How To Build A Motion Sensor

Been reading tons of sites and watching strange tutorials on how to build a motion sensor.

BUT this one really got my attention:

http://antiadvertisingagency.com/wp-content/pdfs/how-to-article.pdf

Oh Hey…Say WHAT 20th century?!?!

A CD player!! *smh*

Can you even find one of those outside of the 90’s ?!?

Didn’t think so…