Laser-Triggered Sound Player
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This project creates a laser trip-wire that when triggered plays a sound. The sound is stored on an SD card in MP3 format, so it can be any sound you like - like a voice recording or your favorite tune.
Laser-Triggered Sound Player Schematic
When the laser is pointing at the photoresistor, the resistance of the photoresistor is low. This makes the voltage to the transistor low so that it is off.
When someone crosses the beam, the light no longer hits the photoresistor for a brief moment, so the resistance of the photoresistor becomes high, and the transistor turns on. When the transistor turns on, the IO2 input of the MP3 player is pulled low and it starts to play.
Laser-Triggered Sound Player Parts List
How to Build the Laser-Triggered Sound Player
You can build this on a stripboard as shown below.
Make sure you cut the strips beneath the mp3 module so that the left row of pins isn't connected to the right (except for ground, you want those sides to be connected). And cut the strips next to ID and D+ from the usb breakoutboard so that those pins aren't connected to the other things on those strips.
Make it your own
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