We need to get some kind of a simple sensor, that can sense someone is standing close to a product . But, it has to be behind plastic, and not seen at all . We only need to detect someone 1 meter away from the product .
- Using PIR sensors is a problem because its covered.(is it possible somehow?)
- using any lights resistors/sensors also a problem when it covered .
- ultrasonic is a problem because its too big and battery eating .
- infra is no brainer because its covered .
Is there a simple yet powerful sensing method that i am missing here, that takes no energy and detects a small distance human body ?