Basic algorithm for using Wiimote to control cursor

Using the Wiimote as a way to operate a mouse cursor on a PC is an idea that has come across the minds of many in the home brew community. GlovePIE allows for this task to be done using algorithms related to the camera within the Wiimote and the IR sensor bar used with the Wii console.

This is a recent project I have started and am hoping to expand upon in order to provide a precise and easy-to-use experience for PC users who may opt to using a Wiimote to operate their PCs.

This entry will focus on the basic algorithm I will be using to perform the function of operating a mouse cursor.

These algorithms simply allow you to move the cursor around the screen. There are no button assignments made yet, thus there is no "left-clicking" or "right-clicking." The following are descriptions of the functions and numbers found in the first equation:

• mouse.CursorPosY : The mouse cursor position on the Y axis. Assigning a correct algorithm to this variable allows the user to move the cursor up and down.
• round : Allows us to round up the equation within the first set of parenthesis, thus giving the user smoother mouse movement on the screen.
• wiimote1.dot1y : The Wiimote relies on two IR points provided by the sensor bar in order to give more accurate readings. In GlovePIE, these points are referred to as "dots." Thus, dot1y is the y-position of one of the points being detected.
• wiimote1.dot2y : This is the y-position of the second IR point being detected.
• ((wiimote1.dot1y+wiimote1.dot2y)/2)/760*1200 : This equation allows us to average the two y-positions, thus giving a more accurate reading.
• ((wiimote1.dot1y+wiimote1.dot2y)/2)/760*1200 : 760 is the maximum height reading that can be achieved using the Wiimote, with 0 being the lowest. This number can be determined by doing a simple test with the debug function where debug = wiimote1.dot1y. The average is divided by this number in order to create a percentage and a number between 0 and 1.
• ((wiimote1.dot1y+wiimote1.dot2y)/2)/760*1200 : 1200 is the pixel resolution of the height of the monitor currently being used. The previous part of the equation is multiplied by the height of the resolution in order to pinpoint exactly It is important that this number is adjusted according to the resolution of the monitor being used.

The variables in the algorithm reflecting the x-axis position are similar to the algorithm of the y-axis. However, due to the way the Wiimote was designed, the x-axis is inverted. In order to reflect this, the length resolution, 1920, is subtracted by round(((wiimote1.dot1x+wiimote1.dot2x)/2)/1012*1920)