Two-way Control with Web and Button

About the Application

You can expand the functionality of the prev app if you add a hardware button control. Pressing the button will also toggle the state of the GPIO line (LED, relay) which is reflected in the LED state displayed in the browser window.

GitHub Repository

• Name: tps-gpio-tutorials

• Repository page: https://github.com/tibbotech/tps-gpio-tutorials

• Clone URL: https://github.com/tibbotech/tps-gpio-tutorials.git

• Updated At: Mon Oct 10 2016

Node.js Application

Add the following code to server.js:

...  
var button = gpio.init("S11A");  
var wasButtonPressed = false;  
button.setDirection('input');  
setInterval(function(){     
            // If button is just released... 
            if(button.getValue() === 1 && wasButtonPressed === true){        
            wasButtonPressed = false;   
       
            // ...reads the LED state... 
            var ledState = led.getValue();
          
            //...inverses it... 
            if(ledState === 1){             
            ledState = 0         
            }else{            
                 ledState = 1;         
            }    
      
            //...writes...         
            led.setValue(ledState);         
            //...and submits to the web app if connected 
            if(clients !== undefined){             
                     clients.emit('tps:state:changed', ledState);         
            }     
         }else if(button.getValue() === 0){         
           // If button is pressed         
            wasButtonPressed = true;     
         } 
},100);  
...