Building on the work of other Citizen Science efforts, [doctek]’s entry for the Hackaday Prize promises to detect pollution, identify chemicals, and perform other analyses with a simple handheld device. It’s a spectrophotometer, and [doctek] is putting some real engineering into this build.
A spectrophotometer is one of the simplest devices able to perform spectroscopy, requiring only a light source, a photoresistor, and some means of producing monochromatic light. By putting a sample in front of the photoresistor, the absorption spectrum of the sample can be measured. With this data, it’s a simple matter to identify the sample.
A light and a photoresistor are simple enough, but as with every precision measurement device, the devil is in the details. [doctec] is using new, low-noise, low-offset opamps, and precision references to get his data. Some of the parts in the schematic were actually designed in this century – a far cry from the ‘plug the photoresistor into the analog input’ projects we see so often.
[doctec] is using a Teensy 3.0 to drive the electronics and collect the data, and he already has the mechanics of this build pretty much figured out. It’s a great project that shows off some engineering skill, making it a great entry for The Hackaday Prize.
Laying hands on the supplies for most hacks we cover is getting easier by the day. A few pecks at the keyboard and half a dozen boards or chips are on an ePacket from China to your doorstep for next to nothing. But if hacking life is what you’re into, you’ll spend a lot of time and money gathering the necessary instrumentation. Unless you roll your own mini genetic engineering lab from scratch, that is.
Taking the form of an Arduino mega-shield that supports a pH meter, a spectrophotometer, and a PID-controlled hot plate, [M. Bindhammer]’s design has a nice cross-section of the instruments needed to start biohacking in your basement. Since the shield piggybacks on an Arduino, all the data can be logged, and decisions can be made based on the data as it is collected. One example is changing the temperature of the hot plate when a certain pH is reached. Not having to babysit your experiments could be a huge boon to the basement biohacker.
Biohacking is poised to be the next big thing in the hacking movement, and [M. Bindhammer]’s design is far from the only player in the space. From incubators to peristaltic pumps to complete labs in a box, the tools to tweak life are starting to reach critical mass. We can’t wait to see where these tools lead.
Chances are, you take color for granted. Whether or not you give it much thought, color is key to distinguishing your surroundings. It helps you identify fire, brown recluse spiders, and the right resistor for the job.
In the spotlight this week is a 1950s educational film called “This is Color“. It also happens to be a delightful time capsule of consumer packaging from the atomic age. This film was made by the Interchemical Corporation, an industrial research lab and manufacturer of printing inks. As the narrator explains, consistent replication of pigments is an essential part of mass production. In order to conjure a particular pigment in the first place, one must first understand the nature of color and the physical properties of visible light.
Each color that makes up the spectrum of visible rays has a particular wavelength. The five principal colors—red, yellow, green, blue, and violet—make possible thousands of shades and hues, but are only a small slice of the electromagnetic spectrum.
When light encounters a transparent material more dense than air, such as water or glass, it has to change direction and is bent by the surface. This is known as refraction. A straw placed in a glass of water will appear bent below the surface because the air and the water have different refractive indices. That is, the air and water will bend or refract different percentages of the light that permeates them. Continue reading “Retrotechtacular: Turn On the Magic of Colored Light”
[Charlie] has been making a DIY Spectrophotometer, and while it is a “shambling mess of information-age technology!” it is still much better than ours. Focused around an arduino, bits of lego, and a flashlight, this creative device rotates a diffraction grating (flake of compact disc) aimed at a photo resistor. As the light spectrum is passed over the sample, the photo resistor measures how much light is reflected and that data is passed back to a pc.
As nothing is as ever easy as it should be, a big problem popped up with using a servo. It was way too course, meaning the entire spectrum would be jumped over in 6 steps. A quick robbery of a gear assembly from a floppy disk drive and the motor movement was smoothed out. A little too well because 120 degrees of the servo is not quite enough to cover the entire spectrum. Oh well there is always room for improvement.