Lesson 3--Microduino "Button Controlled LED"

Language	English

Objective The first two lessons showed you how to use software to control the LED directly. If we add a button to control the LED light, then we can combine the use of both hardware and software. Previously, we used Microduino I/O port as the output to control the LED. So if want to use a button, how would we monitor the input signal of the button? In this lesson, we will use a button as an example to show how to use Microduino as the input. Equipment Microduino-Core Microduino-FT232R Other hardware equipment 1x Box of breadboard jumper wires 1x Breadboard 1x LED (Light-Emitting Diode) 1x 220ohm resistor 1x Button 1x USB Data cable Button Button principle Button connection Experiment Schematic Using external pulldown method, when unpressed, it is "LOW". When pressed, it is high. Program LED display button value const int buttonPin = 2; // Define button input pin const int ledPin = 11; //Define LED pin int buttonState = 0; //Initialize the button value void setup() { pinMode(ledPin, OUTPUT); //Set the LED pin as output pinMode(buttonPin, INPUT); //Set button pin as input } void loop(){ buttonState = digitalRead(buttonPin);//Read the value from the buttonPin if (buttonState == HIGH) { digitalWrite(ledPin, HIGH); //If the button input signal is high, the LED will light up } else { digitalWrite(ledPin, LOW); //LED goes out } } LED voltage flip const int buttonPin = 2; // Define button input pin const int ledPin = 11; int buttonState = 0; boolean led; //Define LED as boolean（true or false） void setup() { pinMode(ledPin, OUTPUT); // pinMode(buttonPin, INPUT); //Set the button pin as input pinMode(buttonPin, INPUT_PULLUP);//Set button pin as internal pull-up input } void loop(){ buttonState = digitalRead(buttonPin); if (buttonState ==HIGH) { delay(200); //Short time delay for stabilization // delay(1000); //Long time press // if (buttonState == LOW) //Check still is low led=!led; //LED state flip } digitalWrite(ledPin, led); } digitalRead(）usage Read a pin's value and return HIGH or LOW. Result Program 1：LED display input button value. High value will light the LED. Program 2：Each time you press the button, LED voltage will flip. Video