ATR stands for average true range.  It is an indicator that was designed to measure the average range of volatility of a security or index.  Most charting sites such as Stockcharts.com or bigcharts.com will have the indicator as an add on to their charts.  The computor will do the calculation and all you have to do is follow the wiggly line.

I would also like to add that in order to implement your plan you will probably have to develop the skills of a day trader as well as have the time to devote to a considerable amount of trading.  Is that what you want to do or do you have a carreer that might generate more income than trading stocks?  A first step towards making that decision might be to put yourself thru the chart school at Stockcharts.com.  It is free and should give you the basic tools needed to do some trading.

uh