Project Summary

    A colorimeter is a device that analyzes a substance by observing how different wavelengths of light are absorbed by the object. Using multiple frequencies allows the device to learn more about a substance. Most colorimeters just find the concentration of a substance, but they could possibly do much more. The goal of this project was to create an affordable, compact colorimeter that could be used to accurately identify and analyze liquids.

    A colorimeter was designed and constructed using eight brightness controlled LEDs, two phototransistors (to accurately detect light passing through and refracted by the substance), and a microcontroller that interfaces with a computer. It shines each LED through the unknown solution, analyzes the readings, and decides what the substance is by comparing them to those in its internal substance library.

    It was tested with many substances, scanning them ten times in a random order. This included colored substances as well as eight clear substances. Out of 160 trials, it only missed two for 98.75% accuracy. The factors causing this error were identified so they can be fixed in upcoming versions. In future versions glass vials and a secure vial holder will be used.

    This prototype can lead to an affordable yet accurate colorimeter perfect for small schools, labs, and police stations that normally couldn't afford a full spectrometer or spectrophotometer. It would be ideal for easy material scanning at security checkpoints. Solar powered versions could be used to test water in developing countries without requiring additional resources.

An Alternative Optical Analyzer


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