Bring Doping, Microfluidics, Photovoltaics, and More Into the Home

Can you make a spectrometer for your home lab all from materials you have sitting around? We might not believe it from a less credible source, but this MIT course does indeed build a spectrometer from foam board using two razor blades as the silt cover and a writable CD as the diffraction grating. The coolest part is removing the metal backing of the CD.

mit_experiments_thumbHackaday reader [gratian] tipped us off about the course available from MIT courseware called Nanomaker. It boils down some fairly complicated experiments to the kind one can do in the home lab without involving thousands of dollars of lab equipment. The whole point is to demystify what we think of as complicated devices and topics surrounding photovoltaics, organic photovoltaics, piezoelectricity and thermoelectricity.

 

Spectrometers are used to analyze the wavelengths of a light source. Now that you have a measurement tool in hand it’s time to build and experiment with some light sources of your own. Here you can see an LED that is the topic of one of the course labs.

If you have a bit of background in chemistry this is a good step-by-step guide for getting into these types of experiments at home. It reminds us of some of the really cool stuff [Jeri Ellsworth] was doing in her garage lab, like making her own EL panels.

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Hacklet 122 – Spectrometers

There is always something interesting to find when browsing the projects on Hackaday.io. I’m always amazed at how much hackers can get done in their basements and home labs. One surprising trend I’ve found is the sheer number of spectrometer projects people across the globe are working on. I’ve always known what a spectrometer is, but I never knew so many hackers would want them. The numbers don’t lie though – plenty of hackers around the world want to measure the spectra of light — be it to test out a new LED, or determine the structure of an object. This week we’re checking out some of the best spectrometer projects on Hackaday.io!

ramanpiWe start with [fl@C@] and ramanPi – Raman Spectrometer. RamanPi is one of the first spectrometer projects on Hackaday.io. [fl@C@] entered his project in the 2014 Hackaday Prize, and was one of 5 finalists. As the name implies, ramanPi is a raman spectrometer, a type often used in chemistry. [fl@C@’s] original use for the machine was determining atomic bond angles. RamanPi uses 3D printed parts created with standard desktop printers wherever possible. A Raspberry Pi runs the system, originally a model B, though now I’m sure a Pi 3 would fit the bill. The detector is a Toshiba linear CCD.

 

dh-specNext up is [David H Haffner Sr] with DH 4.0 Spectrometer V 4 ( upgrade 2 ). [David’s] project doesn’t give a lot of background in the description text – he dives right in to the technical details of designing and building a spectrometer. His sensor is a JDEPC-OV04, which is a webcam module intended for use in laptops. Much of [David’s] recent work has been on the optical path. Optical spectrometers can use a diffraction grating and a slit to split light into spectra. [David] is using a recordable DVD as his diffraction grating. The slit is a bit more home-made. Two Gillette razor blades and an acetate strip are used to form an optical slit only 0.11 mm wide. [David] has already used his spectrometer to analyze crude oil.

pure-engNext we have [Pure Engineering] with C12666MA Micro-Spectrometer. Electro-Optics manufacturer Hamamatsu has created an optical spectrometer in a fingertip sized can. Their C12666MA micro-spectrometer sounds like it must be magic — and it is. The magic of Microelectromechanical systems (MEMS) have brought this device to life. Bringing one of these devices up isn’t exactly an easy task though. [Pure Engineering] has designed a breakout board for the C12666MA. They’ve even included a 404nm laser diode and a white LED for illumination. The board can plug into a standard Arduino header.

adamFinally, we have [Adam] with Handheld VNIR Spectrometer. VNIR in this case stands for visible and near-infrared. [Adam] created this device so he could learn how spectrometers worked. That’s a noble purpose if I ever heard one. He is building his system to be portable, so he can take measurements outside the lab. The sensor is a Sony ILX511B linear CCD. An Arduino nano reads the CCD and passes the data on to a PC for analysis. [Adam’s] diffraction grating is a concave holographic affair from Public Lab. [Adam] is also using an acetate slit purchased from Public Lab. Illumination enters via a fiber optic bundle.

If you want to see more spectrometer projects, check out our new spectrometer projects list. See a project I might have missed? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Hackaday Prize Entry: A Visible Spectrophotometer

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.

Earth Day: Environmental Sensors

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

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

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.

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The Hackaday Prize Semifinalist Update

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

accThe 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

uv[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

bladesGoliath, 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.