When working with automated special effects, the most important part is making sure that they are well timed. For live events such as a haunted house, the best way to get the timing right is to use sensors to detect where your guests are and when they reach various locations. So for this Halloween, I am doing a series of projects that demonstrate different sensors that can be used to automate a haunted house.
Last week I showed how to use a pressure plate switch to activate special effects. This week, I am going to show you how to make a simple proximity sensor. This is basically just an infrared LED and a phototransistor. When a person stands near the sensor, some of the light from the LED is reflected back to the detector. The output signal of the detector can be monitored by an Arduino and used to activate special effects when the person is close enough.
See the full series here.