I have owned the Eve Aqua HomeKit water controller for a number of years. The latest version now with added thread support had me considering how I could put the device to better use. In Northern Ireland it’s rare to see a time when lawns need to be watered regularly when we do see such a mini heatwave, it is often accompanied with a hosepipe ban.
My application is a little different and goes indoors. I have an Eve Degree in the greenhouse that I use to track temperate over the last few years and it is not uncommon to see temperatures over 50 degrees Celsius. My aim was to create a mini-irrigation network for the various plants, fruit and vegetables growing in the greenhouse.
The cost of the project is around £100 but should offer a number of years watering as long as I remember to put it away during the winter months. The Eve Aqua costs around £80 and the irrigation system approximately £23. Also note that for around the clock automation you need to have a HomeKit hub running (for example an AppleTV, HomePod, HomePod mini).
My aging Eve Degree in the Greenhouse
Stage one involved creating a Y junction at the tap (this will be controlled by HomeKit / Eve Aqua). The Y will direct water to the greenhouse but at the same time allow for a watering can to be filled or a sprinkler to be set up for the outdoor plants.
The Eve Aqua
The Y adapter also came with a stop adjustment so you can have water flowing along each route individually or simultaneously. This is useful if you want to fill a watering can and not have the full system running. The Eve Aqua also comes with a master ON/OFF switch on the front so users can still activate the water without Siri or the app. This button can be deactivated in the Eve App.
A standard hose pipe runs to the door of the greenhouse where it integrates with the micro hose system via a butterfly clip. The irrigation kit came with a split adaptor so I have two strands (each side of the greenhouse) that each has it’s own stop switch. (see photo below (orange adaptor)).
The biggest challenge was routing the water network around the already establish plants in the greenhouse. The £24 kit came with a range of different connectors and water distributors (for want of a better term). I located each distributor around the various plants then routed the flexible pipe accordingly. The network needed a little bit of thought and involved a range of T junctions and pass throughs. I decided to cut the hose with reasonable generosity so the pieces could be moved around as the plant population changes.
The images above show the various connectors and the mini stopcock. I routed both sides of the greenhouse individually this means one section can be turned off as plants leave the greenhouse and thus reduce water waste. It’s worth spending a bit of time ensuring the hose is well connected the various T junctions and outlets. This can be fiddly work to ensure a proper attachment but it’s worth doing it right. I managed to design my water network without the need to use any of the little terminators, this was down to the fact I had two or three occasion when these shot across the greenhouse at speed.
On completion of the network I still had a large number of connectors and a large amount of hose. This means I can grow, change and replace parts of the system should I need to in the future.
My algorithm is actually fairly basic and crude. It is simply a routine to turn on the Eve Aqua for 2 minutes at sunset and again at sunrise. I would love to see the homekit automation engine develop to a little bit more of a programming language.
For example, there is an input device in the form of an Eve Degree and although I can trigger an action based on a temperature I won’t always want that to be instant. For example, if the greenhouse reaches 40 degrees, I may want to water the plants for a little longer, but I will want to do it later in the day when the plants are not under direct sun.
It would be great to be able to control variables:
If the temperature in the greenhouse >30oC
then water = true.
If time is 3am and water = true
then turn on Eve Aqua for 7 minutes.
Siri Shortcuts help here (ish). The Eve app includes a “Check Watering” shortcut that will check the chance of rain in the weather forecast for your chosen location. It does this by accessing the Weather app on the iPhone. You then just set the value above which you want watering to be paused.
This would be perfect if I was watering outdoor plants, but it obviously doesn’t help with a greenhouse situation. The shortcuts app might be the solution although these still need to be actioned by the end user. If anyone has any insight or tips please feel free to share in the comments.
The simple Routine
The daily routine still offers a level of intelligent automation. I may adjust the automation for 30 minutes before sunset and for 4 minutes. I will keep an eye on the environment and app and adjust the program as the summer progresses.
The Eve Aqua also offers metrics on water consumption (if you know the flowrate for your tap), this includes the usual Eve graphical output. The problem in my setup is that the overall flow is limited by my finer hosing and different outputs at the end of each node. In reality I will ensure water efficiency by monitoring the plants and making fine adjustments to the schedule.
Some may consider this solution to be like using a sledgehammer to crack a nut. On one hand it made for a nice little Homekit project that was relatively low cost. The upsides are that I can ensure plants are watered should I forget or be on holiday. The biggest upside is efficiency, the micro tubing allows for water to be directed to where it is needed most, no waste watering the entire area with a watering can. One of the biggest challenges is fighting the temptation to say “hey Siri turn on the garden tap” when someone is in the Greenhouse.