Servo Motor Controlled Wireless Light Switch

Published by Device Plus Editorial Team at September 29, 2017

6. Servo-controlled light switch

For a practical example, I would like to make a device that automatically turns on the room light by pressing a light switch. I will combine Arduino + servo motor + 3D printer + Wi-Fi module to make it happen!

Note: the auto light switch we are about to make only works for a buttoned light switch system.

Let’s start by 3D printing the parts that will press the light switch button.

The servo motor used this time is MG996R, which has a stronger torque than the one used in the previous series. This servo motor has a torque of 9.4 kg and an operating voltage of 4.8 – 6.6 V. We’ll also be using ESP-WROOM-02 Wifi and try to operate the switch by moving the servo motor from PC or smartphone.

Figure 9. Parts for pressing switches

Figure 10. Outputting with 3D printer

Figure 11. Room switch

Figure 12. Installation of 3D parts on servo motor

Figure 13. Mounting on the room light switch

I used a strip tape to attach the device to the light switch.

Figure 14. Strip tape

When you are done, test to see if the servo motor works correctly and it turns on the light.

Does it work? Good! So as you’ve already realized, the switch that we just made can only turn on the light. This type of switch cannot, unfortunately, turn the light off and also turn the light back on. I want our switch to be able to press both ends so that it can be turned on and off automatically.

Figure 15. Measuring switch size

Let’s measure the width of the room light switch. It’s about 4 cm for my switch. I thought it would be better to create protruding parts onto the supporter part to press the light switch button on both sides. So, I 3D printed the parts as shown below.

Figure 16. Parts that can press both ends of switch button

Figure 17. Mounting onto servo motor

Once it’s mounted onto the servo motor, we will write a program to ESP-WROOM-02 so that we can operate the switch remotely.

Figure 18. Final remote light switch setup

7. Remote operation of the light switch

This mechanical system is connected to the wireless router installed in the room, and based on the acquired IP address, we can provide a function that can operate the servo motor.

When ESP-WROOM-02 is powered on, we can set up a reporting server to hit the external API for relaying the acquired IP address by e-mail after getting the IP address from the wireless router.

#include &amp;lt;ESP8266WiFi.h&amp;gt;
#include &amp;lt;Servo.h&amp;gt; 
 
const char *ssid = "[wifi_ssid]";
const char *password = "[wifi_password]";
 
//IP report server configuration
const char* host = "xxxx.xx.xxx";
String url = "/xxxx/";
  
Servo myservo;
Servo myservo2;
 
WiFiServer server(80);
 
String IpAddress2String(const IPAddress&amp;amp; ipAddress)
{
 return String(ipAddress[0]) + String(".") +\
 String(ipAddress[1]) + String(".") +\
 String(ipAddress[2]) + String(".") +\
 String(ipAddress[3]) ; 
}
  
void setup() {
 Serial.begin(115200);
 delay(10);
  
 Serial.println("Start!");
 Serial.println();
 Serial.print("Connecting to ");
 Serial.println(ssid);
  
 WiFi.begin(ssid, password);
  
 while (WiFi.status() != WL_CONNECTED) {
 delay(1500);
 Serial.print(".");
 }
 Serial.println("");
 Serial.println("WiFi connected");
  
 server.begin();
 Serial.println("Server started");
 Serial.println(WiFi.localIP());
 
//*********************************************************
// IP address notification
//*********************************************************
 WiFiClient client;
 const int httpPort = 80;
 if (!client.connect(host, httpPort)) {
 Serial.println("connection failed");
 return;
 }
  
 url += IpAddress2String(WiFi.localIP());
 client.print(String("GET ") + url + " HTTP/1.1\r\n" +
 "Host: " + host + "\r\n" + "Connection: close\r\n\r\n");
 delay(1000);
 Serial.print("Connecting url to ");
 Serial.println(url);
 
//*********************************************************************
 
}
  
void loop() {
 WiFiClient client = server.available();
 if (!client) {
 return;
 }
  
 Serial.println("new client");
 while(!client.available()){
 delay(1);
 }
  
 String req = client.readStringUntil('\r');
 Serial.println(req);
 client.flush();
 
 // Match the request
 int selectServo = 0;
 
int posSlash0 = req.indexOf("/");
String tmp = req.substring(0,posSlash0);
int posSlash1st = req.indexOf("/",1+posSlash0);
String action = req.substring(1+posSlash0,posSlash1st);
int posSlash2nd = req.indexOf("/",1+posSlash1st);
String sel = req.substring(1+posSlash1st,posSlash2nd);
int posSlash3rd = req.indexOf("/",1+posSlash2nd);
String valueTmp = req.substring(1+posSlash2nd,posSlash3rd);
int posSpace = valueTmp.indexOf(" ");
String value = valueTmp.substring(0,posSpace);
 
if(action == "favicon.ico HTTP"){
 return;
}
//GET /servo/1/60 HTTP/1.1
 
Serial.print("POS:");
Serial.print(posSlash1st);
Serial.print(":");
Serial.print(posSlash2nd);
Serial.print(":");
Serial.println(posSlash3rd);
 
Serial.print("ACTION:");
Serial.println(action);
Serial.print("SELECT SERVO:");
Serial.println(sel);
Serial.print("VALUE:");
Serial.println(value);
 
if(sel == "0"){
myservo.write(value.toInt());
}
 
  
 client.flush();
  
 String s = "HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\n&amp;lt;!DOCTYPE HTML&amp;gt;\r\n&amp;lt;html&amp;gt;";
 s += "&amp;lt;head&amp;gt;&amp;lt;meta name='viewport' content='width=device-width, initial-scale=1'&amp;gt;";
 s += "&amp;lt;link href='https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css' rel='stylesheet' media='screen'&amp;gt;"; 
 s += "&amp;lt;script type='text/javascript' src='https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js'&amp;gt;&amp;lt;/script&amp;gt;";
 s += "&amp;lt;/head&amp;gt;&amp;lt;body&amp;gt;";
 s += "\r\nSERVO ";
 s += sel;
 s += " is ";
 s += String(value);
 s += "&amp;lt;div class='container'&amp;gt;&amp;lt;div class='row'&amp;gt;";
 s += "&amp;lt;div class='col-md-12'&amp;gt;&amp;lt;h3&amp;gt;Servo0&amp;lt;/h3&amp;gt;&amp;lt;/div&amp;gt;";
 s += "&amp;lt;div class='col-md-12'&amp;gt;&amp;lt;a class='btn btn-primary' href='/servo/0/0'&amp;gt;ON&amp;lt;/a&amp;gt;&amp;lt;/div&amp;gt;\n";
 s += "&amp;lt;div class='col-md-12'&amp;gt;&amp;lt;a class='btn btn-info' href='/servo/0/50'&amp;gt;OFF&amp;lt;/a&amp;gt;&amp;lt;/div&amp;gt;\n";
s += "&amp;lt;div class='col-md-12'&amp;gt;&amp;lt;a class='btn btn-info' href='/servo/0/30'&amp;gt;STAY&amp;lt;/a&amp;gt;&amp;lt;/div&amp;gt;\n";
s += "&amp;lt;/div&amp;gt;&amp;lt;/div&amp;gt;";
 s += "&amp;lt;/body&amp;gt;";
 s += "&amp;lt;/html&amp;gt;\n";
  
 client.print(s);
 delay(1);
 Serial.println("Client disonnected");
}

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#include &lt;ESP8266WiFi.h&gt;

#include &lt;Servo.h&gt;

const char *ssid = "[wifi_ssid]";

const char *password = "[wifi_password]";

//IP report server configuration

const char* host = "xxxx.xx.xxx";

String url = "/xxxx/";

Servo myservo;

Servo myservo2;

WiFiServer server(80);

String IpAddress2String(const IPAddress&amp; ipAddress)

{

return String(ipAddress[0]) + String(".") +\

String(ipAddress[1]) + String(".") +\

String(ipAddress[2]) + String(".") +\

String(ipAddress[3]) ;

}

void setup() {

Serial.begin(115200);

delay(10);

Serial.println("Start!");

Serial.println();

Serial.print("Connecting to ");

Serial.println(ssid);

WiFi.begin(ssid, password);

while (WiFi.status() != WL_CONNECTED) {

delay(1500);

Serial.print(".");

}

Serial.println("");

Serial.println("WiFi connected");

server.begin();

Serial.println("Server started");

Serial.println(WiFi.localIP());

//*********************************************************

// IP address notification

//*********************************************************

WiFiClient client;

const int httpPort = 80;

if (!client.connect(host, httpPort)) {

Serial.println("connection failed");

return;

}

url += IpAddress2String(WiFi.localIP());

client.print(String("GET ") + url + " HTTP/1.1\r\n" +

"Host: " + host + "\r\n" + "Connection: close\r\n\r\n");

delay(1000);

Serial.print("Connecting url to ");

Serial.println(url);

//*********************************************************************

}

void loop() {

WiFiClient client = server.available();

if (!client) {

return;

}

Serial.println("new client");

while(!client.available()){

delay(1);

}

String req = client.readStringUntil('\r');

Serial.println(req);

client.flush();

// Match the request

int selectServo = 0;

int posSlash0 = req.indexOf("/");

String tmp = req.substring(0,posSlash0);

int posSlash1st = req.indexOf("/",1+posSlash0);

String action = req.substring(1+posSlash0,posSlash1st);

int posSlash2nd = req.indexOf("/",1+posSlash1st);

String sel = req.substring(1+posSlash1st,posSlash2nd);

int posSlash3rd = req.indexOf("/",1+posSlash2nd);

String valueTmp = req.substring(1+posSlash2nd,posSlash3rd);

int posSpace = valueTmp.indexOf(" ");

String value = valueTmp.substring(0,posSpace);

if(action == "favicon.ico HTTP"){

return;

}

//GET /servo/1/60 HTTP/1.1

Serial.print("POS:");

Serial.print(posSlash1st);

Serial.print(":");

Serial.print(posSlash2nd);

Serial.print(":");

Serial.println(posSlash3rd);

Serial.print("ACTION:");

Serial.println(action);

Serial.print("SELECT SERVO:");

Serial.println(sel);

Serial.print("VALUE:");

Serial.println(value);

if(sel == "0"){

myservo.write(value.toInt());

}

client.flush();

String s = "HTTP/1.1 200 OK\r\nContent-Type: text/html\r\n\r\n&lt;!DOCTYPE HTML&gt;\r\n&lt;html&gt;";

s += "&lt;head&gt;&lt;meta name='viewport' content='width=device-width, initial-scale=1'&gt;";

s += "&lt;link href='https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css' rel='stylesheet' media='screen'&gt;";

s += "&lt;script type='text/javascript' src='https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js'&gt;&lt;/script&gt;";

s += "&lt;/head&gt;&lt;body&gt;";

s += "\r\nSERVO ";

s += sel;

s += " is ";

s += String(value);

s += "&lt;div class='container'&gt;&lt;div class='row'&gt;";

s += "&lt;div class='col-md-12'&gt;&lt;h3&gt;Servo0&lt;/h3&gt;&lt;/div&gt;";

s += "&lt;div class='col-md-12'&gt;&lt;a class='btn btn-primary' href='/servo/0/0'&gt;ON&lt;/a&gt;&lt;/div&gt;\n";

s += "&lt;div class='col-md-12'&gt;&lt;a class='btn btn-info' href='/servo/0/50'&gt;OFF&lt;/a&gt;&lt;/div&gt;\n";

s += "&lt;div class='col-md-12'&gt;&lt;a class='btn btn-info' href='/servo/0/30'&gt;STAY&lt;/a&gt;&lt;/div&gt;\n";

s += "&lt;/div&gt;&lt;/div&gt;";

s += "&lt;/body&gt;";

s += "&lt;/html&gt;\n";

client.print(s);

delay(1);

Serial.println("Client disonnected");

}

As shown in the video above, I was able to switch the light ON / OFF from my PC.

Today we created a servo-controlled light switch that can be controlled wirelessly and remotely. There are many uses for these type of devices. Next time, we’re going to get a little more creative and combine multiple servo motors to make a camera stabilizer or gimbal. So stay tuned!

diy wireless light switch