I am interested in detecting if an object (e.g. small box made of non-conductive material like plastic/acrylic/wood) is placed on top of a surface (e.g., a table), I don't need to identify the object, I just want to know if it is there.
There are various methods to doing this, but I wanted the easiest/cheapest way. I first thought of using a Mini Photocell ($1.50), which is a simple light sensor, however, this will not work if the room is initially dark.
Then I found the Optical Detector / Phototransistor - QRD1114 ($0.95).
- I believe QRD1114 should work regardless of lighting conditions, since this uses IR?
- I need to consider the approaching object (e.g., small box) should be able to reflect IR?
- Any ideas on the IR beam?
The detecting sensor must be very small and cheap.