Touch sensor "Lollipop"

Just lollipop (bushi)
As for why it was made into a lollipop, it was entirely because I made the touch disc first and then when I was thinking about how to lay out the remaining components, I found that it could be made into a row. The length was adjusted to within 10cm and it could be directly white. Whoring PCB
verifies the solution of TTP226 touch sensor chip for ring touch panel.
Use DIP switches to set the sensitivity. The setting details are shown in the figure below (taken from the data sheet. If you want the lowest sensitivity, you can also directly connect all four pads above the switch. Use a jumper to connect to ground.
TTP226 data sheet: TTP226-809SN_(TONTEK)
(The line sequence is based on my logic analyzer. It is not guaranteed that
the logic analyzer can be used to see the circular movement trajectory of the finger on the ring and the corresponding level output timing, as shown below (I am using channels 0-8 )
You can also touch a single touch pad with your finger, and the corresponding indicator light will light up.
Other notes:
Do not update the PCB, and do not re-lay the copper, otherwise you will see a mess!
I laid the copper first with the keepout layer. "Mold" limits the scope of copper paving, otherwise circular and sector-shaped copper paving will be difficult to draw. It is best to delete the mold for copper paving, and then repair the border through arcs (obsessive-compulsive disorder), so it is easy to rebuild the copper paving without a mold. It'll be a mess.
I'll add more if I think of it.