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LEDAtmosphericMonitoring-01

One of the recently released Maker Press books, Atmospheric Monitoring with Arduino, written by Patrick Di Justo and Emily Gertz, focuses on a few simple devices that utilize the Arduino platform to collect data about the environment. An LED-based Atmospheric Analyzer is one of these devices, and we have a kit for it available in the Maker Shed.

LED’s are not only useful as a light source, but as a light sensor as well. The LED Atmospheric Analyzer Kit leverages this to create an LED photometer – a device which measures how much blue, green, and red light is penetrating the atmosphere. By determining what wavelengths of light are present you can discern how much water vapor, smog, and haze are in the air. Using the instructions in the book along with the included Maker Shield and other components, you can build the photometer right on top of your Arduino.  Try setting it up near your window and share what you find with us!

Keep your eye out for other atmospheric monitoring kits based on this book!

Eric Weinhoffer

Eric is a Product Development Engineer at MAKE. He creates kits and sources products for sale in the Maker Shed, focusing primarily on manufacturing. Occasionally he writes about cool things for the blog and magazine.


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Comments

  1. Dave says:

    This is a cool project and learning tool, both for embedded computing applications and for atmospheric science. I bought and downloaded the accompanying pdf ebook, and there’s a lot to be gained from it.

    However…
    The process described in chapter 4 of the booklet for characterizing LEDs as colored light sensors bothers me. The author suggests using a tri-color LED as a source, introducing a very nice algorithm that mixes the three LED chip sources to produce light that spans the visible spectrum, from 700nm (red) to 350 nm (blue). This is then used to illuminate an LED being tested for use as a light sensor, to determine its peak wavelength sensitivity.

    Sounds great, but to my thinking, it suffers from a significant flaw. The three LED sources emit light in quite narrow wavelength bands, not continuously across the spectrum. While the resulting color mix will look to the (normal) human eye very similar to the same wavelength if it were selected from white light by a prism, in actuality, it consists of only a maximum of three peaks at different amplitudes.

    Naturally, a red sensor LED, for example, will show a maximum sensitivity very close to that emitted by the red chip in the tri-color illuminating LED. There is no other light at wavelengths nearby. The resulting sensitivity data can only show peaks near to the emitter peaks, and doesn’t indicate the sensitivity of the sensors to true (blackbody sourced) “white” light.

    Dave

    1. Eric Weinhoffer says:

      Dave,

      Thanks for pointing this out. You’re absolutely correct – the sensitivity readings from this device won’t really come close to the results you’d get from somethings that’s much more expensive. But that’s the whole idea – to build a cheap photometer with a few simple components instead of spending hundreds on a device that uses photon counting or something.
      For the low cost, and the data you can get out of it, this is a purely introductory kit to environmental monitoring, and I think it’s pretty cool.

      Cheers,
      Eric

  2. Getoffmylawn says:

    I doubt there’s a problem here. The led sensitivity curve isn’t complicated and three samples should describe it well enough for this purpose. Yes, NASA may need better calibration.

  3. Allen says:

    hey eric,
    that a great applicatain of LED, as i am looking about more different-2 application of LED tecnhomolgy as it is a very great source of light and used in wide idustries like marketing with outdoor led signs or television with LED display and many more… what else application could LED have???

    1. Eric Weinhoffer says:

      Hi Allen,

      LEDs are used often for decorative purposes, since they’re relatively cheap and come in a wide variety of sizes and colors (search YouTube for LED cube). RGB LEDs can be programmed to show many different colors or cycle between them, which is fun.

      They’re also becoming more popular in agricultural applications, since they can be programmed to emit the exact color that’s most beneficial for a certain plant during their grow cycle. Lettuce, for example, prefers blue light at certain stages and red light at others, so LEDs can used to cheaply give them the light they want.

      Cheers,
      Eric

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