User Manual

102
Lesson 20 Photoresistor Module
Introduction
A photoresistor is a light-controlled variable resistor. The resistance of a photoresistor
decreases with increasing incident light intensity.
Components
- 1 * Raspberry Pi
- 1 * Breadboard
- 4 * Jumper wires (Male to Male, 2 red and 2 black)
- 1 * Network cable (or USB wireless network adapter)
- 1 * PCF8591
- 1 * Photoresistor module
- 1 * 3-Pin anti-reverse cable
- Several Jumper wires (Male to Female)
Experimental Principle
With light intensity increasing, the resistance of a photoresistor will decrease. Thus the output
voltage changes. Analog signals collected by the photoresistor are converted to digital
signals through PCF8591. Then these digital signals are transmitted to Raspberry Pi and printed
on the screen. The schematic diagram: