all that existed then was red, green and IR.

Check out videos of the [Hoekstra] bros’ cars after the jump!

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Creating NES Cartridge Clones From ROM Dumps

April 16, 2011 by Mike Nathan 25 Comments

Sometimes emulators just don’t cut it when you want to play a vintage game. Like it or not, some people enjoy the nostalgia of playing old games on the actual hardware for which it was designed.

[Callan] wrote in to share a method he has been using to make some of his own NES game cartridges from ROM dumps in order to play them on an honest to goodness NES console.

He starts out with a 190 in 1 game cartridge, where he found a neat Famicom game never released in the US. He decided he would patch the ROM he found on the multicart in order to have an English menu, and then create his very own cartridge from the image. He discusses how to identify which EPROM chips you will need in order to construct your cartridge, as well as some helpful ways of finding a donor cart that has a similar enough board to house your components.

[Callan] also provides a quick walkthrough of erasing and burning your new EPROM chips, before discussing some post-soldering troubleshooting steps you might need to take before your game will work properly.

While we can’t comment on the legality of these game clones, we still think it’s pretty awesome.

Be sure to check out his site for a far more in-depth discussion of the process if this is something that interests you.