I want to do a system or robot that detects someone is using a desk. My question is which sensor or type of detection you would recommend me to use to allow to know someone is using a desk.
My choice are:
-Using an LED and LDR under the table if a person sits, it will detect. (If they wear a black cloth maybe it will not reflect back).
-Use an RFID tag, the person that uses the desk's touch with a tag.
-Distance sensor, in ebay this sensor is very cheap.
Not Automatic choice