This psuedo code illustrates a routine for performing action based on sensor readings 
utilizing hysteresis to prevent jumping around of values 

This code is un-tested and imperfect in many ways, 
it is provided to give a starting point for writing ADC functions utilizing hysteresis 

Please let me know if you have better methods for doing similar work or if this proves not to work


Some Variables:
currentMovingDirection = 0 (this would be -1 for down and +1 for up)
lastMovingDirection = 0 (same)
lastADCPinValue = 0

jumpAmount = 0
initialCalibrationTime = 5
startTime = Get Current Time Function

lowValue = Get Current ADC Pin Value Function
highValue = Get Current ADC Pin Value Function

Initial Calibration Routine:
while (currentTime - startTime <  initialCalibrationTime)
{
	currentADCPinValue = Get Current ADC Pin Value Function
	if (currentADCPinValue <  lowValue)
	{
		lowValue = currentADCPinValue
	}
	else if (currentADCPinValue >  highValue)	
	{
		highValue = currentADCPinValue
	}

	jumpAmount = highValue - lowValue
}

Utilizing The Calibration:
while (true)
{
	currentADCPinValue = Get Current ADC Pin Value Function	
	if (currentADCPinValue > lastADCPinValue)
	{
		currentMovingDirection = 1
	} 
	else if (currentADCPinValue < lastADCPinValue)
	{
		currentMovingDirection = -1
	}
	else
	{
		currentMovingDirection = 0
	}

	if (currentMovingDirection == lastMovingDirection)
	{
		realADCPinValue = currentADCPinValue
		lastADCPinValue = currentADCPinValue
	}
	else if (currentMovingDirection = -1 and currentADCPinValue < lastADCPinValue - jumpAmount)
	{
		realADCPinValue = currentADCPinValue
		lastADCPinValue = currentADCPinValue
	}
	else if (currentMovingDirection = 1 and currentADCPinValue > lastADCPinValue + jumpAmount)
	{
		realADCPinValue = currentADCPinValue
		lastADCPinValue = currentADCPinValue
	}
	else
	{
		Don't Move
	}
	
}