Open source spectrophotometer - Revision history

Fnord: Undo revision 45944 by IgAZwmawpK (talk)

2015-01-01T00:21:54Z

Undo revision 45944 by IgAZwmawpK (talk)

← Older revision		Revision as of 17:21, 31 December 2014
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	Desire is to create a spectrophotometer for general use, as part of an open-source biotech hardware toolkit.		Desire is to create a spectrophotometer for general use, as part of an open-source biotech hardware toolkit.

	==THE STORY SO FAR==~~[[File:Past1.jpg]]~~		==THE STORY SO FAR==
	~~[[File:Past2.jpg]]~~
	~~[[File:Present1.jpg]]~~


	===BASIC BANALITIES OF PHOTONS===		===BASIC BANALITIES OF PHOTONS===

IgAZwmawpK at 21:14, 30 December 2014

2014-12-30T21:14:07Z

← Older revision		Revision as of 14:14, 30 December 2014
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	Desire is to create a spectrophotometer for general use, as part of an open-source biotech hardware toolkit.		Desire is to create a spectrophotometer for general use, as part of an open-source biotech hardware toolkit.

	==THE STORY SO FAR==		==THE STORY SO FAR==[[File:Past1.jpg]]
			[[File:Past2.jpg]]
			[[File:Present1.jpg]]


	===BASIC BANALITIES OF PHOTONS===		===BASIC BANALITIES OF PHOTONS===

AlSweigart at 06:26, 8 February 2011

2011-02-08T06:26:38Z

← Older revision		Revision as of 23:26, 7 February 2011
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			{{Template:OutOfDate}}

	==MISSION STATEMENT==		==MISSION STATEMENT==

Beng: /* BASIC BANALITIES OF PHOTONS */

2010-03-30T00:46:25Z

BASIC BANALITIES OF PHOTONS

← Older revision		Revision as of 17:46, 29 March 2010
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	How to get specific wavelengths of light? First, use a light source which contains many wavelengths, then filter the light or diffract the wavelengths spatially. Although fluorescence (ex: phosphors) can be used to increase the number of wavelengths, a mere filter or prism can only separate the types of light already within the source.		How to get specific wavelengths of light? First, use a light source which contains many wavelengths, then filter the light or diffract the wavelengths spatially. Although fluorescence (ex: phosphors) can be used to increase the number of wavelengths, a mere filter or prism can only separate the types of light already within the source.

	~~We will in general be using [[diffraction grating]]s and Mike_Kan has described some basic elements of how to use them.~~

	~~Because we want to use this for biotechnology applications, we can come up with some desired wavelengths: Proteins, for example, are quantifiable by the absorbance~~ and~~/or fluorescence of tyrosine~~ and tryptophan, which absorb ~280 nm and emit from 300-350 nm. Other interesting wavelengths include DNA (260 nm) NADH (460 nm), chlorophyll (680 / 700 nm) and a variety of chromogenic reagents which can indicate very low concentrations of heavy metals.		More detail and extra notes in
			[[Light source]]s
			and
			[[Diffraction Grating]]s

			Because we want to use this for biotechnology applications, we can come up with some desired wavelengths: Proteins, for example, are quantifiable by the absorbance and/or fluorescence of tyrosine and tryptophan, which absorb ~280 nm and emit from 300-350 nm. Other interesting wavelengths include DNA (260 nm) NADH (460 nm), chlorophyll (680 / 700 nm) and a variety of chromogenic reagents which can indicate very low concentrations of heavy metals.

	===ARDUINO GARBAGE + MOTOR SPEC===		===ARDUINO GARBAGE + MOTOR SPEC===

SpammerHellDontDelete: original piece

2010-03-30T00:42:11Z

original piece

New page

==MISSION STATEMENT==

Desire is to create a spectrophotometer for general use, as part of an open-source biotech hardware toolkit.

==THE STORY SO FAR==

===BASIC BANALITIES OF PHOTONS===

An absorbance spectrophotometer is a devices used to shine a specific wavelength of light through a sample, in order to divine the type and concentration of chemical species within the sample.

How to get specific wavelengths of light? First, use a light source which contains many wavelengths, then filter the light or diffract the wavelengths spatially. Although fluorescence (ex: phosphors) can be used to increase the number of wavelengths, a mere filter or prism can only separate the types of light already within the source.

We will in general be using [[diffraction grating]]s and Mike_Kan has described some basic elements of how to use them.

Because we want to use this for biotechnology applications, we can come up with some desired wavelengths: Proteins, for example, are quantifiable by the absorbance and/or fluorescence of tyrosine and tryptophan, which absorb ~280 nm and emit from 300-350 nm. Other interesting wavelengths include DNA (260 nm) NADH (460 nm), chlorophyll (680 / 700 nm) and a variety of chromogenic reagents which can indicate very low concentrations of heavy metals.

===ARDUINO GARBAGE + MOTOR SPEC===

Found an excellent low-cost project already written up by a brazilian group<sub>1</sub>, using a white LED, cd-rom diffraction grating, stepper motor, and phototransistor. First goal: implement using Arduino!

===CCD CAMERA SPEC===

Need more wavelengths and less moving parts for successful low-cost biotechnology laboratory.

Stanford group<sub>2</sub> uses 0.5 and 1 um amplitude gratings directly above a CCD, they get 1.7 nm bandwidth / pixel. We could use a digital SLR CCD, which we've heard have smaller elements (the paper's CCDs were ~10 um squares). There are a wide variety of amplitude (AKA transmission) gratings available, but a few things still need to be figured out:

1: UV is absorbed by glass and plastic, so we can't build a UV-sensitive devices with a transmission grating unless it is quartz / fused silica.

2: Need to understand the equation relating the grating distance and blaze angle to the zero and first order characteristics of the diffraction.

[http://www.optometrics.com/products_gratings_t.html transmission][http://www.thorlabs.com/NewGroupPage9.cfm?ObjectGroup_ID=1123 grating][http://search.newport.com/i/1/nav/1/q1/Richardson%2520Gratings/x1/product_brand suppliers]

[http://www.lightsmyth.com/products/premium_transmission_gratings/index.php fused silica transmission grating]

1. Germano Veras et al. 2009 "A portable, inexpensive and microcontrolled spectrophotometer based on white LED as light source and CD media as diffraction grid" Talanta 77(3), 1155-115

2. Gaylin M. Lee et al. 1997 "Miniature spectrometers for biochemical analysis" Sensors and Actuators A 58 p. 61-66