(#28) That doggone total eclipse is gonna mess me up

It just dawned on me (pun soon to be intended) that the looming Total Eclipse is going to break one of my more useful web services for about an hour.  That web service is my "is it dark outside?" web service.

Sunrise, sunset...

In Home Automation, it's handy to know when the sun rises, when it sets and where we are at any given time between those two boundaries.  Here's my implementation in PHP:

<?php
 $aLatitude = htmlspecialchars($_GET["lat"]);
 $aLongitude = htmlspecialchars($_GET["lon"]);
 $aTimeZone = htmlspecialchars( (isset($_GET['tz'])) ? $_GET['tz'] : 'America/Denver' );

 //
 // uncomment one zenith setting: http://en.wikipedia.org/wiki/Twilight
 $zenith = 90+(50/60); // True sunrise/sunset
 //$zenith = 96;           // Civilian Twilight - Conventionally used to signify twilight
 //$zenith = 102;         // Nautical Twilight - the point at which the horizon stops being visible at sea.
 //$zenith = 108;         // Astronomical Twilight - the point when Sun stops being a source of any illumination.

 //
 // Good enough approximation at offset
 $tzOffset = $aLongitude * 24 / 360;

 //
 // But evidently, I need to deal with Daylight Saving Time myself
 if (date( 'I' )) {
    $tzOffset += 1;
 }


 $sunriseStr = date_sunrise( time( date_default_timezone_set( $aTimeZone )), SUNFUNCS_RET_STRING, floatval($aLatitude), floatval($aLongitude), $zenith, $tzOffset );
 $sunsetStr  = date_sunset(  time( date_default_timezone_set( $aTimeZone )), SUNFUNCS_RET_STRING, floatval($aLatitude), floatval($aLongitude), $zenith, $tzOffset );

 $isDark = FALSE;

 $date1 = DateTime::createFromFormat( 'H:i', date( 'H:i' ));
 $date2 = DateTime::createFromFormat('H:i', $sunriseStr );
 $date3 = DateTime::createFromFormat('H:i', $sunsetStr );

 if ($date1 < $date2 || $date1 > $date3)

 {

    $isDark = TRUE;

 }

 

 $result_json = array( 'sunrise' => $sunriseStr,

                       'sunset' => $sunsetStr, 

                       'currentDateTime' => $date1, 

                       'timezone' => $aTimeZone,

                       'inDST' => (date( 'I' ) ? '1' : '0'), 

                       'isDark' => ($isDark ? '1' : '0') );

 // headers to tell that result is JSON

 header('Content-type: application/json');

 // send the result now

 echo json_encode($result_json);

?>

It fits my needs. Pass in a Lat/Lon for the sunrise and sunset times at that location. Leave them off and it assumes you live near me.

It also returns the current date, time and timezone data for, you guessed it, me.

Invocation is pretty simple. Here's today's sunrise/sunset request for Seattle:

http://<yourwebserver:port>/<path>/sunrise.php?lat=47.6lon=-122.3

The result comes back as JSON:

{  
   "sunrise":"05:48",
   "sunset":"20:21",
   "currentDateTime":{  
      "date":"2017-08-10 09:29:00.000000",
      "timezone_type":3,
      "timezone":"America\/Denver"
   },
   "timezone":"America\/Pacfic",
   "inDST":"1",
   "isDark":"0"
}

Again - that currentDateTime object is for me.  Change it or remove it to fit your needs.  Once this webservice is in place, having other applications check to see whether it's dark outside or not is also pretty easy. A contrived python example:

import json

import urllib2

# My website needs authentication

password_mgr = urllib2.HTTPPasswordMgrWithDefaultRealm()

use it instead of None.

top_level_url = "http://<yourserver>/<path>/sunrise.php?lat=40&lon=-105"

password_mgr.add_password(None, top_level_url, <usr>, <passwd>)

handler = urllib2.HTTPDigestAuthHandler(password_mgr)

opener = urllib2.build_opener(handler)

urllib2.install_opener(opener)

data = urllib2.urlopen(top_level_url)

json_payload = json.load(data)

isdark = json_payload['isDark']

# do something

if isdark == "1":

   print "It is dark - turn on the outside lights"

else:

   print "It is light (not dark) - turn off the outside lights"

GOSUB 200 - Another Interruption - Daemons and Python

Plunking "instructions to myself" in a blog is useful, so here it comes again. This time it's about Python, Daemons and "systemd".

For code that I want to run all of the time and have it managed by the operating system there are a handful of approaches: write it as a daemon, write it as a executable and work up some cron scripts to keep it going, and now there's systemd.  Like it, revile it -- it looks like systemd is here to stay.

So, briefly, here's what I did to make my Python code managed by the systemd service.

It starts with a 'unit' file.  Bear in mind I have precious little information on what all of the options are, what the ones I've used actually do and the ramifications of the choices made.  

But here's what's working for me.

Step 1 - Create <useful-name>.service

$ more garagedoorcontroller.service

[Unit]

Description=Garage Door Controller Service

After=syslog.target

[Service]

Type=simple

User=myname

Group=mygroup

WorkingDirectory=/complete/path/GarageDoorController

ExecStart=/usr/bin/python /complete/path/GarageDoorController/GDController.py

StandardOutput=syslog

StandardError=syslog
Restart=always
RestartSec=60

[Install]

WantedBy=default.target

#

# After this the steps are:

# Create the unit file in /etc/systemd/system (the file name

# before .service will be the name you call to start/stop/restart the service)

# Set file permissions to 644

# Tell systemd that there is a new unit file: systemctl daemon-reload

# Start service: systemctl start <service>

# Check the service status: systemctl status <service>

Steps 2 and 3 - Copy it to the right spot

foo: $ sudo cp garagedoorcontroller.service /etc/systemd/system/.

foo: $ sudo chmod 644 /etc/systemd/system/garagedoorcontroller.service

Step 4 - Tell systemd that there's a new (or altered file)

foo: $ sudo systemctl daemon-reload

Step 5 and 6 - Start it, check the status

foo: $ sudo systemctl start garagedoorcontroller

foo: $ sudo systemctl status garagedoorcontroller

● garagedoorcontroller.service - Garage Door Controller Service

   Loaded: loaded (/etc/systemd/system/garagedoorcontroller.service; disabled)

   Active: active (running) since Wed 2017-08-09 09:35:17 MDT; 18min ago

 Main PID: 12961 (python)

   CGroup: /system.slice/garagedoorcontroller.service

           └─12961 /usr/bin/python /complete/path/GarageDoorController/GDController.py

Aug 09 09:35:17 rpi4 systemd[1]: Started Garage Door Controller Service.

Tail /var/log/syslog if you have problems. The error messages are descriptive.

The BSD daemon, also called Beastie (a near homophone of the letters B-S-D pronounced slurred together), as drawn by John Lasseter. His widely known and popular take on the BSD mascot first showed up on a book cover in 1988. 

[ From the Wikipedia entry on BSD Daemon. ]

(#27) - Home Automation, Lights and Normal People

Normal

Here's how normal people turn on the lights in the kitchen:

Not Normal

And here's how people enamored with Home Automation turn on the lights in the kitchen:

1. Fumble around in the dark, pull smartphone from pocket
2. Swipe around until Home Automation App found, launch app
3. Wait while Home Automation app starts
4. Swipe around and find the Lighting Tab on the Home Automation app
5. Swipe around and find the room labeled Kitchen
6. Press the On button

And the industry wonders why adoption just won't take...

Still, that's far too simple and straight-forward for me, so continuing our TCP Connected Lighting Gateway programming from the last post, lets cover two of the four commands we use.

DeviceSendCommand

DeviceSendCommandLevel

To control individual bulbs, you use one of these two commands. The first turns a bulb on and off. The second command will set the dimming level.

#------------------------------------------------------------

def set_light_value(self, did, value=1, update=True):

    rc = self.my_gateway.send_device_command(did, value)

    if update:

        self.load_rooms_and_devices()

    return rc

#-----------------------------------------------------------

def set_light_level(self, did, level=100, update=True):

    rc = self.my_gateway.send_device_command_level(did,level)

    if update:

        self.load_rooms_and_devices()

    return rc

And then the HTTPS calls to the gateway are:

The two strings, DeviceSendCommand and DeviceSendLevelCommand were shown back here.


The last two commands of the four affect an entire room and they're used in the same manner:

RoomSendCommand

RoomSendCommandLevel

#------------------------------------------------------------

def set_room_value(self, rid, value=1, update=True):

    rc = self.my_gateway.send_room_command(rid,value)

    if update:

        self.load_rooms_and_devices()

    return rc

#------------------------------------------------------------

def set_room_level(self, rid, level=50,update=True):

    rc = self.my_gateway.send_room_command_level(rid,level)

    if update:

        self.load_rooms_and_devices()

    return rc

No surprise here, the HTTPS calls to the gateway are:

The "update" variable is used to potentially postpone a call to reload the room and bulb status values. That call, the RoomGetCarousel call is a bit 'thick' and I wanted to avoid calling it if I'm doing multiple bulb updates,

(#26) - Let there be light! 

Insufficient coffee to fuel any witticisms or snarky remarks means I'll cut to the chase. The lighting controller in my house is from a company called TCP Connected. I've discussed the challenges I've had with their product back here.  

(#25) My IoT Garage Door Closer

Problem with a 'p'

There's a big problem with leaving your garage door open at night.

And the problem is that the thieves never take the stuff you want them to take. 

Do they grab the box of outdated college text books from 1985? 

No. 

Do they grab the mostly-empty can of Oldham Tudor Earth Tone brown paint you bought in 1995 when that color was in vogue? 

No.