This week, I planned to design a capacitive touch sensor, well, more of a touchpad, and decide if I want to use it in my final project.
Schematic
I started with making the schematic and board layout in Eagle..
Milling the board
I then milled my boards with the SRM-20 in the arch shop. The 1/64 end mill seemed to not cut so well. I ended up a board with bad traces. I checked the end mill and it looked perfectly fine under the microscope. Then, I was told that the sacrificial layer that holds the board may be uneven.
I checked and made sure it was all okay, and milled again. But it turned out not so good again.
So, now I decided to change the end mill. And, it seemed to work perfectly well!
Then I lined up all my components and soldered them..
This is what I had at the end of soldering all components..
But I wanted a touch pad.. So, I reconfigured it this way..
I then adapted my previous button and LED code to work for the touch sensing. I used Avrdude to flash the program on to the board. Here are some videos of the working touchpad..
I also made a temperature sensor for the interface programming week.. check that out here!