Week 5

This week we finally create the sensor. Tiberio and Tapio draw it: it consist of two conductive lines very close together which will work as a capacitor. After printing to a transparent substrate we expose the PCB with UV light and we proceed to etching process. Here are some pictures of the process:

Exposing
Exposing
etching
etching

Once we have the sensor ready is time to test it.

Finished sensor with resistor
Finished sensor with resistor

We use the oscilloscope and a square wave generator and then we measure the time constant to get the capacitance upon the law tau=RC. Using the built in function to know the rise time (from 10% to 90%) we can calculate the tau knowing rise_time=2.2tau.

Only sensor
Only sensor
Sensor with wet paper on it
Sensor with wet paper on it