WEEK 8

Literature Review

Existing Design

1.  Egg Torte

            The “Egg Torte” micromouse designed by Kato-san won first place in Japan’s Half Sized Micromouse Competition in 2010. It is constructed on a printed circuit board which houses the microcontroller and can be seen in Figure 1. It runs on lithium batteries and operates using four motors, but only two wheels. It appears that one motor turns each wheel and the second set of motors is used to make the mouse run faster after the first mapping run of the maze.

            In demonstrations the Egg Torte travels at a visibly faster rate in long, straight segments of the maze. This design uses four IR sensors to navigate the maze: two looking forward and two looking out to the sides. The front two sensors look across each other to the opposite sides of the maze. By comparing the intensity of IR returned to either sensor, the mouse can determine whether it is travelling down the center of a path in the maze and whether there is a wall directly in front of it. The other two sensors seem to be looking at the walls to find openings where the maze branches away from the current path.

            On the underside of the mouse, there are two pads supporting the front and rear of the mouse to lower friction and prevent the underside of the circuit board from dragging on the ground. This mouse’s algorithm displays some impressively efficient features, such as moving diagonally through zigzags and rounding out its turns, narrowly missing the wall at the inner edge of a corner.

                                        Figure 1: The Egg Torte Micromouse

                  2.   Min7

            The Min7 is a micromouse design that won the All Japan Micromouse competition in 2011. Its design also uses a circuit board with embedded microcontroller as a chassis, but uses only two motors to power its four wheels. The design again uses a lithium polymer battery and infrared sensors, and Figure 2 shows the visor which is placed over the sensors to reduce noise. Weighing in at only 90 grams and having a 10 x 7.5 cm profile, this mouse can reach speeds of up to 3.5 meters per second, solving a maze at competition in four seconds. This design’s algorithm also employs corner cutting and diagonal movement techniques.

                                             Figure 2: Min7 Micromouse