Some of you may remember the SCiO, originally a Kickstarter darling back in 2014 that promised people a pocket-sized micro spectrometer. It was claimed to be able to scan and determine the composition of everything from fruits and produce to your own body. The road from successful crowdsourcing to production was uncertain and never free from skepticism regarding the promised capabilities, but the folks at [Sparkfun] obtained a unit and promptly decided to tear it down to see what was inside, and share what they found.
The main feature inside the SCiO is the optical sensor, which consists of a custom-made NIR spectrometer. By analyzing the different wavelengths that reflect off an object, the unit can make judgments about what the object is made of. The SCiO was clearly never built to be disassembled, but [Sparkfun] pulls everything apart and provides some interesting photos of a custom-made optical unit with an array of different sensors, various filters, apertures, and a microlens array.
It’s pretty interesting to see inside the SCiO’s hardware, which unfortunately required destructive disassembly of the unit in question. The basic concept of portable spectroscopy is solid, as shown by projects such as the Farmcorder which is intended to measure plant health, and the DIY USB spectrometer which uses a webcam as the sensor.
We don’t know why [stoppi71] needs to do gamma spectroscopy. We only know that he has made one, including a high-voltage power supply, a photomultiplier tube, and–what else–an Arduino. You also need a scintillation crystal to convert the gamma rays to visible light for the tube to pick up.
He started out using an open source multichannel analyzer (MCA) called Theremino. This connects through a sound card and runs on a PC. However, he wanted to roll his own and did so with some simple circuitry and an Arduino.
Continue reading “Arduino does Hard Science”
Ten years ago, MIT researchers proved that it was possible to look through an envelope and read the text inside using terahertz spectroscopic imaging. This research inspired [Barmak Heshmat] to try the same technique to read a book through its cover. A new crop of MIT researchers led by [Heshmat] have developed a prototype to do exactly that, and he explains the process in the video after the break. At present, the system is capable of correctly deciphering individual letters through nine pages of printed text.
They do this by firing terahertz waves in short bursts at a stack of pages and interpreting the return values and travel time. The microscopic air pockets between the pages provide boundaries for differentiation. [Heshmat] and the team rely on these pockets to reflect the signal back to a sensor in the camera. Once they have the system dialed in to be able to see the letters on the target page and distinguish them from the shadows of the letters on the other pages, they use an algorithm to determine the letters. [Heshmat] says the algorithm is so good that it can get through most CAPTCHAs.
The most immediate application for this technology is reading antique books and other printed materials that are far too fragile to be handled, potentially opening up worlds of knowledge that are hidden within disintegrating documents. For a better look at the outsides of things, there is Reflectance Transformation Imaging.
Continue reading “MIT Researchers Can Read Closed Books (and defeat CAPTCHA)”
Spectroscopy is one of the most useful tools in all of science, and for The Hackaday Prize’s Citizen Science effort [esben] is putting spectroscopy in the hands of every high school student. He’s built a super cheap, but very good spectrophotometer.
The idea of a spectrophotometer is simple enough – shine light through a sample, send that light through a diffraction grating, focus it, and shine the light onto a CCD. Implementing this simple system is all about the details, but with the right low-cost lenses and a 3D printed enclosure, [esben] has this more or less put together.
Of course, lenses and diffraction gratings are relatively simple. You need real data, and for this we can turn to another one of [esben]’s projects in the Hackaday Prize. It’s a breakout board for a linear CCD module, able to capture the spectrum coming off a sample with incredible precision. This is how real spectrophotometers are put together, but because of the difficulties in driving a CCD, not many people have put one of these together.
Both of these projects are finalists for in the Citizen Science portion of The Hackaday Prize. That’s an awesome result for what is a complete system for learning about spectroscopy with a device that’s also able to produce some high-quality data, too.
If you understand technology, there were a lot of things hard to explain on Star Trek. Transporters, doors that were smart enough to open unless you hit them during a fight, and the universal translator all defy easy explanation. But one of the hardest things to explain were Mr. Spock’s sensors. From the ship or with a tricorder, Spock could sense at a distance just about anything from chemical compositions, to energy, and even the presence of life (which, today, at least, is difficult to determine even what that means).
Remote sensing would have a very distinct use in today’s world: finding terrorist bombs earlier. A recent article published on New Scientist by [Debora MacKenzie] points out that stopping attacks like the recent one in Brussels is difficult without increasing congestion. For example, putting checkpoints at doors instead of inside transit stations is common in Asia, but causes lines and delays.
The United States has used ion mobility spectrometry (IMS) to detect explosive traces on swabs (using machines like the one on the left). However in the early 2000’s they experimented with a version of the device that used puffs of air to determine if people had explosives while they passed by the machine. By 2010, officials decided the machines broke down too often and stopped using them.
Remote Sensing in Practice
According to an expert at Rand Corporation, remote sensing is likely to employ imaging or sniffers. However, imaging solutions are easy to fool since a bomb can take the shape of an ordinary object. Sniffers, including biological sniffers (known as dogs), are harder to fool. The problem is that deploying thousands of dogs to cover the world’s airports is difficult.
Continue reading “Remote Sensing Bombs Could Stem Terrorism”
There are hackers who have soldering setups on the dining room table, and then there are hackers who have scanning electron microscopes in their living room. [Macona] is part of the latter group, with a Hitachi S-450 SEM he’s repaired and modified himself. [Macona] has documented the whole thing on Hackaday.io. The Hitachi came to him and a friend as a derelict. First it was broken, then stored for 10 years. It turned out the problem was a high voltage cable cut and spliced with electrical tape. The tape eventually broke down and shorted out the 500V supply. Thankfully the rectifier diodes were the only parts that needed to be replaced.
The SEM sprang to life and gave [Macona] and a friend their first images. However, SEMs are finicky beasts. Eventually the filament burned out and needed to be replaced. New filaments are $500 US for a box of 10, which is more than [Macona] wanted to spend. It turns out filaments can be built at home. A bit of .089mm tungsten wire and a spot welder were all it took to fix the issue. Next to go bad was the scan amplifier. While SEMs use many exotic parts, the Hitachi used relatively common Sanyo STK070 audio amplifiers for the purpose – an easy fix!
One thing that makes this SEM unique is the is Energy Dispersive X-Ray Spectroscopy (EDX) unit attached to it. The fragile liquid nitrogen cooled sensor was working, but the 1980’s era signal processing computer was a bit too old to bring up. A friend and fellow SEM hobbiest gave [Macona] a slightly newer Kevex Sigma Gold signal processor, which was nearly a plug and play upgrade for his machine. The new processor processor also gave him digital beam controls and a digital output which could be used to capture images with a PC.
Once all the connections were made, the EDX worked surprisingly well, even finding gold in a uranium ore sample placed in the microscope.
Now that old scanning electron microscopes being retired, it’s only a matter of time before more us get a chance to join the ranks of [Jeri Ellsworth], [Ben Krasnow] and [Macona] with our own personal SEMs!
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.