LDC1614EVM other materials

Hello,

Can you post an image or a sketch of your setup? It would help greatly to understand what exactly you have.

Hello,

this is just a demo, but I want to let this setup work. The metal sheet is 0.7 mm thick.

Is the white separation between the metal and the coils a spongy type?

How are the coils secured when you press on the metal?

This application is what we call Touch-on-Metal, and we have a TI design that completely describes how to build such systems. Please take a look: www.ti.com/.../tida-00314

Mechanical considerations are very important, to make sure that the distance for the pressed button changes while for the rest of the buttons it's not.

For your case I would place a rigid separator between the coils, so the metal rocks over it.

Hello,

I tried to change some variables. I used rigid separator sticked with adhesive tape on the coils and all sticked to the metal sheet (0.7mm thick) as shown in the second picture.

In the third picture the results. It's better than before, by the way it detects also if the finger doesn't touch the surface. I think that the skin effect "gets out" the metal sheet, so corrections are needed in the register setup. Suggestion on what is the right parameter to setup and how to calculate them? (for example I cannot find the L of the EVM coils)

Best Regards

hello,

If the distance between the metal and the coil does not change, inductance does not change either.

What happens is that with the press of the finger you bend the PCB boards that causes some changes.

Slight touch changes the total capacitance of the system which will also produce a response.

Hello,

thanks for your useful considerations. If I have to create the proper setup to use those buttons which is the best material and fixing system for that EVM board?

Which is the best configuration parameters?

Regards