I followed the Pseudo-Theremin example from Adafruit to practice using analog circuits. This project does not have a concept, but if I completed the project, I would have wanted to create a kissing booth that measures proximity of the kisser and plays sounds based on that proximity.
I created two different versions. For one version, the photoresistor is sensing the amount of light in the room and based on that reading, the frequency coming from the piezo buzzer is changing and LEDs are lighting up.
The other configuration uses a potentiometer to control the frequency and the LEDs.
