For my circuit, I decided to use an LDR, because to me touch-less circuits oftentimes include elements that could rely on sound or on light. I used a 2222 Transistor to switch the process of having my led light up when there is light, which felt somewhat useless. Instead, I have my circuit configured in a way that inverses this process and makes my LED light up when the LDR is not met with light (detects darkness).
The use of this circuitry could easily be attributed to smart lighting systems which turn the light on when it is dark. I was initially inspired by this process of smart systems as I have them integrated all over my room. It was very interesting looking at a very simplified version of this process and making it myself with the basic mechanics.
In this demo I use my hands to create the shadow over the LDR, but you could use anything to create a shadow, which is why I would say my circuit is hands-free, as no hand contact comes to the circuit for the light bulb to turn on, only shadow/light.
https://drive.google.com/file/d/1tnnrFYYkjPxqjYdOkOOp6tNWB11C8N0z/view?usp=sharing
