apeg

The object(s) will be rubber, plastic, and cardboard. There will be multiple objects on the surface at a time. 

I am assuming a stylus-type solution will be costly, but you have given me a path to investigate. A quick search shows there are a number of different methods of screen touch detection, hopefully, one stands a chance at low-cost scaling. 

Thanks!

My goal is to see if I can economically create a large floor covering that would have the ability to detect when an object has been placed or removed from the surface. 

The idea originated from a BMI scale that uses electrical impedance to make rough calculations of the person's body composition. The problem there is the contact points are not connected on their own, it's the person who completes the circuit. 

I'm curious if there is a way to adapt the idea; if the contact points are connected via the surface material (a sheet of metal) and the impedance is constantly measured will placing or removing an object (of any material) create a change in the measurement, enabling me to trigger a change event, or better yet determine if something was removed or added to the surface. 

The only ace up my sleeve is that I don't need to know the weight/mass, only the change even and direction of. Weight/mass would be a great tertiary bonus, but not required. 

- I have a surface and am constantly measuring the impedance

- I placed an object on the surface, any material

Is it possible to use the impedance to detect a change? I'm not interested in the specific weight/mass, just interested if a "change" was triggered?

Take it a step further, would a rise or drop in impedance correlate with objects being added or removed?

Thanks!