ESP8266 / Hardware / IOT / nodemcu / PHP

ESP8266 Power Monitor

by htladmin · Published December 7, 2015 · Updated June 4, 2016

Energy Monitoring using ESP8266

Last month we have been using air-conditioning for more than usual. And when I received the bill, the bill was 46 USD but previously the bill never gone up above 20 USD. When analysed the bill and found there was a revision in the tariff. Here is the tariff.

All the tariffs were for the Bi-Monthly consumption.

Consumption	Slab	Charges Per Unit (USD)	Fixed Charges for 2 months
Upto 100 Units	0-100 units	0.016	0.31
Upto 200 Units	0-200 units	0.02	0.31
Upto 500 Units	0-200 units	0.03	0.47
	201-500 units	0.05	0.47
Above 500 Units	0-200 units	0.06	0.63
	201-500 units	0.07	0.63
	Above 501 units	0.10	0.63

All the tariffs were for the Bi-Monthly consumption I have consumed 630 Units of electricity for the month of April and May of 2015

So the calculation follows to tarrif Above 500 Units

200 * 0.06 = 12 USD

300 * 0.07 = 21 USD

130 * 0.10 = 13 USD

For Total 630 Units = 46 USD

If we use energy bellow 500 units for 60 days the bill would be

200 * 0.03 = 6 USD

299 * 0.05 = 14.95 USD

For 499 Units = 20.95 USD

Conceive of the Project

If we need to utlize energy bellow 499 units for Bi-monthly (60 days) we need to monitor the energy usage instantaniously and log the datas.

Materials laying around

1. Raspberry PI (I already had raspberry PI running rasbian for home automation)

2. ESP8266 (ESP-12)

3. L14G2 (Photo Transistor)

4. 2600Mah Power Bank

5. 5V Charger (For charging Power bank)

How.

I had a analogue old type meter with spinning wheel . With no LED’s or pulse output .

So I had to install a watt-hour meter with LED pulse output after the main meter. The newly installed meter has output of 3200 pulse per kilowatt (3200 Pulses/Unit) through Red color LED.

So the simple logic is to capture the pulse count for every 60 seconds from wathour meter LED with L14G2 Photo Transistor and update to the raspberry PI web-server on scheduled every minute through ESP8266 with interrupt and timer function.

In the web-server part Raspberry PI running rasbian with apache2, PHP and MySQL. have a simple PHP script to receive the values and save it to MySQL database. The script will be called by ESP8266 on every minute to post the collected pulses. Raspberry web-server script also has the reports for the usage of power.

Well, we have some backup policies in the ESP8266 and some Bugs.

When the connection with ESP8266 and Raspberry web-server was not established on the updated schedule due do any reasons, The logged pulse for the current minute will be accumulated to the next until the success full connection establishment and update.

The Bug is Interrupt was not working after 40-50 minutes of continues operation. So to overcome that the ESP8266 Programmed to reset every 30 minutes. (simple but efficient)

Here is the video of the project testing in progress with the computer processing LED istead of watthour LED

Attached the images

ESP8266 Stack with PowerBank

ESP8266 Stack with stack able board and pull down resistor connected to GPIO13

ESP8266 Stack with stacakble board and connector for L14G2

ESP8266 Stack with Power-bank and L14G2 wired

Installed the L14G2 with the masking tape facing the pulse output LED of watt-hour meter.

Cheap and neat enclosure from ESP Stack

Screwed the enclosure and powered the power-bank from the 5V mobile charger. and ESP Stack with output from power-bank

Reports Front Page

Logged Pulses and Watts from every minute

MinuteWise Pulses /Watts Consumed

DayWise Power Consumption Graph

Attached the images ESP8266 Stack with PowerBank

Access the live reports @ https://www.oakdock.com

Code of ESP8266 Stack (NodeMCU)

powermon.lua

gpio2 =7
count = 0
avg=0
watts=0
accu=1
loged = 0
print("Esp8266 Power Monitor\n")
function debounce (func)
    local last = 0
    local delay = 2000
    return function (...)
        local now = tmr.now()
        if now - last < delay then return end
        last = now
        return func(...)
    end
end


function resetnode() 
    node.reset()
    loged = 0
end

function upload() 
 conn = net.createConnection(net.TCP, 0) 
 conn:on("receive", 
  function(conn, payload) 
   success = true
   print(payload)
  end)  
 conn:on("disconnection", 
  function(conn, payload)
   print('\nDisconnected')
    if loged >= 60 then
    resetnode()
    end
  end)
 conn:on("connection", 
  function(conn, payload) 
   print('\nConnected') 
   conn:send("GET /putrows.php?"
   .."what=xxxxxxxx&devid=1&pulse="..count
   .."&power="..watts
   .." HTTP/1.1\r\n" 
   .."Host: oakdock.com\r\n" 
   .."Connection: keep-alive\r\n"
   .."Accept: */*\r\n" 
   .."User-Agent: Mozilla/4.0 (compatible; esp8266 Lua; Windows NT 5.1)\r\n" 
   .."\r\n")
 count=0
 avg=0
 watts=0
 accu=1
  end)  
 print("Opening port")
 accu = accu + 1
 loged = loged + 1
 print("Accu "..accu.."\n")
 conn:connect(80,'oakdock.com') 
end


function onChange ()
    count=count+1
    print("Int"..count.."\n")
end

gpio.mode(gpio2, gpio.INT)
gpio.trig(gpio2, 'up', debounce(onChange))

tmr.alarm(0,60000, 1, function()

if (count > 0 ) then
avg =  (accu * 60) / count
watts = (( 3600 / avg ) / 3200 ) * 1000
end
print("Count "..count.."\n")
print("Average "..avg.."\n")
print("Watts "..watts.."\n")
print("Accu "..accu.."\n")

upload()

 
 end)

gpio2 =7

count = 0

avg=0

watts=0

accu=1

loged = 0

print("Esp8266 Power Monitor\n")

function debounce (func)

local last = 0

local delay = 2000

return function (...)

local now = tmr.now()

if now - last < delay then return end

last = now

return func(...)

end

function resetnode()

node.reset()

loged = 0

end

function upload()

conn = net.createConnection(net.TCP, 0)

conn:on("receive",

function(conn, payload)

success = true

print(payload)

end)

conn:on("disconnection",

function(conn, payload)

print('\nDisconnected')

if loged >= 60 then

resetnode()

end

end)

conn:on("connection",

function(conn, payload)

print('\nConnected')

conn:send("GET /putrows.php?"

.."what=xxxxxxxx&devid=1&pulse="..count

.."&power="..watts

.." HTTP/1.1\r\n"

.."Host: oakdock.com\r\n"

.."Connection: keep-alive\r\n"

.."Accept: */*\r\n"

.."User-Agent: Mozilla/4.0 (compatible; esp8266 Lua; Windows NT 5.1)\r\n"

.."\r\n")

count=0

avg=0

watts=0

accu=1

end)

print("Opening port")

accu = accu + 1

loged = loged + 1

print("Accu "..accu.."\n")

conn:connect(80,'oakdock.com')

end

function onChange ()

count=count+1

print("Int"..count.."\n")

end

gpio.mode(gpio2, gpio.INT)

gpio.trig(gpio2, 'up', debounce(onChange))

tmr.alarm(0,60000, 1, function()

if (count > 0 ) then

avg = (accu * 60) / count

watts = (( 3600 / avg ) / 3200 ) * 1000

end

print("Count "..count.."\n")

print("Average "..avg.."\n")

print("Watts "..watts.."\n")

print("Accu "..accu.."\n")

upload()

end)

Note : xxxxxxxx is the secret code in your php script . and make sure to change oakdock.com to your raspberry IP

init.lua

wifi.setmode(wifi.STATION)
wifi.sta.config("user","pass")
wifi.sta.connect()
dofile ("powermon.lua")

wifi.setmode(wifi.STATION)

wifi.sta.config("user","pass")

wifi.sta.connect()

dofile ("powermon.lua")

Note : user and pass is your wifi credentials and make sure to change it.

PHP Code for Raspberry PI

putrows.php

<?php
include_once './DbConnect.php';

function putrows() {
//	echo $_GET["what"];
    if ($_GET["what"] == "xxxxxxxx") {

        $response = array();

        $devid = $_GET["devid"];
	$pulse = $_GET["pulse"];
	$power = $_GET["power"];

        $db = new DbConnect();

        $query = "INSERT INTO `powermon`.`powerlog` (`devid`, `logdate`, `pulsecount`, `watts`) VALUES ('$devid',now(),'$pulse','$power')";

        $result = mysql_query($query) or die(mysql_error());

        if ($result) {
            $response["error"] = false;
            $response["message"] = "OK";
        } else {
            $response["error"] = true;
            $response["message"] = "Failed";
        }

    } else {
        $response["error"] = true;
        $response["message"] = "Invalid Login!";
    }

    

    // echo json response

    echo json_encode($response);

}

putrows();

?>

<?php

include_once './DbConnect.php';

function putrows() {

// echo $_GET["what"];

if ($_GET["what"] == "xxxxxxxx") {

$response = array();

$devid = $_GET["devid"];

$pulse = $_GET["pulse"];

$power = $_GET["power"];

$db = new DbConnect();

$query = "INSERT INTO `powermon`.`powerlog` (`devid`, `logdate`, `pulsecount`, `watts`) VALUES ('$devid',now(),'$pulse','$power')";

$result = mysql_query($query) or die(mysql_error());

if ($result) {

$response["error"] = false;

$response["message"] = "OK";

} else {

$response["error"] = true;

$response["message"] = "Failed";

}

} else {

$response["error"] = true;

$response["message"] = "Invalid Login!";

}

// echo json response

echo json_encode($response);

}

putrows();

Note : xxxxxxxx is the secret code should match to the code in powermon.lua script

DbConnect.php

<?php
/**
 * Connecting / disconnecting Database
 *
 * @author Mohan
 */


class DbConnect {
    private $conn;
    // constructor
    function __construct() {
    // connecting to database
    $this->connect();
    }

    // destructor
    function __destruct() {
    // closing db connection
    $this->close();
    }


   /**
     * Establishing database connection
     * @return database handler
     */
    function connect() {        
        include_once dirname(__FILE__) . './Config.php';
    // Connecting to mysql database
    $this->conn = mysql_connect('localhost', 'user', 'pass') or die(mysql_error());
       // Selecting database
       mysql_select_db('powermon') or die(mysql_error());
       // returing connection resource
       return $this->conn;
    }

    /**
     * Closing database connection
     */

    function close() {
        // closing db connection
        mysql_close($this->conn);
    }

}

?>

<?php

/**

* Connecting / disconnecting Database

* @author Mohan

class DbConnect {

private $conn;

// constructor

function __construct() {

// connecting to database

$this->connect();

}

// destructor

function __destruct() {

// closing db connection

$this->close();

}

/**

* Establishing database connection

* @return database handler

function connect() {

include_once dirname(__FILE__) . './Config.php';

// Connecting to mysql database

$this->conn = mysql_connect('localhost', 'user', 'pass') or die(mysql_error());

// Selecting database

mysql_select_db('powermon') or die(mysql_error());

// returing connection resource

return $this->conn;

}

/**

* Closing database connection

function close() {

// closing db connection

mysql_close($this->conn);

}

Note : user and pass is the login details for the mysql database server the database name we used is powermon

getdata.php

<?php
include_once './DbConnect.php';

function ShowLogs(){
    $db = new DbConnect();
    $response = array();
    $response["pmon"] = array();

    $result = mysql_query("SELECT * FROM powerlog order by logdate DESC limit 60");
   
    while($row = mysql_fetch_array($result)){
echo $row['logdate'] . ' | ' . $row['pulsecount'] . ' Pulse | ' .$row['watts'] . " Watts<br>";
    }

}

ShowLogs();
?>

<?php

include_once './DbConnect.php';

function ShowLogs(){

$db = new DbConnect();

$response = array();

$response["pmon"] = array();

$result = mysql_query("SELECT * FROM powerlog order by logdate DESC limit 60");

while($row = mysql_fetch_array($result)){

echo $row['logdate'] . ' | ' . $row['pulsecount'] . ' Pulse | ' .$row['watts'] . " Watts<br>";

}

ShowLogs();

Note :These files should be on the Raspberry Pi Server var//www/ Directory

SQL Structure

Database name : powermon

Table name : powerlog

Field name	Type	Allow nulls?	Key	Default value	Extras
id	int(11)	No	Primary	NULL	auto_increment
devid	int(11)	No	None	0
logdate	datetime	No	None	NULL
pulsecount	int(11)	No	None	0
watts	float	No	None	0

Create table script.

--
-- Database: `powermon`
--

-- --------------------------------------------------------

--
-- Table structure for table `powerlog`
--

CREATE TABLE IF NOT EXISTS `powerlog` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `devid` int(11) NOT NULL DEFAULT '0' COMMENT 'Device ID',
  `logdate` datetime NOT NULL,
  `pulsecount` int(11) NOT NULL DEFAULT '0',
  `watts` float NOT NULL DEFAULT '0' COMMENT 'Watts',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;

-- Database: `powermon`

-- --------------------------------------------------------

-- Table structure for table `powerlog`

CREATE TABLE IF NOT EXISTS `powerlog` (

`id` int(11) NOT NULL AUTO_INCREMENT,

`devid` int(11) NOT NULL DEFAULT '0' COMMENT 'Device ID',

`logdate` datetime NOT NULL,

`pulsecount` int(11) NOT NULL DEFAULT '0',

`watts` float NOT NULL DEFAULT '0' COMMENT 'Watts',

PRIMARY KEY (`id`)

) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;

If everything is correctly configured you can see the powerlog table filled with new low on every minute. from the esp8266.

and you can make your own reports from the data available. and charts can be done using amcharts.

Happy coding..

Tags: esp8266 esp8266 iot esp8266 power monitor nodemcu nodemcu power monitor tinycpu

ESP8266 Power Monitor

You may also like...

Products

ESP8266 Power Monitor

You may also like...

Install ESP8266 SDK toolchain on Linux (Ubuntu 14.10 Desktop)

Connect Arduino to ESP8266 WiFi module

ESP32 from Espressif has Dual Core SoC, Features Faster WiFi, Bluetooth 4.0 LE, and More Peripherals and Pinouts than ESP8266

Products