Gert helped us probe a motion sensor with an oscilloscope, and we saw different different frequencies at different pins.

I wanted to use step response to create a touch sensor, as I want to use a touch sensor for my final project. I went to Anthony’s office hours and would like to give him a huge thank you for explaining to me how step response works so I could create my board.

Step response works by a transmission pin sending alternating high and low signals. In this case the high signal is 3.3 V and the low signal is 0 V. Then the receiver pin measures what voltage it senses. This works using the principle of capacitance, as there is capacitance between the two plates, and what is measured is the change in capacitance. In my case, when the plate is touched the capacitance increases so the measured voltage is higher.

I designed my board in Kicad and milled it on the Roland SRM-20. At first, I did not convert the image to black and white when converting it from gerber to image and the software would not read the files. I had to reupload the images in black and white and then I was able to mill my board. During this trouble shooting, my origin ended up getting shifted and I just barely was able to cut my board on the copper. This is a warning to not get too excited when you figure out an issue, and make sure that you still did all the steps properly.

After milling my board, I soldered on the Xiao and the two resistors and was able to test my board. For the code, I used the code from Adrian Torres , a previous fab lab student and his file can be found here . His website also helpfully linked to this tutorial which helped me learn about step response. I tested my sensor and it worked (yay!).