# Lecture notes Digital - Either 0 or 1 Analog - Read voltage rule of thumb for signal measuring. At least sample at double the frequency that is being sampled from the sensor. ![alt text](image.png) GPIO Low - 0 to 1/3 vcc High 2/3 to 1 vcc Signal from a DHT ![alt text](image-1.png) ![alt text](image-2.png) ![alt text](image-3.png) ds18b20 ![alt text](image-4.png) ![alt text](image-7.png)