Turning a webcam into a spectrometer

If you want to find out what something is made out of, you’ll probably be using a spectrometer. These devices allow scientists to determine what something is made of by shining light through an object and recording what colors are absorbed. Professional spectrometers cost many thousands of dollars, but you can build your own using a simple USB web cam, an old DVD-R, and a VHS cassette case.

In this tutorial of Public Labs’ DIY video spectrometer, [Jeffery] takes us through the process of building a spectrometer. After cutting a small bit of plastic from a DVD-R and mounting it on the lens of a web cam, [Jeff] puts the webcam in a VHS case and shines a light through a small slit. The result is a rainbow pattern captured by the webcam, and by putting different translucent materials in front of the light source, the spectrum slightly changes.

Of course a DIY spectrometer is nearly useless without a library of materials and their associated spectra. [Jeffery] is working on this as well with a wiki-style app called Spectral Workbench.

There’s a video tutorial for making your own DIY spectrometer available after the break. It seems like an easy build, if you can find the requisite VHS cassette case in your basement and/or attic.

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Catch neighborhood speeders with your webcam

[John] is keeping the neighborhood safe by keeping an eye out for speeders. Well, he’s really keeping a webcam out for speeders. His technique doesn’t use radar or lasers. He’s processing webcam frames in Python to calculate speed.

It comes down to some basic image manipulation. He firsts gathers the images necessary to make the calculations by using a motion-detecting webcam program called YawCam. The images are analyzed to establish which parts have changed between frames; this gets rid of all the stationary objects. Now the frames can be compared to establish the distance in pixels. By calibrating the shot through measurements of the target area, this data can be directly converted into actual distance. It is then compared with the timestamps from each frame to arrive at speed. This can be used for vehicles on the street like we see above, or more whimsical measurements like pet turtle progress.

Monitor your heartbeat with a webcam and a flashlight

After seeing some heart rate monitor apps for Android which use the camera and flashlight features of the phones, [Tyson] took on the challenge of coding this for himself. But he’s not using a smart phone, instead he grabbed a headlamp and webcam for his heat rate monitor.

To start out he recorded a test video with his smart phone to see what it looks like to cover both the flash LED and camera module with his thumb. The picture is mainly pink, but there’s quite obviously a color gradient that pulses with each gush of blood through his skin. The next task was to write some filtering software that could make use of this type of image coming from a webcam. He used C# to write a GUI which shows the live feed, as well as a scrolling graph of the processed data. He took several tries at it, we’ve embedded one of the earlier efforts after the break.

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Getting a textured 3D scan from just a webcam

Here’s an oldie but a goodie that passed us up the first time it went around the Internet. [Qi Pan], (former) PhD student at Cambridge, made a 3D modeling program using only a simple webcam. Not only does this make very fast work of building 3D models, the real texture is also rendered on the virtual object.

The project is called ProFORMA, and to get some idea of exactly how fast it is, the model of a church seen above was captured and rendered in a little over a minute. To get the incredible speed of ProFORMA, [Qi] had his webcam take a series of keyframes. When the model is rotated about 10°, another keyframe is taken and the corners are triangulated with some very fancy math.

Even though [Qi]‘s project is from 2009, it seems like it would be better than the ReconstructMe, the Kinect-able 3D scanning we saw a while ago. There’s a great video of [Qi] modeling a papercraft church after the break, but check out the actual paper for a better idea of how ProFORMA works.

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Land ROV is Internet connected and packed full of stuff

[Blair Kelly] has always been interesting in the concept of Remote Operated Vehicles. As soon as he got his hands on an Arduino he began his endeavor to turn an RC vehicle into a land-based ROV. What he’s done so far is incredible.

Here he’s showing off features of the build using a PS3 controller. But it can also take commands from an Xbox 360 controller or an arcade-style steering wheel. We like the latter the best, which is shown off at about six and a half minutes into the video (embedded after the break). Since there’s a webcam on board, this ends up being a virtual cockpit for the pint-sized car. But it gets better. That webcam is mounted on a servo motor, and [Blair] included controls that pan the camera. This lets the driver ‘look’ left and right. On the front of the vehicle there’s an accelerometer. Data is collected by the Arduino and sent via the WiFly module. This adds rumble to the controller if you’re using one that has that ability.

It’s a big project already, but it sounds like [Blair] has not end of ideas for future versions. Right now he’s planning to increase the overall size which will let him explore places that aren’t as flat as his livingroom.

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A Mannequin Head + Arduino + Webcam = Lots of Creepy Fun!

styrofoam head robot

This mannequin head was purchased years ago on sale for less than $3. As with many things one sees while shopping, it didn’t have a purpose at the time, but seemed like it would be useful later. Add in an Arduino, some servos, and electronics parts that were acquire in a similar manner, and you have all the ingredients needed for a cool hack.

The build is well documented in the video after the break, and we especially like at 2:24 when who we suppose is the mom says “Look at this mess!” Apparently the next iteration will be a robot to clean everything up!

This iteration is quite impressive though, as it uses a webcam to track objects using a servomotor and lists the code used. For a view of it tracking stuff along with a view of the PC, fast forward to around 8:45. In addition to tracking the parts using the servo, the non-webcam eye changes color from green to yellow depending on if it’s tracking or not. It also featured a blinking necklace, which is also a plus in our eyes.

For more random head-like creepiness, be sure to check out [Boxie the Creepster]!

A zoom lens for your webcam

We need to find the kind of friends that [Dino] has. They seem to drop off all of their older, yet totally awesome, electronics with him once they’re through with the devices. One example of this is the Sony Handycam that came into his possession. He decided to crack it open and repurpose the 20x optical zoom lens for use with a webcam.

We always like [Dino's] style. You can tell that he has no idea if he’s going to be able to pull off his goal, but at the same time he has an intuitive sense that he’ll make it happen. In the video after the break he starts off investigating what components are in the camera. At first the lens is passing no light at all, but he just strips down parts until he can see through it.

There are a couple of servo motors which control zoom and focus. He removes those before attaching the CCD from a Logitech webcam. At the end of his video he shows a demo of the functionality, which is pretty finicky when focusing by hand. But we think this hack would make a fantastic camera for soldering projects, it just needs a custom controller so the motors can be once again used to adjust focus.

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