Earth Day: Environmental Sensors

April 22, 2015 by Brian Benchoff 18 Comments

Before you attempt to solve a problem, you must first study the problem. If there’s a problem with the environment, you must therefore study the environment at a scale never seen before. For this year’s Hackaday Prize, there are a lot of projects that aim to do just that. Here are a few of them:

[Pure Engineering]’s C12666 Micro Spectrometer has applications ranging from detecting if fruit is ripe, telling you to put sunscreen on, to detecting oil spills. Like the title says, it’s based on the Hamamatsu C12666MA spectrometer, a very tiny MEMS spectrometer that can sort light by wavelength from 340 to 780nm.

The project is to build a proper breakout board for this spectrometer. The best technologies are enabling technologies, and we can’t wait to see all the cool stuff that’s made with this sensor.

[radu.motisan]’s portable environmental monitor isn’t just one sensor, but an entire suite of them. The design of the project includes toxic and flammable gas sensors, radiation detectors, dust sensors, and radiation detectors packaged together in a neat, convenient package.

[radu] has already seen some success with environmental sensors and The Hackaday Prize; last year, his entry, the uRADMonitor placed in the top fifty for creating a global network of radiation sensors.

A DIY Fourier Transform Spectrometer

April 22, 2015 by Ethan Zonca 16 Comments

Typical spectrometers use prisms or diffraction gratings to spread light over a viewing window or digital sensor as a function of frequency. While both prisms and gratings work very well, there are a couple of downsides to each. Diffraction gratings produce good results for a wide range of wavelengths, but a very small diffraction grating is needed to get high-resolution data. Smaller gratings let much less light through, which limits the size of the grating. Prisms have their own set of issues, such as a limited wavelength range. To get around these issues, [iliasam] built a Fourier transform spectrometer (translated), which operates on the principle of interference to capture high-resolution spectral data.

[iliasam]’s design is built with an assortment of parts including a camera lens, several mirrors, a micrometer, laser diode, and a bunch of mechanical odds and ends. The core of the design is a Michelson interferometer which splits and recombines the beam, forming an interference pattern. One mirror of the interferometer is movable, while the other is fixed. [iliasam]’s design uses a reference laser and photodiode as a baseline for his measurement, which also allows him to measure the position of the moving mirror. He has a second photodiode which measures the interference pattern of the actual sample that’s being tested.

Despite its name, the Fourier transform spectrometer doesn’t directly put out a FFT. Instead, the signal from both the reference and measurement photodiodes is passed into the sound card of a computer. [iliasam] wrote some software that processes the sampled data and, after quite a bit of math, spits out the spectrum. The software isn’t as simple as you might think – it has to measure the reference signal and calculate the velocity of the mirror’s oscillations, count the number of oscillations, frequency-correct the signal, and much more. After doing all this, his software calculates an interferogram, performs an inverse Fourier transform, and the spectrum is finally revealed. Check out [iliasam]’s writeup for all the theory and details behind his design.

Hackaday Prize Finalist: An Un-noodly Spectrometer

November 10, 2014 by Brian Benchoff 17 Comments

And so we come to the final finalist bio for The Hackaday Prize. In only three days, we’ll know whether [fl@C@]’s RamanPi Spectrometer or one of the four other projects to make it into the finals round will be making it to space, or only Japan.

There are a surprising number of spectrometer projects out there on the Intertubes, but most of these setups only measure the absorption spectrum – literally what wavelengths of light are absorbed by the material being measured. A Raman spectrometer is completely different, using a laser to illuminate the sample, and measuring the scattering of light from the material. It’s work that has won a Nobel prize, and [fl@C@] built one with a 3D printer.

Bio below, along with the final video that was sent around to the judges. If you’re wondering who the winner of The Hackaday Prize is, even I don’t know. [Mike] and a few Hackaday overlords do, but the rest of us will remain in ignorance until we announce the winner at the party we’re having in Munich next Thursday.

Continue reading “Hackaday Prize Finalist: An Un-noodly Spectrometer” →

The Hackaday Prize Semifinalist Update

September 15, 2014 by Brian Benchoff 7 Comments

There are only a few more days until The Hackaday Prize semifinalists need to get everything ready for the great culling of really awesome projects by our fabulous team of judges. Here are a few projects that were updated recently, but for all the updates you can check out all the entries hustling to get everything done in time.

Replacing really, really small parts

acc The NoteOn smartpen is a computer that fits inside a pen. Obviously, there are size limitations [Nick Ames] is dealing with, and when a component goes bad, that means board rework in some very cramped spaces. The latest problem was a defective accelerometer.

In a normal project, a little hot air and a pair of tweezers would be enough to remove the defective part and replace it. This is not the case with this smart pen. It’s a crowded layout, and 0402 resistors can easily disappear in a large solder glob.

[Nick] wrapped the closest parts to the defective accelerometer in Kapton tape. That seemed to be enough to shield it from his Aoyue 850 hot air gun. The new part was pre-tinned and placed back on the board with low air flow.

How to build a spectrometer

spec

The RamanPi Spectrometer is seeing a lot of development. The 3D printed optics mount (think about that for a second) took somewhere between 12 and 18 hours to print. Once that was done and the parts were cleaned up, the mirrors, diffraction grating, and linear CCD were mounted in the enclosure. Judging from the output of the linear CCD, [fl@C@] is getting some good data with just this simple setup.

Curing resin and building PCBs

[Mario], the guy behind OpenExposer, the combination SLA printer, PCB exposer, and laser harp is chugging right along. He finished his first test print with a tilted bed and he has a few ideas on how to expose PCBs on his machine.

You don’t need props to test a quadcopter

blades Goliath, the gas-powered quadcopter, had a few problems earlier this month. During its first hover test a blade caught a belt and bad things happened. [Peter] is testing out a belt guard and tensioner only this time he’s using plywood cutouts instead of custom fiberglass blades. Those blades are a work of art all by themselves and take a long time to make; far too much effort went into them to break in a simple motor test.

DIY USB Spectrometer Actually Works

July 31, 2014 by Will Sweatman 32 Comments

image of diy spectrometer

When we hear spectrometer, we usually think of some piece of high-end test equipment sitting in a CSI lab. Sure, a hacker could make one if he or she put their mind to it. But make one out of a webcam, some cheap diffraction grating purchased off ebay and some scrap? Surely not.

[Renaud] pulls off this MacGyver like build with a detailed knowledge of how spectrometers work. A diffraction grating is used to split the incoming light into its component wavelengths. Much like a prism would. The wavelengths then make their way through a slit, which [Renaud] made from two pieces of highly polished brass, so the webcam sensor can see a specific wavelength. While the spectrometer-from-webcam concept isn’t new, the build is still impressive.

Once the build was complete, [Renaud] put together some software to make sense of the data. Though a bit short on details, we hope this build will inspire you to make your own spectrometer, and document it on hackaday.io of course.

THP Entry: The Improved Open Source Tricorder

June 11, 2014 by Brian Benchoff 27 Comments

Since [Gene Roddenberry] traveled back in time from the 23rd century, the idea of a small, portable device has wound its way through the social consciousness, eventually turning into things like smartphones, PDAs, and all the other technological gadgetry of modern life. A few years ago, [Peter Jansen] started The Tricorder Project, the start of the ultimate expression of [Mr. Roddneberry]’s electronic swiss army knife. Now [Peter] is building a better, smaller version for The Hackaday Prize.

[Peter]’s first tricorders borrowed their design heavily from The Next Generation props with a fold-out section, two displays, and a bulky front packed to the gills with sensors and detectors. Accurate if you’re cosplaying, but not the most practical in terms of interface and human factors consideration. These constraints led [Peter] to completely redesign his tricorder, disregarding the painted wooden blocks found on Enterprise and putting all the electronics in a more usable form factor.

A muse of sorts was found in the Radiation Watch, a tiny, handheld Geiger counter meant as an add-on to smartphones. [Peter] envisions a small ~1.5″ OLED display on top, a capacitive sensing wheel in the middle, and a swipe bar at the bottom. Basically, it looks like a 1st gen iPod nano, but much, much more useful.

Plans for what to put in this improved tricorder include temperature, humidity, pressure, and gas sensors, a 3-axis magnetometer, x-ray and gamma ray detectors, a polarimeter, colorimeter, spectrometer, 9-axis IMU, a microphone, a lightning sensor, and WiFi courtesy of TI’s CC3000 module. Also included is something akin to a nuclear event detector; if it still exists, there has been no nuclear event.

It’s an astonishing array of technology packed into an extremely small enclosure – impressive for something that is essentially a homebrew device.Even if it doesn’t win the Hackaday Prize, it’s still an ambitious attempt at putting data collection and science in everyone’s pocket – just like in Star Trek.

The project featured in this post is an entry in The Hackaday Prize. Build something awesome and win a trip to space or hundreds of other prizes.

Hyperspectral Imaging With A DSLR

May 18, 2014 by Brian Benchoff 12 Comments

It’s a relatively simple task to find evidence of helium by just looking at the sun; all you need is a prism, diffraction grating, and a web cam. DIY spectrometers have been around for ages, but most of them only produce a spectrum, not a full image complete with spectral data. Now it’s possible to take an image of an object, complete with that objects spectra using a DSLR, some lenses, a PVC pipe, and the same diffraction grating from your DIY interferometer.

The idea behind a hyperspectral imager is to gather the spectral data of each pixel of an image. The spectral data is then assembled into a 3D data cube, with two dimensions dedicated to the image, and the third dimension used to represent wavelength. There are a surprising number of applications for this technique, ranging from agriculture and medicine to some extremely creepy surveillance systems.

The authors of this paper (freakin’ huge PDF) used a piece of PVC pipe, three camera lenses, a diffraction grating, and a small paper aperture to construct their hyperspectral imager. Images are captured using a standard, multi exposure HDR method, assembling the raw data from the camera into a hyperspectral image with MATLAB.

There’s a ton of awesome info in the PDF, covering how the authors calibrated their system for different lighting conditions, interpreted the RGGB Bayer sensor in the camera, and a few examples of what kind of image can be constructed with this kind of data. That’s a recommended read, right there.

Thanks [Yannick] for the tip.