Yeah I'm using that rangefinder right now, and it is the easiest to implement out of several other Ultrasonic units I have used. Very little code required to get the desired distance output, no timing or counting to deal with. In addition, it sounds like you were planning on building your own... the bottom line is that its not worth your time to make something you could buy for a good price and it being a far superior device than what you could make. Just my 2 cents.