This contains code for a small project to monitor and document the water usage of my garden sprinkler system.

This can help understand where the cost goes, if there are unexpected leaks etc.

There are a few projects like that on github already, but they seemed either overkill or didn't really meet what I needed.

Hardware:

• I sat up a in-line hall flow meter such as
  • https://www.amazon.com/dp/B07MY6LFPH
  • https://www.amazon.com/DIGITEN-Sensor-Switch-Flowmeter-Counter/dp/B00VKAT9VA
  • https://www.amazon.com/FASTROHY-Sensor-Copper-Effect-Flowmeter/dp/B07JZXBKJR
  • https://www.banggood.com/DN20-G34-Copper-Water-Flow-Sensor-Pulse-Output-1_75Mpa-245Lmin-Flowmeter-p-1266296.html
  • https://www.aliexpress.com/item/32247118868.html

These flow meters all seem the same model, rebranded, but I have not compared them. While they are inexpensive, it was not trivial to install them without leaking - I'm also not certain about their long-term reliability yet.

My flowmeter says that it's frequency is 5.5 Hz * Q, where Q is the flow in litres/minute. That means one liter trnaslates into 330 pulses. I let the sprinkler run for a few minutes, checked our official utility water meter before and after, and compared with the number of pulses on the flow meter. As far as I can tell, the flow meter is fairly accurate (less than 10% deviation).

• I also used an elderly esp8266 wemos D1 with micropython. I just connected GND and 5V to the flow meter and the data pin to D4 (GPIO2?).

• I run the main.py on the Wemos D1. Other than configuring the network, the only other thing to do here is to specify where to send the measured data to.

• Since I don't trust the D1 to stay up for extended periods of time, I periodically send the collected data to a separate server that keeps a more permanent log. The water_server.go file implements the server, you can start it with go run water_server.go. I do this in a screen session on a raspberry pi for now.

• Finally, I included a small python script to plot the data.

PUBLIC DOMAIN ----------------------------------------------------------------------

I, the copyright holder of this work, hereby release it into
the public domain. This applies worldwide.

In case this is not legally possible, I grant any entity the
right to use this work for any purpose, without any
conditions, unless such conditions are required by law.