SparkFun XBee Explorer USB Sparkfun Originals, ZigBee & 802.15.4 Sockets it can detect transitions from

it can detect transitions from light to dark (lines) or even objects directly in front of it

Here at SparkFun we use them all the time

Graphical Datasheet

This DC Blower really moves some air

this lovely iron is a good choice

SparkFun XBee Explorer USB Sparkfun Originals, ZigBee & 802.15.4 Sockets it can detect transitions fromThis is a simple to use, USB to serial base unit for the Digi XBee line. This unit works with all XBee modules including the Series 1 and Series 2. 5, standard and Pro version. Plug the unit into the XBee Explorer, attach a mini USB cable, and you will have direct access to the serial and programming pins on the XBee unit. The highlight of this board is an FT231X USB to Serial converter. That? s what translates data between your computer and the XBee.