Sharing for those searching for a similar solution, and thanks to @chris.huitema for the guidance
This solution reads my existing water meter and integrates the usage into Home Assistant, including the Energy dashboard.
Water Meter
Analog water meters (Read your water meter | South East Water - Type 1) in my area contain a port that can be used to measure usage through a reed switch. This port is located at the top left of the meter display and will have a black cap on it.
Raspberry Pi Pico W (but any ESPHome device with GPIO and GND pins will do)
3-core irrigation cable (0.5mm)
Plastic Reed Switch (normally open)
Installation
Attach reed switch to 2 of the irrigation wires and double back one side. Make sure you keep this as thin as possible so it will fit in the port. I personally was lazy and just tied the wires around each other and sealed with electrical tape, but I would recommend soldering. Remove the black cap from the meter and insert the switch as far as it will go. Run the irrigation cable to where you will keep your Pico, with access to power and Wi-Fi. On the other end of the irrigation cable, attach one wire to GPIO7 (any GPIO pin will do) and GND (any GND pin) of the Pico.
I have the cable running about 25m from the meter into my attic to an outdoor enclosure for power boards. You should be able to run the cable up to 50m while still reading the switch. The Pico is then powered from mains and is within reach of my Wi-Fi network.
Configuration
I’m using ESPHome on the Pico W as I find the integration with Home Assistant to be excellent and it is very easy to make configuration changes over the air.
Below is the sensor configuration to add:
Once configured, you can add sensor.water_usage_total to the Energy dashboard and configure your price per m3 (which is equivalent to kl that my provider uses).
Yes I did, with the assumption that the meter had the magnet on the 10L mark, however I later discovered this isn’t the case so the multiply filter isn’t required.
Have updated the original post as such.
I’m in the ACT, and have a meter which looks similar (hard to tell from a drawing) - it’s branded Elster, but seems to be the Honeywell unit. I found the T110 probe is meant to suit it.
I couldn’t find a model number on the unit itself, but it does look very similar to the Honeywell V100.
Looking at the T110 probe, I don’t think it would fit in mine as it doesn’t appear to have the same two-prong port, but it might work for you.
I’m trying to tackle a similar problem right now. I’m in Melbourne.
I decided I would first try to see if I could even read anything from the water meter, so I used an Aqara door sensor with an extended reed switch as I used for my gas meter.
I inserted the reed sensor into the 2 prong port, and sure enough, as water is used the contact is closed and opened.
I was going to put the smarts into Home assistant with an automation to increment a counter for every pulse as I do with Gas, but it seems with my water meter that it pulses more than once for every rotation of the last digit. Seems like 2 pulses on reed switch for every rotation. And my yaml skills arent great so i’m stuck here.
@barneyonline Did you have similar behaviour with your water meter and do you or anyone else have any additional info I can use to move forward?
I didn’t have that problem with my meter; every pulse equals 1 litre.
Since your not using ESPHome I can’t help you too much with a yaml as I’m not proficient myself, however I do cheat by using ChatGPT. This is what it suggested:
sensor:
- platform: template
sensors:
volume_sensor:
friendly_name: "Volume Sensor"
unit_of_measurement: "L"
value_template: >
{% set pulse_count = states('sensor.pulse') | int %}
{% set conversion_factor = 2 # Adjust this value based on your pulse-to-liter conversion %}
{{ (pulse_count // conversion_factor) | float }}
Give it a try and see if it works. Be sure to share what you get working back here.
I actually have ESPhome, works well.
I only used the contact sensor solution as I just done it for Gas and thats working perfectly, and since I had the components all laid out i was more curious if i could even get a reed sensor into the plug hole and detect something and it did.
I got a bunch of ESP8266s and ESP32s ready to go on hand also, and started compiling the code in espHome as I think thats the way to go.
The other reason for contact sensor was its low power using zigbee and its running off of 2 x AA rechargeables so i don’t need to source power for it. if I go ESP or pico i got to run it to the garage for power and run a lead over the concrete.
I appreciate your reply and i might even given that a shot to see what happens.
Ive only just started getting my water meter monitored yesterday and still trying to get my head around the calibration as am using ESPHome on a D1 Mini. I’m just using a jaycar glass reed switch sealed in heatsink and some silicon placed in the front port indicated in the diagram above and seems to be picking up pulses.
I have exactly the same meter here in Western Australia, and from the technical spec sheet Ive found each pulse represents 5L, maybe its an older type. I have also seen a spec sheet for 0.5L pulse registration for v100 series, but the counter registration of my meter didn’t align for those models.
5L per pulse, these have xxxxx.xxx digits on the front panel and very right most digit represents 1 L (10L per full revolution) as per the diagram at start of this topic
0.5L per pulse model - these have xxxx.xxxx digitson front panel and guessing that the right digit represents per 0.1L??
I’d just run a test to figure out what you’re getting: assume 1 pulse = 1L (as above), configure it and then fill a 1L jug from the tap. Check how many pulses you got and adjust from there.
If you find your water meter has recorded 2 pulses for 1L (i.e. 1 pulse = 0.5L), then update the config for the pulse_meter with the filter “multiply: 0.5” as below:
Thanks so much its, working. I had to adjust the last multiply to 0.5 both because I wanted it in Litres, and because 0.001 was still counting every pulse as 1 litre.
I have it setup roughly at the moment to run it for the night see how it goes, then i’ll neaten it all up tomorrow.
Then need to figure out how to track costs, but the hard part is done.
Does anybody have some guidence on the best type of reed switch to use?
I used a cheap glass one from Jaycar, soldered it up and popped it in some heat shrink and tested using a magnet, but it doesnt seem to be working when inserted into the meter at all.
Hi, this will be my first build, so I am stumbling around in the dark a bit. I hope this link helps. I have emailed them but not response yet and I cannot seem to order online.
It might pay to test the reed switch again with your meter and mark which side that you are putting the magnet on. If the glass reed is rotated the other way the water meter will be pulling it open and not closed. I see the shop purchased probe has a screw not only to hold it in but I’m guess it is to orientate it as well.
Just my thoughts
Cheers
Hi guys this is my first sensor that I have had a crack at putting in to HA. Thanks for the instructions and so far it is going great. The only part that is not working is that the Pulses / min is not showing anything. I am just shorting GPIO7 and Gnd not sure if that is the issue.
Thanks Bruce
I brought a few of these seem to be going fine just don’t bend one leg back too close to the switch or you might brake the glass. I wrapped mine around a small nail then soldiered the wires on and then in covered it in heat shrink. The internal diameter of the hole for the sensor / reed switch is 4.5mm