Adventures in Home Automation – Part IV The Garden

In Part IV of our Adventures in Home Automation, we venture outside.

We setup a greenhouse a couple of months ago, and all of our outside water distribution is handled within the greenhouse, including where we feed into the sprinkler system.

Greenhouses are unique environments. They get hot, they get cold, they get humid, and often, they’re not humid enough. One thing that becomes evident in an Australian summer though is that they get warm quickly. Even on a mild, mid 20C day, it’s often around 40C in there.. even with some shade cloth over the roof.

We have a vent lifter – basically a temperature reactive mechanism that opens and closes the roof vent based on temperature. Non-technical, but effective. Still, there’s a lot more to it.

We put in a smart thermometer to measure temps and humidity. We also put in a 12v thermostat that fires the fans up over a set temperature. Our 12v comes from an adjacent garden shed’s solar set up. One fan used for pushing air into the greenhouse. The other is for circulation. Heat can then escape through the roof vent.

We installed a misting system – a pretty basic cheap Holman system that cost all of $28. The purpose of this one is to cool the greenhouse and bring the humidity up during the day. We’re in Victoria, so hot days here tend to be quite dry. We connected this to a Holman WX1 water controller.

The choice for this gizmo was mostly just because we were in a hurry, and it was available. At some point when we need more, we’ll be scouring our overseas sources for generic versions of the same thing.

The WX1 is sold in 2 versions – just the tap controller itself, or the controller and the required WiFi Hub that supports up to 4 tap controllers. Holman have an app for it, but you can import it as an irrigation controller into Tuya/Smart Life.

Something to be aware of:

– It appears that the controllers use a VHF radio signal back to the WiFi hub. From there, the device talks on 2.4GHz, so the hub needs to be in reasonable proximity to the WX1 devices. In our case, we connected one to the 240v in our back garden shed. Said garden shed also has a wireless access point outside of it, so that’s not really a problem.

We were able to setup a smart scene to check the thermometer and start the misting system under two scenarios:
– When the greenhouse temperature is over a threshold and the humidity is under a specific threshold. When the mister has run, the humidity rises quickly, but the temperature will likely stay over the temperature threshold. The idea here is to stop it running all day – but rather to have some logic to wait until it dries out then fire it up again to bring the moisture back into the air. 

– When the humidity drops below a specific threshold regardless of temperature. This threshold is lower than the above but is really just there to ensure that there is some humidity in the space. This really shouldn’t run often.

The WX1 needs two specific functions configured to make it work:

– A manual water time – how long it is to run for.

– A setting to tell it to water manually.

The device in Smart Life looks to be able to monitor water use, but we’ve never seen this change. Possibly it doesn’t quite work in Smart Life, and we’re not interested in using the Holman recommended app to compare it.

Overall this is a pretty cool little smart integration.

The only draw back we’ve seen is that Home Assistant doesn’t really know what to do with it. The WiFi hub acts as a smart switch as well for a power socket on it. Home Assistant seems to just want to drive that and nothing else.

Doing some research, there are some folks who’ve managed to get some additional functionality by using Tuya Local and fiddling around. That’ll be an interesting “one day” exercise.

The Sprinkler System:

We have a single sprinkler system running around all of our backyard garden beds, which also has a drip system over our veggie garden. At the moment we have the Holman BX1 – a bluetooth tap controller similar to the WX1 – just not as smart. At the moment it’s limited to a program of 3 cycles per day (its programming limit).

It’s a surprisingly reasonable gizmo – the Bluetooth connection works over greater distance than expected but is completely hamstrung by its limited number of programming cycles. Unlike the WX1, you’re stuck using the Holman app.

We’re not going to keep this one doing this job much longer. It’ll get replaced with another WX1. It’s worth mentioning that even the WX1 in Smart Life/Tuya has the same limitations on the number of watering cycles a day that can be pre-programmed. But.. there’s nothing stopping us adding some additional smarts into the programming.

The big one for us is simply making our watering system understand the weather. Our location isn’t known for being warm or dry. We’ve had a few rather miserable days recently despite summer and much of the year will likely be miserable too.

In Smart Life, we can setup some functionality to run the watering system multiple times a day – dependent on the weather. If it’s going to rain, it won’t run. If it is unlikely to rain, it will run. Easy.. and smart.

We don’t be having to micro-manage the gardening daily. It’s pointless and we’re too busy for that. Putting in this level of automation takes away that tediousness.

At some point our watering system will increase as we sort out the rest of our yard. That’ll bring a scale up in this automation.

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