Show HN: Watering my Christmas tree with ESPHome

[invalidator]

I love ESPHome. The declarative language makes it fun and easy to do so many little tasks like this. Used with Home Assistant it makes it easy to create graphs of everything. Do I NEED to know how much water my tree consumes? No, but I like seeing it anyway!

When controlling physical systems I try to limit the damage they can do with simple interlocks. For instance, the relay I added to control my central heat is in series with a conventional thermostat which is set for a few degrees above pleasant.

Likewise, you can splice a float switch in line with the pump's power cable, positioned so it will cut off power if the water level nears the top of the tree stand. This will prevent the flood when the software decides to rebel against you.

[KennyBlanken]

You can also use a float sensor and relay to control the pump, and use ESPhome for monitoring only.

[johnz]

My thoughts exactly on using ESPHome.

My familiarity with float switches is limited to boats. Any you would recommend for this application?

[sircastor]

A number of years ago I set up a siphon tube running into our Christmas tree stand from a nearby bucket. The bucket had a false—gift wrapped box over it to hide it. Through some empirical testing I found the right water height for the stand and marked it with tape.

I wanted to make an electronic solution, but I think this fared better than whatever code I could write.

[lrasinen]

Also made one for this year. My particular challenge is that we need a heavy-duty tree stand to account for feline perturbations. This means the water capacity is pitiful (0.5 litres, perhaps). Also there's not a lot of room for float switches.

My design has an optical water level sensor and a cheap peristaltic pump, plus an ESP8266 for sanity ("if on for more than 5 mins, sound the alarm").

Sensor: https://a.aliexpress.com/_mtzF1L6 Pump: https://a.aliexpress.com/_mrGsfVO

[winrid]

It's a cool project. If you don't need a ton of capacity what I did in the past is used a bucket and just some rubber tubing. Once you pull the water through, it will auto-siphon to be the same level as the bucket. Lasted me a week while I was in san diego! :)

[buildsjets]

I bought one of these off Amazon a few years ago, called the HoHoHoH20.

https://www.amazon.com/HoHoHoH2o-Automatic-Christmas-Waterin...

[johnz]

That is what inspired me to try building something myself. How do you like it? Does it have any reliability issues?

[33a]

I built something like this but found that the electric arduino water sensor quickly became corroded after a week and a half and ended up replacing it with a float switch.

[gothroach]

I also built something along these lines about three years ago and use it every year. I started off with a stainless steel hall effect float switch and it's lasted so far, on its fourth year. I don't have a pump for my water, I use my RO system as a source and a solenoid as a valve. I do use a peristaltic pump to meter out Christmas tree preservative according to the readings from a flow meter on the water side though. It's worked wonderfully, even when changing tree stands.

[johnz]

Good to know. I thought about using both a float switch and an ultrasonic distance sensor.

[ge96]

They have capacitive moisture sensors too

[LeafItAlone]

I love this. Great work!

I’ve thought about doing the same thing for years. But in my experience, those cheap capacitive sensors fail quickly. Might be worse when the water gets all sappy or filled with needles.

What sort of fail safe do you have for when the sensor becomes inaccurate?

[johnz]

Thanks!

No fail-safe besides the limit of only running the pump for 10 seconds at a time. I will continue to keep an eye on the data being pumped to Home Assistant and look to add a condition if/when the sensor fails.

[larusso]

Love the project! One thing that would give me the Krepps is to have a 10 liter water bucket next to a mains power outlet. Just thinking about all kinds of ways Murphy could be right here.

Edit: I’m from Europe so for me that feels twice as dangerous. (Don’t know if double the voltage means double the danger though)

[ianlevesque]

I love it, but if you just want to water a tree the siphons work really really well.

[Havoc]

Heard those moisture sensors rust. Anybody have insight into whether that’s true ?

[moonleay]

See https://news.ycombinator.com/item?id=38595055 and https://arduino.stackexchange.com/questions/8938/do-water-se...

[29athrowaway]

A lazier version for the rest of us would be measuring how much time it takes to replenish the water once a day, and then turn on the pump for that amount of time each day.

You can do this with a IFTTT routine and a smart plug.

[LeafItAlone]

An issue with that is that the tree will (at least based on my experience) soak up a variable about of water while it is set up. And in general, it will decrease as time goes on (as the tree dies more and more). If you set up the routine based on the first few days, you will likely end up overflowing.

[csdvrx]

The tech is interesting, but what I like even more is that it may increase the chances of survival of the tree if the root ball hasn't been cut!

I hope there will be an effort to collect and replant Christmas trees, as the cultural practice of cutting down tree and letting them die slowly in front of us (just for our seasonal enjoyment!) strikes me as barbaric.

[sgerenser]

The trees are planted and farmed specifically to be Christmas trees. If nobody bought them, they wouldn’t be planted in the first place, so the act of cutting down then disposing of a Christmas tree has no net impact to the overall tree population (barring the small amount of Clark Griswolds out there who get their tree from a forest somewhere rather than a Christmas tree farm).

[ge96]

I wonder if they can cut the top off and let the rest grow

[snthd]

Why choose a pump over a siphon?

[dylan604]

because you can't program a siphon? a siphon isn't going to give you any data that you can then plot on a graph (if that's your kink). also, what kind of Show HN post would a siphon make? You'd just get a bunch of uninspired questions like this.

[kbar13]

the relay should just be <$5. no need for a whole 4 plug controllable power strip

[wferrell]

What a great post. Thank you!

[johnz]

Cheers!