A Character Input Method for Smart Glasses that Allows You to Enter One Character in One Step with One Thumb

At HCII2023, we announced a method to input one character in two steps. The user holds the smartphone and operates it with their thumb. The first step is to select a group of five letters by rotating your thumb at the carpometacarpal joint (the joint at the base of your thumb) and sliding the tip of your thumb across the screen. The second step is to select one letter within that group by tapping or flicking. In this research, that second step is replaced the method to select a letter by bending your thumb. The user rotates the thumb like the same as the previous method. When a letter group containing the letter that you want to enter appears on the input guidance window, start bending your thumb to select that group. Then bend your thumb until you see that letter in the guidance window. When it appears, move your thumb off the screen and input. This allows you to enter one character in one operation. Character input can be done by rotating the thumb and bending and straightening the thumb, both of which are easy movements. There is no longer a time loss between group selection and letter selection that existed in the previous method. Therefore, character input speed has improved. In experiments with beginners, the speed increased by up to 20% after entering around 250 characters. A Mann-Whitney U test confirmed that there was a significant difference.