Relay

Relay, also known as electrical relay, is an electronic control device, usually used in automatic control circuits, it is actually a kind of "automatic switch" that uses a smaller current to control a larger current. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit. You will need: Arduino Uno *11 relay module *1Breadboard *1LED *1100 ohm resistor *1Jumpers Wiring: Relay Arduino IN -> 3 VCC -> 5V GND -> GND Normally Open Port -> 4 Relay LED Common Port -> +   Sample Code: int sign= 3;int led= 4;void setup(){ pinMode(sign, OUTPUT); pinMode(led, OUTPUT);...