From David Cook's Robot Room comes a new project for robot builders: a laser pointer sensor. You can use it to trigger an action when a laser pointer is directed onto the sensor. It could be used as a way of remote starting a robot for a competition or for any other project that needs to be remotely triggered. As always David provides a clear explanation of how the circuit works, along with a schematic, parts list , even a video demonstration of the completed sensor. Along the way, you'll learn about the TI TLV3702 comparator, the 7474 logic chip, and decoupling capacitors. All you'll need is a few dollars of parts and a breadboard to build the laser detector circuit.