Plant for electronics project recommendation please.

Hi,

New forum user here and not a plant person ... so far. ;-)

Basically I'm looking for recommendations re a suitable plant for an electronics project I'm running and would like one as near to my ideal as possible.

My wish list (in a loose order of importance):

It needs to be an indoor plant.
It ideally needs to be fairly tolerant to a range of water(ing) levels but actually be fairly demanding for water.
I'd prefer something that doesn't grow too big or grow big quickly.
It needs to be fairly durable (partly because of the first point but in general).
Ideally it would grow up from the pot but stay within it (not a climber or something that cascades down)?

Anything come to mind please?

The *reason* for wanting such a plant is because I need a test subject for a Home Automation project where I monitor the moisture level of a plant using a capacitive probe and the readings taken, displayed and logged by my Home Assistant system and potentially automatically watered using a mini home made system.

This isn't going anywhere particularly (I have no interest in any commercial application), it's just an idea that was initiated by a friend who has helped me with some coding, who has inherited some plants and is frightened he might kill them (from lack of watering potentially) and who also might be interested in a roll-it-yourself auto irrigation solution. ;-)

I did pick up a Begonia from Homebase a couple of weeks ago and I'm using that so far but one day it all looked lovely with a nice head of white and pink flowers and the next morning it was all limp and dangling with the stems all mushy at just above soil level?

A couple of stem still seem ok, so I'll see how it goes.

What I would need from the plant therefore is to be able to tolerate a fairly wide range of watering levels, from fairly dry to running out of the (bottom of the) pot so that I can have a reasonable range of levels to work with.

I currently have two probes in there, one just logging a chart to the Internet and another to Home Assistant and from there to the Internet.

Sorry for the long post and I look forward to any plant suggestions. ;-)

Cheers, Tim

 

Not many indoor plants will tolerate that difference in watering (not with my limited knowledge anyway)
The only one's that I've seen that tough are spider plants, but you say you don't want any cascading so that's out.
Hopefully someone with more houseplant experience might have a suggestion. Good luck.

 

Thanks for your thoughts JR. ;-)

It's not that I don't want a cascading plant as such, just that because of the nature of this project, it would mean it being higher up and so not easy re the plumbing etc. However, if it turns out that the spider plant really is an ideal solution, I might be able to put it somewhere different where it can do it's thing.

If I didn't do that and with the thought that 'what can go wrong, will go wrong', if / when I move to an auto irrigation stage, I would have to arrange for a return path for the water, should the pump run continuously for some reason.

A plant that did come up in my Googling that could be a candidate was the coleus but I thought I'd ask here?

Cheers, Tim

 

Hi and Welcome to the forum,

As for a plant, you do not actually need one, a light compost in a 5" pot will dry out on its own and activate a water pump etc as you can see below, thoug a plant would hasten the action.

Did have a long PM conversation with another member the other year about doing a similar plant pot moisture project.

I did some basic tests as you can see, recording the reading to a SD card etc but in the end she did not have the time to develop the project.

While auto watering is possible, assume in your case its for use in the house/flat, so as you say you need to build real safeguards into the software and hardware to avoid damaging leaks etc .

What micro are you using for your project, the Rasp PI or Arduino or other ?

Our greenhouse controller has an Arduino, though we are looking at updating the old lcd screen for a new TFT touch.

 

Sounds like a job for rice.

 

Hi Ricky and thanks for the welcome and feedback.

Yes, you are right, a pot of compound of some sort but I thought I'd try it with a real plant as long as I was having a pot of something on the mantelpiece. ;-)

It's also good to find someone with similar interests to me.

I have used many of the Arduino microcontrollers for all sorts of thing and a Arduino Mega runs the 3D printer I built, but in this case it's a ESP32 and ESP8266 reporting either directly to ThingSpeak or using the ESPHome integration on my Home Assistant (freeware) Home Automation solution.

That was running on a Raspberry Pi3B+ but I recently moved it onto an Odroid N2+ box, because of not wanting to risk the SD card wearing out because of the constant writes (logfiles etc). It's also more powerful than the RPi but consumes less energy (~2W or so!).

I initially got into Home Automation via a Lidl promotion (smart lights and switches), then some more Ikea smart lights and remote controls, then Sonoff smart switches for things like the strip lights in the kitchen (most of that using the Zigbee wireless system) and then the roll-you-own WiFi stuff using the ESP range.

So far I have light level sensors, an 8 way battery charger switch (switching an intelligent charger between up to 8 12V LA batteries), temperature probes monitoring the freezer (and soon also another freezer and fridge), managing a dehumidifier, the 3D printer, my Synology NAS and monitoring remote air pollution sensors etc etc. It really is a very flexible hub for all things.

Why I think it might work well for a automatic plant watering solution are many fold.

Firstly you can add and log sensors (I used the same capacitive sensor as you) and even tweak / upload the code to the remote sensors over the air (WiFi).

Secondly you can make things happen remotely, either manually or automatically via an 'Automation' (generally created via the GUI from a series of menu options).

Like, if I wanted to monitor the moisture level of a plant and then turn on a small pump for 5 seconds but only when the sun was in and above a certain temperature, you can (assuming you have all the sensors etc).

So an automation starts with a 'Trigger' of some sort, for this it might be 'When moisture level is below 50%', then you (can) have a condition, 'If the light level is below 100 lux' or 'If it's after 6pm' and then you have an action, like 'Turn on the pump (for 5 seconds)'.

So whilst the capacitive sensor and the relay to drive the pump might be connected to the same microcontroller (that cost less than £5 each btw!), the logic that links them is in Home Assistant and so makes the whole thing much more flexible. Like, you can check the logs / history and display the activity for the moisture level, the light level, the pump on times over say the last week (or longer potentially) and see how they all pan out, you can even have an ESPCam take pictures of the plant at regular intervals. ;-)

And you can view / control all this from your PC, tablet or phone. ;-)

I have PIR sensors in most of the rooms that are passed though (hall / landing) or you don't stay in all day (kitchen) that turn the lights on and keep them on whilst they detect any movement. So when I walk into the study it turns on the smart light, the over workbench light and under workbench LED strip and 5 mins after I walk out it turns them all off and mutes Google Home if it's on. ;-)

It still amuses me to walk round the house and have the lights do their thing, handy when you have your hands full. ;-)

Cheers, Tim

 

Do you mean rice the plant or someone here called 'Rice' Pete. ;-)

Once I've refined this moisture monitoring solution on this pot-plant, I want to extend it to a couple of outdoor plants that daughter has provided for us in pots and planters to avoid getting told off when she visits and she doesn't think I've been attending to their watering sufficiently.

The sensors would still be within easy range of our WiFi and could probably be solar powered (given it would generally be the summer when watering would be an issue).

I think it's possible to have the little microcontrollers go to sleep, only waking up say every hour to 'phone home' with their moisture readings (further saving battery power etc).

Cheers, Tim

 

This is a very interesting project

From plant perspective, the challenge with any new plant you bring home from supermarket or nursery is that they will usually need re-potting and then a period of settling in until there is strong new growth of new roots. The risk of losing the plant is high as they have been professionally grown and suffer a shock when brought into a room. Some recover in days, some in months.

Spider plant is a good option, if you trim off the fronds carrying the babies it will be mostly upright in form. And the babies will provide a series of next generation testing ground. Another one to try could be a leaf cactus, Christmas or Easter ones are both quite happy with fairly moist soil during growth, and will tolerate draught. The change of needs during the year would also give a nice set of data.

For a quick establishing plant, supermarket chives usually burst into new growth within a week of re-potting. Mint is another one that is roaring to grow in a new pot. Both are short lived indoors, but would provide good testing plants cheaply.

Would the system work if the plant is not in soil, but in a more coarse medium? I'm thinking of Orchids, that are very commonly bought as gifts or from supermarket, are delightful plants and often die waterlogged in their stylish cover pots.

Which brings up the next question, will the plants be in pots with drainage or not? Any water out of reach of the roots, or standing in the bottom of the container might complicate measuring up the actual moisture need of the rootball.

And finally, for testing purposes, would a toilet roll innard half buried in the soil work? I would think it would absorb the moisture and evaporate it off, and hopefully be sturdy enough to last a week or two. A row of freshly planted toilet rolls would look brilliant in any living room

Sorry for the long, layman ramble- I do find this idea fascinating and can see the need. There are a few people who are interested in plants but hesitate to get them if they can't be "in control" for any reason.

Welcome to the forum, @T_i_m

 

Hi Selleri and thanks for the reply and feedback. ;-)

Thanks for the info re some plants being a bit sensitive to being moved. It makes sense as their are living entities and so it makes sense they could be sensitive to their environment.

Re what constitutes 'too much' water for a potted plant. I get that some plants are very sensitive to excess water but outside those my rule-of-thumb for anything in a free draining pot is that any surplus simply drains though?

FWIW, my Begonia is in the plastic pot it came in from Homebase (not my first choice of supplier for such things but I was passing and the lady there seemed fairly interested to try to help me find something and offered the Begonia as the best they could offer at that time) and it's currently stood in a deep CD spindle case so I can 1) see the water level and 2) because it had a gully round the outer edge, drains any excess water away from the bottom of the pot and 3) that water then evaporates around the plant, giving it a bit of humidity?

Along with the other plant specific tips, the leaf cactus (cacti?) sound like they could be ok for as close to a fit-and-forget sort of solution I think this project may need (as you say, especially to provide a long term data-set). The goal (if there is one as such) is to initially see what range of 'moisture' measurements we might normally see from this type of solution (remore / wireless capacitive sensor > microcontroller, Home Automation solution etc) and once we can determine what level might be considered ideal, see how closely we can automagically hold the moisture at that level.

This is the display I see on my desktop (it could be a meter like that, or just the numbers etc ...


And if you click on that you get this ...
It's a bit noisy at the moment but that's part of the project, refining such things. It's also interesting to see that it thinks the moisture level has raised slightly early this morning but that could be the electronics and some temperature drift, something you could check against the temperature graph from the same area over the same period.
Now, in theory it would be possible to compensate for any temperature related drift in Home Assistant but 1) I don't know how (haven't looked) and 2) not sure it's relevant when the project is seen at the bigger picture level.

What I have configured though is at a value of 50% (that threshold can be changed in seconds) the system sends me an email from the Begonia saying 'Water me'. ;-)

OOI, when I first set-up the sensor I used dry air and a cup of water to determine what might constitute 100% dry and 100% wet. However, fully watered pot compound didn't output the same value as the water and fully dry soil would still read higher than air.

So I then re-engineered it (in the software) to change those end points to (hopefully) better reflect the real-world range a plant might want, where 100% should represent 'enough water' (not waterlogged) and 0% would be 'I desperately need watering' (not that it's dry etc). However, because it's quick and easy to change all of this, I'm aiming to make the range more pertinent.

Cheers, Tim

 

Hi @T_i_m

Well you sound light years ahead of us in the micro usage and though we have updated some of our projects to the ESP32 for its larger memory, we have still not utilzed its wifi, though have tried the odd wifi tutorial on it as featured on the Random Nerds site.

Same with the home autoamation, being the older generation and retired and not so mobile savvy, we still like to flick the odd light switch.

Your diy 3d printer sounds interesting, did you do a ytube or similar on the build ?
In the forums Hobby section we did ask about buying one as you can see in @Ademission recent post, feel free to add any comments.
3D Printing - Whats it all about?

 

Hi again Ricky,

I don't think I'm ahead on you re using WiFi on the ESP32's etc because Home Assistant makes it all so easy. ;-)

You run Home Assistant on say a Raspberry Pi (it's a downloadable and ready to boot image). Google 'home assistant' etc.

You then connect to it from your PC, laptop, tablet of smartphone over your LAN and sign in for the first time and do some basic wizard led setup.

Then you add the ESPHome integration (all menu type stuff) and then use the ESPHome wizard to create the code for your particular ESP32/8266. You then connect it via USB cable to the HA machine (RPi etc) and upload the code that allows the ESP to connect to your WiFi. Once you have done that once, you can put the ESP anywhere within range of your WiFi (even in a greenhouse etc) and be able to continue to use (sensors and outputs) and even re-program it over WiFi. ;-)

Once the ESP is producing a sensor or offering an output, those things 'appear' in Home Assistant and you can then reference them directly, (click 'On' on your 'Garden watering system', a relay driving a solenoid connected to your hose turns on) and put them on the desktop of the main system. You can also have several different users and multiple desktops and views for each, allowing some users to just view and others to change things etc.

It really is a fantastic system, especially so because it's free!

And given the cost of something like a Rasberry Pi is so low (compared with even the most basic of auto irrigation solutions etc), they are so small and use so little energy themselves, it really can be a good VFM solution, especially for those who are happy playing with a bit of tech. And given the rise in 'smart' solutions these days, even commercial addons can be available quite cheaply.

Cheers, Tim

p.s. I built the 3D printer with / for a mate (he bought a kit upon my recommendation on the grounds I helped him build it) and I eventually bought it off him. It's a MendelMax and I don't know what I would do without it now. It's still fascinating to me (after probably 10 years) to be able to think of something and be actually holding it in my hand a short while later! (Check out 'thingiverse' on the interwebs, loads of plant related things you can download and print there!). ;-)

 

Hi Tim,

Thanks for that info, did not realise that Home Assistant made wifi connection so easy, doing those Random Nerd code tutorials can be quiet heavy.
Random Nerd Tutorials | Learn ESP32, ESP8266, Arduino, and Raspberry Pi
Will certainly take a good look at HA, though generally find the Arduino /ESP32 a lot more practicable with its easy to use I/Os compared to the Rasp Pi.

Ah, thought you meant you had built a 3D printer from scratch, like some folk we know who made their own CNC machines using old printer slider rails etc.
Looks like that MedelMax is now on version 3 but at $1395 a bit different form the humble £217 Ender 3 V2 we were looking at ! any thoughts about the Ender?
Creality3D Ender3 V2 3D Printer

 

Hi Ricky,

Yes, Home Assistant vie the ESPHome addon allws this 'non-coder' (I'm really a hardware / IT support / electronics service guy) makes, given the availability of suitable library's, pretty easy to use. I'd say with programming the Arduino / ESP's using the Arduino IDE means you have to go down to a fairly low level, whereas when using HA as the main platform then it's all far simpler. Like, you don't actually see much in the way of the underlying code, just references to the bits that you can change / use. Google ESPHome for more detail on that (I can't include links here yet apparently). ;-)

I have used the Random Nerd Stuff quite a bit (and have bought a couple of his tutorials that as yet remain unread) and if I see something covered there I can usually be fairly confident it will work. ;-)

Re the printer ... yes, I guess I should have said I 'assembled the 3D printer' <g> but that said, I've also used ours to print all the plastic parts needed to build two more, assuming you don't require someone to also build the Arduino Mega, RAMPS i/o board and extrude my own ally sections from scratch to count as 'built'. <weg>


My mate wanted to get a 3D printer and at the time, commercially made versions were very expensive so a maker kit was the most logical way to reduce the cost. However, this was a very basic 'kit' involving the assembler to do a fair bit of work (over and above assembling it etc), especially re installing the Marlin Firmware and setting all the parameters etc (speeds, end-stops, PID control etc etc). However, a big part of my recommendation of going for the MendelMax over something commercial was that it was all open source and so we should be able to repair / upgrade it in the future (and we / I have). ;-)

I think the kit was around £350 when he bought it but we have spent a bit on it since. I now have it running as a tool. Think of something, design it in Sketchup, print, use. ;-)

Talking of that, I need to print some more cases (from Thingiverse) that hold the ESP8266 and the capacitive probe that make the plant moisture monitor a modular solution.

Cheers, Tim

 

Just on that Ricky, most of the places where we have fitted smart lights originally had pull cords to operate them so we now also have small Ikea wall switches as well. Eg, we can still turn the light on / off using the pull cords (although they are tied up so we don't turn them off by mistake as a reflex action) but now we either use the small wireless remote (that is held into the wall mount with magnets so can be removed if required) and can be operated with an elbow and because it's battery operated, isn't an electrocution risk (as would be a wall switch in a bathroom / toilet / kitchen etc).

The same applies for the hall / landing other than they are now more typically operated by a tiny battery powered (Zigbee standard) PIR sensor.

The front and rear lobby lights still have the std wall switches but we never touch those as the lights are turned on automatically at sunset and off at sunrise.

So we rarely use the mobiles to manage such things, although I did yesterday when taking to daughter on our Portal(s) and the curtains closed when it was still reasonably light outside so I grabbed the Mrs phone and opened them again. Had I been sitting near my desk I could equally have pressed the (universal Zigbee, programmed in HA to do the curtains) remote or clicked on the button on the Home Assistant desktop. I could also have got up and pressed the button on the std Swish electric curtain box that I've modified to make 'smart' using an ESP32 in HA (after the inbuilt LCD timer screen failed)). ;-)

I now consider my Home Assistant system along with my Leatherman pocket multitool, my Garmin GPS's and my 3D printer as things I really wouldn't want to be without. ;-)

Being able to say turn on a plant irrigation system, for 10 minutes, IF the ground moisture level is below a certain level AND IF it's between certain hours AND IF it's below a certain temperature AND below a certain humidity and it IS Thursday, all from drop down menus, a very cool thing. ;-)

Cheers, Tim

 

Hi ricky101 and T_i_m,

ricky101, did you every buy the 3D printer?

Just been reading your posts and it's great that both of you are pursuing a similar course with the small micro boards. I've used Arduino for some years now but my last few projects have used the ESP8266 and ESP32 and I used the Arduino IDE which is good enough for most projects. I program in C. Before all this I used a lot of PIC microcontrollers both at work and home. Before the PICS, other microprocessors and microcontroller going back to the original 6800, 6502 etc. Lately I've been playing with large colour matrix displays fed serially from ESP8266. I'm very interested in how you are sensing moisture in the soil of potted plants and how accurate it is? Could be an R & D project in its own right.

Keep up the good work.

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