# Week 8
## Input Devices
### Group Assignment
> Probe an input device's analog levels and digital signals
For the group assignment we learned to use the oscilloscope to measure a binary signal comming from the output pin of a raspberri pi.
We learned about functionality that can actually decode the digital signal from bits into characters, as well as how to zoom in and out to observe any analogue signal.
|  |  |
|:---------:|:---------:|
| *The oscilloscope* | *Connecting the probes of the oscilloscope to the digital output pins* |
We saw how even a digital signal has tiny oscilations in the change of voltage.
### Individual Assignment
> Measure something: add a sensor to a microcontroller board that you have designed and read it.
### Design background
I want to make a sampler that inputs sound and plays it back as taps. Notably it should be able to have this type of gesture where you can create a drum roll with the edge of the table between two fingers:
### Capacitive Touch Sensor
I used the capacitance sensor for the sample pad I am creating for my final project.
I started with Quentin's code for the touch sensors. [Quentin Bolsee Test-Touch-RP2040](https://gitlab.cba.mit.edu/quentinbolsee/qpad-xiao/-/tree/main/code/Arduino/test_touch_RP2040?ref_type=heads).
I then needed to modify it to the pins that the sample pad is using.
To see which pins my pad is using, here is the schematic of the sample pad. I refered to Week 5 electronics design for the diagram of the Seed XIAO layout. In this case they are pins `26, 27, 28, 29, 6, 7`
|  |
|:---------:|
| *The schematic of the sample pad* |
I modified the touch test code to work for my controller, and was able to view the results by clicking on the serial monitor icon top right of Arduino IDE.
I was also able to measure the inputs from these sensors uing the built in Serial Plotter.
## Attachments
[Sample Pad Mk 1 KiCad Files](files/Sample-Pad-Mk-1)
[sample-pad-test-touch.ino](files/sample-pad-test-touch.ino)
## Acknowledgments