Remote control extension cord

"Polarity"

The wide side of the plug and socket is neutral and is eventually connected to ground. In house wiring this wire is normally white.
The narrow side of the plug and socket is Hot and is 120 VAC or 240VAC with respect to ground. In house wiring this wire is normally black or red.
The third ground lead, the round connector is directly connected to ground. This wire is green.
Since we are only switching one of the two leads to turn the power on and off, switch the hot, black or red, lead to ensure when power is off that the remaining lead will not be 120 VAC with respect to ground. In other words - if I toss the socket shown in the above picture into the sink, it will probably be safe when it is off.

Current

ESP-01 and Relay Module
Ensure that your circuit will not draw more than the relay is rated for. I would be inclined to stay well below the maximum current. I would be wary of using these little relays to control a toaster.

If you don't have your esp-01 and relay in a container you may want to consider putting some black tape over the back of the relay board. There is 120VAC on the back solder connections when the extension cord is plugged in.

Simple Web Page to Control the extension cord

Examples of a light - off

and On

Front Lights Control

ESP01 and relay in electrical Box

Lights Off

Lights On

Programming

I use the Arduino IDE to program my ESPs

Since the ESP-01 board does not have built in USB port like the D1-Mini and
the ESP-12E Nodemcu we have to supply one to upload our code to the ESP.
The unit pictured does this. It is purpose built for the ESP-01 to plug into.
There are two modes selected by the shown switch:

PROG - to allow code to be uploaded and
UART to allow your running code to communicate via the USB interface.

To change modes the ESP-01 needs to be reset via unplugging and plugging
in the USB interface.

ESP-01 attached to the FTDI interface/programmer


// Board is Generic ESP8266 Module

//From: https://www.instructables.com/ESP0101S-RELAY-MODULE-TUTORIAL/
// Modified by Deid Reimer 2020-02-06

#include <esp8266wifi.h>



// Variables for debugging
int restartCount = 0;  // Number of times the wifi has been restarted.
int waitCount = 0;     // Number of seconds waiting for input

// Credentials
const char* ssid = "wifi";
const char* password = "password";

// The relay is connected to  GPIO0
#define RELAY 0

// Variables for wifi restart if wifi lost
unsigned long previousMillis = 0;
unsigned long interval = 30000;

// Current status of relay.  On boot set low.
int value = LOW;

// Define the server on port 80
WiFiServer server(80);

void setup() {
    // I set the serial monitor slow because I can't read faster so
    // what's the point ...
    Serial.begin(9600);

    // Set the relay for output and default off
    pinMode(RELAY, OUTPUT);
    digitalWrite(RELAY, value); 

    // Connect to the WiFi network
    Serial.println();
    Serial.println();
    Serial.print("Connecting to ");
    Serial.println(ssid);
    WiFi.begin(ssid, password);
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }
    Serial.println("");
    Serial.println("WiFi connected");

    // Set wifi restart and persistent
    WiFi.setAutoReconnect(true);
    WiFi.persistent(true);

    // Print the IP address
    Serial.print("Use this URL to connect: ");
    Serial.print(WiFi.localIP());
    Serial.println("/");

    // Start the web server
    server.begin();
    Serial.println("Server started");
}

void loop() {
    // Check if a client has connected delay and
    // restart the loop if not.
    WiFiClient client = server.available();
    if (!client) {
        //Serial.println("returning");
        delay(10);
        return;
    }

    // There is a connection, wait for the client to send a request
    // and count and restart loop if too long a wait.
    int j = 0;
    while (!client.available()) {
        delay(1000);
        Serial.println(j++);
        if (j > 10) {
            waitCount = j;
            client.flush();
            return;
        }
    }
    Serial.println("new client");

    // Read the first line of the request
    String request = client.readStringUntil('\r');
    Serial.println(request);
    // Trash anything else
    client.flush();

    // Is the reguest ON, HIGH.  Yes turn the relay on.
    if (request.indexOf("/RELAY=ON") != -1)  {
        Serial.println("RELAY=ON");
        digitalWrite(RELAY, HIGH);
        value = HIGH;
    }
    // Or of OFF turn the relay off
    if (request.indexOf("/RELAY=OFF") != -1) {
        Serial.println("RELAY=OFF");
        digitalWrite(RELAY, LOW);
        value = LOW;
    }

    // Return the response - web page.
    // http part
    client.println("HTTP/1.1 200 OK");
    client.println("Content-Type: text/html");

    //  this is a must. Separates http from html
    client.println("");

    // html part
    client.println("");
    client.println("");
    client.println("ESP8266 RELAY Control V1.0");
    client.println("");
    client.println("");
    client.print("Restarts: ");
    client.println(restartCount);
    client.print("waitCount: ");
    client.println(waitCount);
    client.println("");
    client.print("Relay is now: ");

    // clear wait for data count
    waitCount = 0;

    if (value == HIGH) {
        client.print("On");
    } else {
        client.print("Off");
    }

    client.println("");
    client.println("Turn OFF RELAY");
    client.println("Turn ON RELAY");
    client.println("");

    delay(1);
    Serial.println("Client disconnected");
    Serial.println("");

    // if WiFi is down, try reconnecting
    unsigned long currentMillis = millis();
    if ((WiFi.status() != WL_CONNECTED) && (currentMillis - previousMillis >= interval)) {
        Serial.print(millis());
        Serial.println("Reconnecting to WiFi...");
        WiFi.disconnect();
        WiFi.begin(ssid, password);
        previousMillis = currentMillis;
    
        //Alternatively, you can restart your board
        //ESP.restart();
    }
}

2022-02-07