Study on a Method of Resolving Common Misjudgment by Color Sensors of Robots used in Education
by Edison Suzuki
Abstract – LEGO® MINDSTORMS® EV3 is a robot kit that is often used for the introduction of Science, Technology, Engineering and Mathematics (STEM) education to students around the world. Using the color sensor and color detection mode that are standard on the EV3 and trying to determine the color of color blocks, the color discrimination was not successful every time due to individual differences of each color sensor. In the standard color identification mode of EV3, there were many misjudgments of color blocks, especially between red and yellow blocks. Therefore, another method for identifying a color block was considered in this study. RGB mode was used for color identification. G/B ratio was calculated for blue and green block identification, and R/G ratio was calculated for red and yellow block identification. These values did not overlap between the blue and green blocks and between the red and yellow blocks. The intermediate value of G/B ratio between blue and green blocks and intermediate value of the R/G ratio between red and yellow blocks were used to correctly distinguish the two blocks. As a result, the color blocks could be identified as almost 100%.