Tutorial:Shake Detection

About

Here is a simple example of detecting when the user shakes the device. It only uses the X and Y axis which is sufficient for general purposes(like shake to generate x event). You can modified the sensitivity as well.

Code

 #include "DragonFireSDK.h"


//Last Tiltx/y are used to determine distance of current vs last tilt.  
int iLastTiltx =0;
int iLastTilty=0;
//iCurx/y is used to get the current tilt
int iCurx;
int iCury;
//iDistancex/y are used to hold the actual distance between cur and last. They get summed up to iTotal. 
int iDistancex=0;
int iDistancey=0;
 //iTotal used to keep a running record oftilt changes(thoughb it does get reset after a period of inactivity)
int iTotal=0;
//the thresh hold is the total running distance of tilts before an event happens.  5000 means they are shaking it on purpose
//change this number to decrease or increase shake time required
int iTotalThreshold = 5000;
//iDelay is used to prevent the successful shake event from happening many times in a row.  
//For my purposes, this method was fine but you may want to come up with a different way if firing the event x2 would be deterimental
int iDelay = 30;
//the iDelayThreshold is used to prevent an event from happening mujltiple times.  Set at 45, it means 1.5 seconds.  Increase or decrease this
//delay between potential events firing as suits your purposes.
int iDelayThreshold = 45;
// iSamecounter keeps track of inactivity.  If the tilt stays the same for a period of time, it will reset the iTotal counter.
int iSameCounter =0;
void AppMain()
{

}



void AppExit()
{

}
void OnTimer()
{
	
	//Get current tilt x and y
	iCurx = TiltGetx();
	iCury = TiltGety();

	//Check if the last tiltx/y = current.  If so, we need to add a +1 to the same counter
	if ((iCurx == iLastTiltx) && (iCury == iLastTilty))
	{
		
		iSameCounter++;
	}
	//If same counter > 25(almost a second), reset iTotal
	if ((iSameCounter > 25))
	{
		iTotal = 0;
		iSameCounter = 0;
	}

	//Some math to determine distance between points.  pretty basic but if you are like me
	//it took a while for high school geometry to come back...
	iCurx = iCurx -iLastTiltx;
	iCurx = iCurx * -1;
	iCury = iCury -iLastTilty;
	iCury = iCury *-1;


	iDistancex = iCurx + iLastTiltx;
	iDistancey = iCurx + iLastTilty;
	iTotal = iDistancex + iDistancey;
	if (iTotal > iTotalThreshold && iDelay > iDelayThreshold)
	{
		iDelay =0;
		Vibrate();
		iTotal = 0;
	}
	iLastTiltx = TiltGetx();
	iLastTilty = TiltGety();
	iDelay++;

	
}