DIY Spectrophotometer

The parts listed here can be used to construct a simple spectrophotomer, which illuminates a sample in a cuvette with an LED and then measures the amount of light transmitted through the sample with a photoresistor (on the opposite side of the cuvette). The voltage across the photoresistor can be measured using an Arduino. In short, as the absorbance of the sample increases, the voltage across the photoresistor will decrease.

Several parts are listed here, including:
1) An enclosure that will hold an Arduino and the rest of the LED/photoresistor circuit.
2) A simple cuvette holder that grips the cuvette and holds the LED/photoresistor in place on either side of it.
3) A more advance cuvette holder with multiple pieces (LED holder, cuvette/photoresistor holder, and a cuvette removal tool), which fully conceals the cuvette from ambient light.