Application virtualization, IoT and Cloud Computing, Blog of Sacha Thomet

Monthly Archives: November 2015

Another LaMetric IoT script – power control

Because I have currently holiday here is another post which is not related to virtualization …

I combined my new “gadgets” the LaMetric time and my new wifi Smart-Plug from MyStrom. The goal was to report the current power consumption of power plug and the possibility to control the plug with the smart ticker.

MyStrom has a very straight forward API (https://mystrom.ch/en/mystrom-api), and the possibility to create apps for LaMetric is pretty easy what I’ve already mentioned in an past┬áblog post.

All what is needed to implement this solution is:

  • a web server which can parse PHP
  • two small scripts
  • and a private app for LaMetric

This is the script to see the current power consumption:

{
    "frames": [
        {
            "index": 0,
            "text": " <!--?php //$host = "http://192.168.1.59/report"; //Call with parameter, e.g.: http://192.168.1.20/LaMetric/myStrom.php?host=192.168.1.59 $host = "http://" . $_GET&#91;"host"&#93; . "/report"; $filestring = file_get_contents($host); $startpos = 0; while($pos = strpos($filestring, "\"power\"", $startpos)) { $string = substr($filestring, $pos, strpos($filestring, ",", $pos + 1) - $pos); //echo $string. " "; $newstring = str_replace("\"power\": ","","$string"); echo round($newstring, 2); $startpos = $pos + 1; } ?--> Watt",
            "icon": "i1692"
        }
    ]
}

I just read the content from the API, which is already in JSON format, but I reformat it that it is in that way which I need to bring it to the LaMetric.
This is the script to control the power outlet:

<!--?php $host = "http://" . $_GET&#91;"host"&#93; . "/report"; $filestring = file_get_contents($host); $startpos = 0; while($pos = strpos($filestring, "relay", $startpos)) { $string = substr($filestring, $pos, strpos($filestring, "}", $pos + 1) - $pos); $newstring = str_replace("relay\": ","","$string"); //echo $newstring; $startpos = $pos + 1; } $newstring = str_replace(chr(13), "", $newstring); if ($newstring == "false ") { echo "Ist ausgeschaltet, wird nun eingeschaltet"; $URL = "http://" . $_GET&#91;"host"&#93; . "/relay?state=1"; $data = file_get_contents($URL); } else { echo "Ist eingeschaltet, wird nun ausgeschaltet"; $URL = "http://" . $_GET&#91;"host"&#93; . "/relay?state=0"; $data = file_get_contents($URL); } ?-->

And the LaMetric private app:

This simple poll app call the script on the webserver (192.168.1.20) with the parameter of the MyStrom plug (192.168.1.59).

On button action the controller script is launched with change the status (off to on or visa verse)

myStromApp-mini

(192.168.1.59 is the ip of my Power outlet. 192.168.1.20 is the address of my web server, this can be a raspberry pi or a Synology.)