Keyestudio ESP32 Manual page 91

ESP32 Starter Kit
8.5.14 Project 13: Mini Lamp
1. Description
In this project, we are going to control a lamp via Arduino UNO and a button. When we press the button, the state of
the lamp will shift(ON or OFF).
2. Working Principle
When the button is released, a voltage VCC passing through R29 provides a high level for S terminal. When pressed,
pin 1 and 3, pin 2 and 4 are connected and voltage on S1 arrives GND as a low level. At this moment, R29 avoids a
short circuit between VCC and GND.
8.5. Arduino Project 87