Minimalist Low-Cost Colorimeter

In order to understand the natural world we need to measure it. Access to scientific machinery has been historically limited to formal academic institutions and research laboratories. Now, we can all build measurement tools to conduct our own science experiments!

In its simplest form, a colorimeter passes visible light of known wavelength and intensity through a liquid sample and measures the change in the light as it passes through. Comparing this value to a substance of known characteristics (control) we can infer particular differences between the two.
Typically, colorimeters produce wavelengths of light in the visible spectrum and often include components native to human vision. The human eye has evolved to process intensities of red, green, and blue light and thus our colorimeter utilizes the same wavelengths to reliably match what is seen with what is measured. By calculating the amount of each particular color present in the sample, we can compute the apparent color.

Colorimeters are widely used to monitor the growth of a bacterial or yeast culture. They're commonly employed to measure and monitor the color in various foods and beverages, including vegetable products and sugar. Aside from general research laboratories, colorimeters have many practical applications such as testing water quality by screening chemicals such as chlorine, fluoride, cyanide, dissolved oxygen, iron, molybdenum, zinc and hydrazine. They are also used to determine the concentrations of plant nutrients such as ammonia, nitrate and phosphorus in soil or hemoglobin in blood. More applications of colorimetry can be seen in color printing, textile manufacturing and paint manufacturing for precise quality inspection. But this tool tends to be expensive. A minimalist and affordable version of a transmission based colorimeter is proposed here. This colorimeter is in its first version and is open for beta testing. The goal of this was to reduce the cost of the device to as low as possible and not use access prohibitive technologies. We first presented it during our workshop at Maker Faire Rome 2017. It ain't pretty (yet) but its data will be sexy! ;) As they say, never judge a book by its cover or a colorimeter by its shabby looks! Version #2 will definitely see a substantial diminishment of indoor mounting tape! :D Stay tuned for more updates!