![\"ESP8266](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2020\/03\/ESP8266-NodeMCU-Read-Inputs-Control-Outputs-Arduino-IDE.jpg?resize=1024%2C576&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n\nPrerequisites<\/h2>\n\n\n\n
We’ll program the ESP8266 using Arduino IDE. So, make sure you have the ESP8266 boards add-on installed before proceeding:<\/p>\n\n\n\n
- Installing ESP8266 Board in Arduino IDE (Windows, Mac OS X, Linux)<\/a><\/li><\/ul>\n\n\n\n
ESP8266 NodeMCU Control Digital Outputs<\/h2>\n\n\n\n
First you need set the GPIO you want to control as an OUTPUT<\/span>. Use the pinMode()<\/span> function as follows:<\/p>\n\n\n\n
pinMode(GPIO, OUTPUT);<\/code><\/pre>\n\n\n\nTo control a digital output you just need to use the digitalWrite()<\/span> function, that accepts as arguments, the GPIO (int number) you are referring to, and the state, either HIGH<\/span> or LOW<\/span>.<\/p>\n\n\n\n
digitalWrite(GPIO, STATE);<\/code><\/pre>\n\n\n\nTake a look at the ESP8266 GPIO Reference Guide<\/a> to learn which GPIOs are more suitable to use as outputs.<\/p>\n\n\n\n
ESP8266 NodeMCU Read Digital Inputs<\/h2>\n\n\n\n
First, set the GPIO you want to read as INPUT<\/span>, using the pinMode()<\/span> function as follows:<\/p>\n\n\n\n
pinMode(GPIO, INPUT);<\/code><\/pre>\n\n\n\nTo read a digital input, like a button, you use the digitalRead()<\/span> function, that accepts as argument, the GPIO (int number) you are referring to.<\/p>\n\n\n\n
digitalRead(GPIO);<\/code><\/pre>\n\n\n\nTake a look at the ESP8266 GPIO Reference Guide<\/a> to learn which GPIOs are more suitable to use as inputs.<\/p>\n\n\n\n
Project Example<\/h2>\n\n\n\n
To show you how to use digital inputs and digital outputs, we\u2019ll build a simple project example with a pushbutton and an LED. We\u2019ll read the state of the pushbutton and light up the LED accordingly as illustrated in the following figure.<\/p>\n\n\n\n
![\"ESP8266](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2018\/10\/led_pushbutton.png?resize=750%2C373&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n\nSchematic Diagram<\/h2>\n\n\n\n
Before proceeding, you need to assemble a circuit with an LED and a pushbutton. We\u2019ll connect the LED to GPIO 5<\/span> (D1) and the pushbutton to GPIO 4<\/span> (D2).<\/p>\n\n\n\n
Parts Required<\/h3>\n\n\n\n
Here\u2019s a list of the parts to you need to build the circuit:<\/p>\n\n\n\n
- ESP8266 <\/a>(read Best ESP8266 Dev Boards<\/a>)<\/li>
- 5 mm LED<\/a><\/li>
- 330 Ohm resistor<\/a><\/li>
- Pushbutton<\/a><\/li>
- 10k Ohm resistor<\/a><\/li>
- Breadboard<\/a><\/li>
- Jumper wires<\/a><\/li><\/ul>\n\n\n
You can use the preceding links or go directly to MakerAdvisor.com\/tools<\/a> to find all the parts for your projects at the best price!<\/p>
![](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2017\/10\/header-200.png?w=1200&quality=100&strip=all&ssl=1\")
<\/a><\/p>\n\n\n\n![\"ESP8266](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2019\/04\/led_button_esp8266_bb.png?resize=1038%2C573&quality=100&strip=all&ssl=1\")
<\/a><\/figure><\/div>\n\n\n\nCode<\/h2>\n\n\n\n
Copy the following code to your Arduino IDE.<\/p>\n\n\n
\/\/ Complete Instructions: https:\/\/RandomNerdTutorials.com\/esp8266-nodemcu-digital-inputs-outputs-arduino\/\n\n\/\/ set pin numbers\nconst int buttonPin = 4; \/\/ the number of the pushbutton pin\nconst int ledPin = 5; \/\/ the number of the LED pin\n\n\/\/ variable for storing the pushbutton status\nint buttonState = 0;\n\nvoid setup() {\n \/\/ initialize the pushbutton pin as an input\n pinMode(buttonPin, INPUT);\n \/\/ initialize the LED pin as an output\n pinMode(ledPin, OUTPUT);\n}\n\nvoid loop() {\n \/\/ read the state of the pushbutton value\n buttonState = digitalRead(buttonPin);\n \/\/ check if the pushbutton is pressed.\n \/\/ if it is, the buttonState is HIGH\n if (buttonState == HIGH) {\n \/\/ turn LED on\n digitalWrite(ledPin, HIGH);\n } else {\n \/\/ turn LED off\n digitalWrite(ledPin, LOW);\n }\n}\n<\/code><\/pre>\n\tView raw code<\/a><\/p>\n\n\n\n
How the Code Works<\/h2>\n\n\n\n
In the following two lines, you create variables to assign pins:<\/p>\n\n\n\n
const int buttonPin = 4;\nconst int ledPin = 5;<\/code><\/pre>\n\n\n\nThe button is connected to GPIO 4<\/span> and the LED is connected to GPIO 5<\/span>. When using the Arduino IDE with the ESP8266, 4 corresponds to GPIO 4<\/span> and 5 corresponds to GPIO 5<\/span>.<\/p>\n\n\n\n
Next, you create a variable to hold the button state. By default, it’s 0 (not pressed).<\/p>\n\n\n\n
int buttonState = 0;<\/code><\/pre>\n\n\n\nIn the setup()<\/span>, you initialize the button as an INPUT<\/span>, and the LED as an OUTPUT<\/span>. For that, you use the pinMode()<\/span> function that accepts the pin you are referring to, and the mode: INPUT<\/span> or OUTPUT<\/span>.<\/p>\n\n\n\n
pinMode(buttonPin, INPUT);\npinMode(ledPin, OUTPUT);<\/code><\/pre>\n\n\n\nIn the loop()<\/span> is where you read the button state and set the LED accordingly.<\/p>\n\n\n\n
In the next line, you read the button state and save it in the buttonState<\/span> variable. As we\u2019ve seen previously, you use the digitalRead()<\/span> function.<\/p>\n\n\n\n
buttonState = digitalRead(buttonPin);<\/code><\/pre>\n\n\n\nThe following if statement, checks whether the button state is HIGH<\/span>. If it is, it turns the LED on using the digitalWrite()<\/span> function that accepts as argument the ledPin<\/span>, and the state HIGH<\/span>.<\/p>\n\n\n\n
if (buttonState == HIGH) {\n digitalWrite(ledPin, HIGH);\n}<\/code><\/pre>\n\n\n\nIf the button state is not HIGH<\/span>, you set the LED off. Just set LOW<\/span> as a second argument to in the digitalWrite()<\/span> function.<\/p>\n\n\n\n
else {\n digitalWrite(ledPin, LOW);\n}<\/code><\/pre>\n\n\n\nUploading the Code<\/h2>\n\n\n\n
Before clicking the upload button, go to Tools<\/strong> > Board<\/strong>, and select the board you\u2019re using. In my case, it\u2019s the NodeMCU 1.0 (ESP-12 E Module)<\/a>. If you don’t know your ESP8266 model, you can select “Generic ESP8266 Module”.<\/p>\n\n\n\n
Go to Tools <\/strong>> Port <\/strong>and select the COM port the ESP8266 is connected to. Then, press the upload button and wait for the \u201cDone uploading<\/strong>\u201d message. <\/p>\n\n\n\n
Demonstration<\/h2>\n\n\n\n
After uploading the code, test your circuit. Your LED should light up when you press the pushbutton:<\/p>\n\n\n\n
![\"ESP8266](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2020\/03\/ESP8266-NodeMCU-Input-Output-Button-Pressed-LED-On-Arduino-IDE.jpg?resize=750%2C422&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n\nAnd turn off when you release it:<\/p>\n\n\n\n
![\"ESP8266](\"https:\/\/i0.wp.com\/randomnerdtutorials.com\/wp-content\/uploads\/2020\/03\/ESP8266-NodeMCU-Input-Output-Button-Not-Pressed-Arduino-IDE.jpg?resize=750%2C422&quality=100&strip=all&ssl=1\")
<\/figure><\/div>\n\n\n\nWrapping Up<\/h2>\n\n\n\n
With this getting started guide, you’ve learned how to read digital inputs and control digital outputs with the ESP8266 using Arduino IDE.<\/p>\n\n\n\n
If you want to learn how to read analog inputs, or output PWM signals, read the following guides:<\/p>\n\n\n\n
- ESP8266 ADC \u2013 Read Analog Values<\/a><\/li>
- ESP8266 PWM – Dim LED<\/a><\/li><\/ul>\n\n\n\n
You may also find useful taking a look at the ESP8266 GPIO Reference<\/a> that shows how to use the ESP8266 GPIOs and its functions.<\/p>\n\n\n\n
Finally, if you want to learn more about the ESP8266, take a look at our resources:<\/p>\n\n\n\n
- Home Automation using ESP8266<\/a><\/li>
- MicroPython Programming with ESP32\/ESP8266<\/a><\/li>
- More ESP8266 Projects…<\/a><\/li><\/ul>\n","protected":false},"excerpt":{"rendered":"
In this getting started guide you’ll learn how to read digital inputs like a button switch and control digital outputs like an LED using the ESP8266 NodeMCU board with Arduino … <\/p>\n
- MicroPython Programming with ESP32\/ESP8266<\/a><\/li>
- ESP8266 PWM – Dim LED<\/a><\/li><\/ul>\n\n\n\n
- 5 mm LED<\/a><\/li>
- ESP8266 <\/a>(read Best ESP8266 Dev Boards<\/a>)<\/li>