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How to turn your computer on and off remotely

I needed to add the the ability to remotely turn my computer On or Off, and even hit the Reset button.

In this video, I explore how to control the Power and Reset buttons via WiFi with the help of a Wemos D1 Mini (similar to an Arduino) and some optocouplers, and an app for my phone.

Parts List:

    Wiring Diagram

    (click to enlarge)

    Commands you can send via WiFi

    Basic Commands:

    Turn On: on

    Turn Off: off

    Reset: reset

    Get Status: status

    Force Computer Off (keeps power button pressed for 10 seconds): forceOff

    Advanced commands:

    Press Power Button (stays pressed until you send a release command): pressPwr

    Release Power Button: releasePwr

    Case LED always on: lightOn

    Case LED always off: lightOff

    Case LED auto on or off: lightAuto

    Code
    #include <ESP8266WiFi.h>
    

    const char* ssid = <YOUR WIFI NAME>;
    const char* password = <YOUR WIFI PASSWORD>;
    const char ON = '+', 
     OFF = '-',
     SLEEP = '/',
     AUTO = 'A';
    

    const int pinPowerLightOut = D1,
     pinPowerLightIn = D5,
     pinPowerButton = D6,
     pinResetButton = D7,
    

     buttonPressTime = 250;
    

    char currentStatus = OFF;
    char lightStatus = AUTO;
    

    unsigned long autoDisconnectTime = 0,
     powerButtonReleaseTime = 0;
    

    WiFiServer wifiServer(80);
    WiFiClient client;
    

    unsigned long lastOn = 0,
     lastOff = 0;
    

    void changeStatusTo(char newStatus)
    {
     if(newStatus != currentStatus)
     {
     Serial.print("Status changed to ");
     Serial.println(newStatus); 
    

     } 
     currentStatus = newStatus;
    }
    

    void recordLightStatusChange(bool lightIn)
    {
     if(lightIn)
     lastOn = millis();
     else
     lastOff = millis();
    

    if(lightStatus == AUTO);
     digitalWrite(pinPowerLightOut, lightIn);
    

    }
    void statusChange()
    {
     bool currentLightStatus = !digitalRead(pinPowerLightIn);
    

    if(lastOn != 0 && lastOff != 0)
     {
     if((millis() < lastOn + 4000) && (millis() < lastOff + 4000))
     {
     changeStatusTo(SLEEP);
     recordLightStatusChange(currentLightStatus);
     return;
     } 
     }
    

    if(currentLightStatus)
     changeStatusTo(ON);
     else
     changeStatusTo(OFF); 
    

     recordLightStatusChange(currentLightStatus);
    }
    

    void Print(String toPrint)
    {
     client.print(toPrint);
     Serial.print(toPrint);
    }
    void Println(String toPrint)
    {
     client.println(toPrint);
     Serial.println(toPrint);
    }
    

    void processCommand(String command)
    {
     Serial.print(F("Received command "));
     Serial.println(command);
    

    if(command.equalsIgnoreCase(F("status")))
     {
     Print("Status: ");
     if(currentStatus == ON)
     Println("On");
     else if(currentStatus == OFF)
     Println("Off");
     else if(currentStatus == SLEEP)
     Println("Sleeping");
     }
     else if(command.equalsIgnoreCase(F("on")))
     {
     if(currentStatus != ON)
     {
     Println("Power Button Pressed (powering on)");
     pressPowerButton(buttonPressTime);
     }
     else
     Println("Machine is already on (button not pressed)");
    

    }
     else if(command.equalsIgnoreCase(F("off")))
     {
     if(currentStatus == ON)
     {
     Println("Power Button Pressed (powering off)");
     pressPowerButton(buttonPressTime);
     }
     else
     Println("Machine is already off (button not pressed)");
    

    }
     else if(command.equalsIgnoreCase(F("reset")))
     {
     unsigned long releaseTime = millis() + 500;
     digitalWrite(pinResetButton, HIGH);
     while(millis() < releaseTime)
     {}
     digitalWrite(pinResetButton, LOW);
    

    Println("Reset Button Pressed");
     }
     else if(command.equalsIgnoreCase(F("force off")))
     {
     if(currentStatus != OFF)
     {
     Print("Holding Power Button for 10 seconds...");
     pressPowerButton(10000);
     }
     }
     else if(command.equalsIgnoreCase(F("pressPwr")))
     {
     digitalWrite(pinPowerButton, HIGH);
     Println("Power Button Pressed");
     }
     else if(command.equalsIgnoreCase(F("releasePwr")))
     {
     digitalWrite(pinPowerButton, LOW);
     Println("Power Button Released");
     }
     else if(command.equalsIgnoreCase(F("light on")))
     {
     setLightStatus(ON);
     }
     else if(command.equalsIgnoreCase(F("light off")))
     {
     setLightStatus(OFF);
     }
     else if(command.equalsIgnoreCase(F("light auto")))
     {
     setLightStatus(AUTO);
     }
    }
    

    void setLightStatus(char newStatus)
    {
     if(newStatus == ON)
     {
     digitalWrite(pinPowerLightOut, HIGH);
     Println("Light On");
     return; 
     }
    

     if(newStatus == OFF)
     {
     digitalWrite(pinPowerLightOut, LOW);
     Println("Light Off"); 
     return;
     }
    

     if(newStatus == AUTO)
     {
     Println("Light Set to Auto"); 
     setLightStatus(currentStatus);
     }
    

    }
    

    void pressPowerButton(int duration)
    {
     powerButtonReleaseTime = millis() + (duration);
     digitalWrite(pinPowerButton, HIGH);
    }
    

    void runRoutineChecks()
    {
     checkIfPowerNeedsToRelease();
    

    if((millis() > lastOn + 4000) && (millis() > lastOff + 4000))
     statusChange();
    }
    

    void checkIfPowerNeedsToRelease()
    {
     if(powerButtonReleaseTime != 0)
     {
     if(millis() >= powerButtonReleaseTime)
     {
     digitalWrite(pinPowerButton, LOW);
     powerButtonReleaseTime = 0;
     Println("Power Button Released");
     } 
     }
    }
    

    /////////////----------------------------------------------------------------------------
    

    void setup() {
     Serial.begin(115200); 
     pinMode(pinPowerLightIn, INPUT_PULLUP);
     pinMode(pinPowerLightOut, OUTPUT);
     pinMode(pinPowerButton, OUTPUT);
     pinMode(pinResetButton, OUTPUT);
    

     attachInterrupt(digitalPinToInterrupt(pinPowerLightIn), statusChange, CHANGE);
    

     WiFi.begin(ssid, password);
    

    while (WiFi.status() != WL_CONNECTED)
     {
     delay(1000);
     Serial.println("Connecting..");
     }
    

    Serial.print("Connected to WiFi. IP:");
     Serial.println(WiFi.localIP());
    

     wifiServer.begin();
    }
    

    ///////////////////////////////////////////////////////////////////////////////////////////////////
    

    void loop()
    { 
    

     runRoutineChecks();
    

     client = wifiServer.available();
     if (client)
     {
     while (client.connected())
     {
     String comm = ""; 
     while (client.available()>0)
     {
     char c = client.read();
    

    autoDisconnectTime = millis() + 60000;
    

     if(c == ';')
     {
     processCommand(comm);
     comm = "";
     }
     else
     {
     comm.concat(c);
     }
     }
     runRoutineChecks();
     if(autoDisconnectTime > 1000 && millis() > autoDisconnectTime)
     {
     Serial.println("Client timeout"); 
     client.stop();
     }
     }
     client.stop();
     Serial.println("Client disconnected");
     autoDisconnectTime = 0; 
     }
    }