Looking for a sensor

[rdevine]

Looking for a sensor that is small (size of quarter), uses passive rfid technology and will tell me if something is touching it. Possibly just store a binary value if something is touching it or not. Looking to be able to stick the sensor ina location and know if an object is touching it. The read range can be short or long. What type of tag would I be looking for? Willing to discuss the option to have it created for a fee.

Love to hear the groups thoughts

[gohan]

A tag is passive, no battery while a sensor that can react needs some sort of power to react to touch and store the information, so unless they invented something new that I don't know, you are a bit out of luck. What is the project you are looking to accomplish?

[rdevine]

The project is that I have a box with objects in it. Each object has a placeholder within the box. I want to place a sensor in the bottom of each placeholder and have it tell me if an object is within the placholder or not. With RFID i want to know what is missing without opening the box.