As explained by Arduino to Go, each color band on the resistor corresponds to a number but this can differ depending on the band's placement. It's not complicated, but the sheer number of colors ...

ELENCO CC-100 CC100 RESISTOR COLOR CODE CALCULATOR USA Shipping, Product details Product Dimensions ‏ : ‎ 3 x 2 x 1 inches Date First Available ‏ : ‎ November 24, 2020 Manufacturer ...

How the resistor color-code bands work At the heart of the project is an Arduino Nano clone and a potential divider that measures the resistance of the test resistor against a known fixed value.