Category: Home Automation

Farm Automation

Scott set up one of the ESP32’s that we use as environmental sensors to monitor the incubator. There’s an audible alarm if it gets too warm or cold, but that’s only useful if you’re pretty close to the unit. We had gotten a cheap rectangular incubator from Amazon — it’s got some quirks. The display says C, but if we’ve got eggs in a box that’s 100C? They’d be cooked. The number is F, but the letter “C” follows it … there’s supposed to be a calibration menu option, but there isn’t. Worse, though — the temperature sensor is off by a few degrees. If calibration was an option, that wouldn’t be a big deal … but the only way we’re able to get the device over 97F is by taping the temperature probe up to the top of the unit.

So we’ve got an DHT11 sensor inside of the incubator and the ESP32 sends temperature and humidity readings over MQTT to OpenHAB. There are text and audio alerts if the temperature or humidity aren’t in the “good” window. This means you can be out in the yard or away from home and still know if there’s a problem (since data is stored in a database table, we can even chart out the temperature or humidity across the entire incubation period).

We also bought a larger incubator for the chicken eggs — and there’s a new ESP32 and sensor in the larger incubator.

Building Gerbera on Fedora

There is a great deal of documentation available for building Gerbera from source on a variety of Linux flavors. Unfortunately, Fedora isn’t one of those (and the package names don’t exactly match up to let you replace “apt-get” with “yum” and be done). So I am quickly documenting the process we followed to build Gerbera from source.

The Fedora build of Gerbera has the binaries in /usr/bin and the manual build places the gerbera binary in /usr/local/bin — the build updates the unit file to reflect this change, but this means you want to back up any customizations you’ve made to the unit file before running “make install”.

You need the build system — cmake, g++, etc and the devel packages from the following table as required by your build options

Library Fedora Package Required? Note Compile-time option Default
libpupnp libupnp-devel XOR libnpupnp pupnp
libnpupnp Build from source (if needed) XOR libupnp I was only able to locate this as a source, not available from Fedora repos WITH_NPUPNP Disabled
libuuid libuuid-devel Required Not required on *BSD
pugixml pugixml-devel Required XML file and data support
libiconv glibc-headers Required Charset conversion
sqlite3 sqlite-devel Required Database storage
zlib zlib-devel Required Data compression
fmtlib fmt-devel Required Fast string formatting
spdlog spdlog-devel Required Runtime logging
duktape duktape-devel Optional Scripting Support WITH_JS Enabled
mysql mariadb-devel Optional Alternate database storage WITH_MYSQL Disabled
curl libcurl-devel Optional Enables web services WITH_CURL Enabled
taglib taglib-devel Optional Audio tag support WITH_TAGLIB Enabled
libmagic file-devel Optional File type detection WITH_MAGIC Enabled
libmatroska libmatroska-devel Optional MKV metadata required for MKV WITH_MATROSKA Enabled
libebml libebml-devel Optional MKV metadata required for MKV WITH_MATROSKA Enabled
ffmpeg/libav ffmpeg-devel Optional File metadata WITH_AVCODEC Disabled
libexif libexif-devel Optional JPEG Exif metadata WITH_EXIF Enabled
libexiv2 exiv2-devel Optional Exif, IPTC, XMP metadata WITH_EXIV2 Disabled
lastfmlib liblastfm-devel Optional Enables scrobbling WITH_LASTFM Disabled
ffmpegthumbnailer ffmpegthumbnailer-devel Optional Generate video thumbnails WITH_FFMPEGTHUMBNAILER Disabled
inotify glibc-headers Optional Efficient file monitoring WITH_INOTIFY

Then follow the generalized instructions — cd into the folder where you want to run the build and run (customizing the cmake line as you wish):

git clone
mkdir build
cd build
make -j4
sudo make install

As with the Gerbera binary, the Fedora build places the web content in /usr/share/gerbera and the manual build places the web content into /usr/local/share/gerbera — yes, you can change the paths in the build, and I’m sure you can clue Gerbera into the new web file location. I opted for the quick/easy/lazy solution of running

mv /usr/share/gerbera /usr/share/gerbera/old
ln -s /usr/local/share/gerbera /usr/share/

To symlink the location my config thinks the web components should be located to the new files.

On the first start of Gerbera, SQL scripts may be run to update the database — don’t stop or kill the service during this process there’s no checkpoint restart of the upgrade process. We backed up /etc/gerbera/gerbera.db prior to starting our Gerbera installation. We’ve also wiped the database files to start from scratch and test changes that impacted how items are ingested into the database.


Gerbera – Searching for Playlists

Summary: Playlist items are not returned from searches initiated on my uPNP client. The playlist is visible when browsing the Gerbera web UI under Playlists->All Playlists->Playlist Name and Playlists->Directories->Playlists->Playlist Name

Action: In a uPNP client, search using the criteria upnp:class = "object.container.playlistContainer" and dc:title = "Playlist Name",

Expected Results: Playlist matching search criteria is returned
Actual Results: No results are returned

From the Gerbera debug log, the search being executed is:

SELECT DISTINCT "c"."id", "c"."ref_id",
"c"."parent_id", "c"."object_type", "c"."upnp_class", "c"."dc_title",
"c"."mime_type" , "c"."flags", "c"."part_number", "c"."track_number",
"c"."location", "c"."last_modified", "c"."last_updated"
FROM "mt_cds_object" "c"
INNER JOIN "mt_metadata" "m" ON "c"."id" = "m"."item_id"
INNER JOIN "grb_cds_resource" "re" ON "c"."id" = "re"."item_id"
WHERE (LOWER("c"."upnp_class")=LOWER('object.container.playlistContainer'))
AND (LOWER("c"."dc_title")=LOWER('Playlist Name'))
ORDER BY "c"."dc_title" ASC;

The playlists do not have a row in the grb_cds_resource table, so the “INNER JOIN” means the query returns no records.

I am able to work around this issue by manually inserting playlist items into the grb_cds_resource table

INSERT INTO grb_cds_resource (item_id, res_id, handlerType) VALUES (1235555,0,0);

If I have some time, I want to test changing join2 to be a left outer join and see if that breaks anything.

Reverse Proxying WebSockets through mod_proxy — HTTP Failback

I’ve been successfully reverse proxying MQTT over WebSockets via Apache HTTPD for quite some time now. The last few weeks, my phone isn’t able to connect. There’s no good rational presented (and manually clicking the “send data” button on my client successfully connects). It was time to upgrade the server anyway. Once I got the latest Linux distro on the server, I couldn’t connect at all to my MQTT server. The error log showed AH00898: Error reading from remote server returned by /mqtt

Evidently, httpd 2.4.47 added functionality to upgrade and tunnel in accordance with RFC 7230. And that doesn’t work at all in my scenario. Haven’t dug in to the why of it yet, but adding ProxyWebsocketFallbackToProxyHttp Off to the reverse proxy config allowed me to successfully communicate with the MQTT server through the reverse proxy.

(Not) Finding the Rygel Log File

We’ve spent a lot of time trying to get a log file from the rygel server … setting the log level in the config file didn’t seem to do anything useful. And I cannot even find a log file. The only output we’re able to find is formed by running the binary from the command line. Where is that log file?!? Hey — there isn’t one. All of this log level setting has to do with what’s written to STDOUT and STDERR. You can either modify the unit file to tee the output off to a file or run it from the command line

To get debugging output, use

G_MESSAGES_DEBUG=all rygel -g 5

To tee the output off to a file,
rygel -g *:5 2>&1 | tee -a /path/to/rygel.log


Home Automation and Gardening

Something like 20 years ago, I tried to grow a plumeria flower in my apartment. I had a broad-spectrum light, plenty of heat, and plenty of humidity. But getting the light turned on and off at the right times wasn’t easy (especially if I was at work all day!).

This seems like a really good use for home automation — our home automation system tracks the sunrise and sunset times for our zip code. It’s possible to essentially cron “stuff” off of these times — e.g. get the birds ten minutes before sunset. I could easily track sunrise and sunset in Honolulu then have my light turn on at sunrise (or first light) and off at sunset (or last light). Voila — “sunlight” that runs for the proper duration every day.

Blocking Device Internet Access

We block Internet access for a lot of our smart devices. All of our control is done through the local server; and, short of updating firmware, the devices have no need to be chatting with the Internet. Unfortunately, our DSL modem/router does not have any sort of parental control, blocking, or filtering features. Fortunately, ISC DHCPD allows you to define per-host options. Setting the router to the device’s IP ( may work as well) allows us to have devices that can communicate with anything on their subnet without allowing access out to other subnets or the Internet.

OwnTracks WebSockets MQTT SSL Error

A few weeks ago, we stopped getting location updates from OwnTracks on our phones. Checking the status, I see an error indicating that the connection failed because my certificate does not have a SAN. Which … true, it does not. I knew some consortium agreed that all certs should have SAN values (and RFCs had been updated to reflect this new direction). Evidently version 2.2.2 of OwnTracks has added SAN verification. I reissued the certificate from my CA and added a SAN. I had to put the cert on both my MQTT websockets reverse proxy and the mosquitto server; but, once both were using the new cert, OwnTracks connected and cleared through the queued updates.

ESP8826 (12e) Multisensor

We’d set up a prototype multi-sensor with an environment sensing kit that Scott picked up at MicroCenter a few years ago. There’s a little LCD display … but we wanted to report readings back to our OpenHAB server. Which required a network connection. Checking out prices for network cards to add to the Uno … well, it wasn’t a cheap add-on. But we found these ESP8266 modules that support 802.11b/g/n and provide the memory/processing for small programs. At about 3$ delivered, that was exactly what we needed.

I ordered a bunch of components to make multi-sensors – pressure sensors, luminescence sensors, temperature/humidity sensors. The sensors connect into a CP2102 ESP8266. The device is powered by a couple of 18650’s in a little box — another buck. There’s some miscellaneous wiring and a little breadboard, too. The total cost for the multi-sensor is about 8.50$. We could add a vibration sensor for another 0.50$, a PIR sensor for 2$, and a UV sensor for 2.50$. That’s 13.50$ for 7 different sensors — and we don’t need seven sensors everywhere.

I kind of want to make a weather station too — add a water level sensor, a precipitation detector, and a wind speed sensor. Those are surprisingly expensive! I want to check out the process to build your own anemometer. But I’d probably buy a nice Davis Anemometer 🙂

Connecting to a WiFi network with the ESP8266 is really easy:

  • Add a library to the Arduino IDE — In the Arduino IDE preferences, add ‘’ into the ‘Additional Board Managers’ URL, then install the ESP8266 library and select the board. I ordered the CP2102 ESP8266 module, and we’re using “” as the board.
  • Configure the WiFi network connection details in your code
  • Compile
  • Upload
  • You’ve on the network!

We’ve used an MQTT library and send sensor readings to our MQTT server.