Add note about sensors

content/.obsidian/workspace

@@ -4,12 +4,12 @@
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@@ -69,7 +69,7 @@
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@@ -86,27 +86,28 @@
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     "Protospace.md",
-    "t0txt.md",
-    "Notica.md",
+    "Plant Waterer.md",
+    "QotNews.md",
+    "Solar Car.md",
     "Spaceport.md",
+    "t0txt.md",
     "Backup Strategy.md",
-    "p.md",
-    "media/Screenshot from 2022-05-18 16-24-38.png",
-    "media/Pasted image 20220518162452.png",
-    "media/Pasted image 20220518162414.png"
+    "Notica.md",
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content/Backup Strategy.md

@@ -165,7 +165,7 @@ The `tbotbak` user has write access to the `/mnt/backup/remote/tbotbak` director
 
 I run a lot of services for [Protospace](https://protospace.ca/), my city's makerspace.
 
-The member portal I wrote called [Spaceport](https://my.protospace.ca/) creates an archive I download daily:
+The member portal I wrote called [[Spaceport]] creates an archive I download daily:
 
 ```
 40 10 * * * wget --content-disposition \

content/Sensors.md

@@ -0,0 +1,17 @@
+Title: Sensors
+Date: 2022-05-24
+Category: Notes
+Summary: A dashboard for various sensors around my house.
+Short: d
+
+I wrote a custom [dashboard](https://sensors.dns.t0.vc/) to visualize data from various sensors around my house. I'm a huge fan of sensors because they're at the intersection of what I love: electronics, home automation, and data hoarding.
+
+You can find the [source code](https://git.tannercollin.com/tanner/sensors) on my Gitea.
+
+![[sensors1.png]]
+
+Most of the data is captured by two cheap RTL-SDRs (software-defined radios) that are set to listen to 433 MHz and 915 MHz radio frequencies. I use the open-source project [rtl_433](https://github.com/merbanan/rtl_433) to automatically decode the signals and forward them to an MQTT broker, which is a messaging server that services can publish and subscribe to. Other sensors run an MQTT client directly or expose their data through other means like a web interface that I poll.
+
+The data gets collected by a central Python script that process and stores it in an InfluxDB database for "efficient" storage. The script also runs a web server that queries the database and exposes the data over an API to the dashboard at various dates and ranges. The dashboard is written in JavaScript / React using a simple chart library.
+
+My biggest regret was using InfluxDB. It's a stupid database and I wouldn't recommend it to anyone. The documentation is confusing and I ran into timezone issues with `group by time()`. It also assumes the column data type is an integer if your sensor happens to send it a whole number at first and it won't let you change that. Just stick to Postgres / SQLite.