Touch sensors using lights and PVC?
Hmm... What would it be like to replace a physical switch with a touch sensitive switch.
Instead of using a beam of light to detect a triggering, we use a illuminated transparent PVC plastic.
This allows the interface to be more flushed into the wall.
How it will work, is that by touching the transparent plastic, you allow a small amount of light to escape. The circuit will detect this drop in light level and trigger the switch.
Pros: it looks cool, and is of lower maintenance than a physical switch. Its also cheaper then other options such as capacitive sensing
Cons: it can have false readings due to the use of light as a sensing medium.