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Show HN: Xenolab – Rasp Pi monitor for my pet carnivourus plants

• 52 Comments
• You have resistive soil sensors. I'd recommend replacing them with capacitive sensors - they are much more reliable.
  A good video with a short intro why resistive sensors suck, and what to pay attention to with capacitive sensors: https://www.youtube.com/watch?v=IGP38bz-K48

  By orphea a day ago

• agree with dis ^

  By AtomicByte 7 hours ago

• I bought a Venus fly trap about 10 years ago, and recall wanting to stick some RGB LEDs on an “Arduino or something” to get them to turn on and off in sync with the sun. I was hung up on the idea that this is in my windowsill, so the data on sunrise and sunset I could get from a photoresistor. It would also monitor moisture.
  This is so cool!

  By floam 2 days ago

• This setup would take like 10 minutes in Home Assistant.

  By chneu a day ago

• OP proceeds to spend 6 months worth of evenings and weekends learning basic electronics, Arduino, and Home Assistant installation and admin - to get to the stage where they can do this in 10 minutes.

  By bigiain a day ago

• I need this! I am struggling to grow carnivorous plants in New Zealand. I think I am giving them what they supposedly need but I just can’t win.

  By teruakohatu 2 days ago

• Just to reiterate what's already been said - don't use tap water. We have a carnivorous plant expert/dealer local to us and he just collects and uses rainwater, as he says tap water will kill them.
  Simple waterbutt attached to the drain pipe off the guttering and you get infinite free water for them

  By darreninthenet a day ago

• Water butt (noun) - British: a large container for collecting or storing a liquid (such as rainwater)
  This is so much better than "rain barrel".

  By dfc a day ago

• Was told the same thing, but my tap water works fine. If it’s true that it’s harmful I’d like to see some science (even citizen science.) Pretty sure it’s a myth.

  By alecst a day ago

• It's water that builds up limescale that it's harmful for the carnivorous plants. The peat moss substrate that carnivorous plants like is acidic and the limescale neutralizes that.

  By spiorf 20 hours ago

• Plausible, perhaps -- is there any evidence?

  By alecst 20 hours ago

• Yes there is plenty of evidence that carnivorous plants die in alkaline or neutral soil conditions.
  Read literally any book about caring for them. They like acidic soil. Rain water is slightly acidic.
  It might take a year or more to kill a plant by slowly draining its soil of acidity. Just like it can take a year to kill a big plant via inadequate lighting.

  By Xss3 20 hours ago

• Probably depends on the location. I've had a bunch of carnivorous plants in Spain, not exactly great tap water, and killed a bunch of them before switching to purchased distilled water.

  By diggan a day ago

• Depends on your tap water. Hetch Hetchy water has worked perfectly for me for years.

  By teaearlgraycold a day ago

• Its the water. I have a ro/DI system and use that water. All of the cool low nutrients species have been living for years no problem.

  By nwellinghoff 2 days ago

• Where abouts in NZ are you? I'm currently based in Wellington and my Venus fly traps, sundew, and pitcher plants seem to be doing quite well on the windowsill.

  By PradeetPatel a day ago

• If it’s the water, could it help to let it stand for a while? I do that to get rid of the chlorine.

  By barbazoo 2 days ago

• Many American cities use chloramine, which requires something like Sodium thiosulfate, but then you're left with Ammonia, which may or may not be desired.

  By lagniappe a day ago

• The ammonia will gas off if you let it sit after adding. I used to use Camden tablets (sodium metabisulfate) to treat chloramine water (Philadelphia) for brewing beer.
  Beer yeast will make chloramine / chlorine water taste like plastic! Learned the hard way. :)

  By myvoiceismypass 14 hours ago

• I think it's something in our water, I have to give them purified water which I buy.

  By malux85 2 days ago

• That's cool, but I'm curious how you determine that the LED's output the right wavelengths for plant growth? I was under the impression you need specific types for grow lights and these look like standard off the shelf LEDs

  By dugite-code a day ago

• I dont, they are just off the shelf components, this is not a serious project, it is a toy that I used to relax away from work.

  By malux85 a day ago

• > this is not a serious project, it is a toy
  You call it "cutting-edge" in the README.

  By voytec a day ago

• Where? A: Just above the paragraph about not using it to monitor triffids.
  There are some hints here that this is just a bit of light-hearted fun.

  By malux85 19 hours ago

• > Where?
  At the top, just below[0] the title.
  Anyway, great project and worth pushing beyond being a "toy project" imo. But like few other commenters - seeing LEDs you used immediately rubbed me the wrong way.
  I tend to seed my peppers in Dec/Jan (in Central Europe), ~1.5-2 months before you would normally do it. Without proper growlights and FANs they would get too tall before releasing leaves and have "leggy", too thin stem, to be moved to windy outdoors in Apr/May. These kinds of plants grow too tall if they don't "detect" proper [sun]light and don't spawn leaves since there's no light required for photosynthesis at given height.
  My use-case (leggy, thin stems that break under outdoor wind) isn't translatable to yours but my point here is: having a set of dedicated red and blue LEDs with certain wavelenghts (red 630nm-660nm, blue 450-470nm, depending on plant species) is the key to emulate natural sunglight. Other wavelenghts are cool for decorative purposes but it's still "darkness" for plants. I used to buy small PCBs and LEDs dedicated for soldering together with reds and blues of different wavelenghts ratio one requires but nowadays I'm going mostly with ready-to-use grow lamps as I grow rather not that demanding plants.
  Your project is great, shows your dedication and already doesn't at all seem like a "toy project". I'd love to see it extended to different kinds of plants!
  [0] https://github.com/blackrabbit17/xenolab/blob/129af07788909e...

  By voytec 17 hours ago

• I have some venus fly traps, they are suspended from the side a of a fish tank with the bottom of their container in the (presumably nutritious for them) fish water. Unrelated to blackrabbit17s setup, home assistant controls the lights and pumps.

  By asmodeuslucifer 2 days ago

• > The Xenolab Rasp Pi Monitor is a cutting-edge, semi-autonomous biosurveillance module engineered for the precise care and observation of exotic carnivorous flora.
  This sounds very solarpunk mixed with cyberpunk. I love it.

  By SahAssar a day ago

• I'm just here to say kudos to your hardware integration build quality. I've worked on a few projects, and your setup looks VERY NICE. I would read a few blog articles if you posted about just your design and integration process.

  By danesparza 19 hours ago

• Thank you!
  This is my first project where I integrated many things together, and it went through a few iterations (I replaced the lights twice)
  I think the key was: patience
  There were many times where I didn’t have the right connections, or screws, or cables or I needed more diodes when I probably could have got away without it - things like this - where I refused to take a shortcut, ordered the part in the mail and waited, which often meant I couldn’t proceed - so “that’s enough today”

  By malux85 18 hours ago

• I can appreciate the engineering but damn this look extreme.
  My carnivorous plants are by the window and I water them once in a while, never had issue.
  I thought about automating water supply but even me, a geek, realized it would be a waste of time.

  By aucisson_masque 2 days ago

• I mean, it was pretty obvious from Xenolab Safety Directive 12.4B that this was not a purely pragmatic and generalised to fit everyone kind of project.

  By bigiain a day ago

• My cup runneth over

  By malux85 18 hours ago

• Hm, you cannot simulate sunlight at all with an RGB LED ring. You can create something that looks cool for our human eyes but the average plant wouldnt make it long beneath them because its basically always living in the dark; the important wavelengths are missing.
  This is also a huge problem for people having a terrarium with geckos or saurians - they see and need much different wavelengths than we humans do.
  I am no expert for carnivorous plants - maybe they are fine but seeing that there is no UV emitting part in the lighting setup, there may be an important part of the spectrum missing for the plants.

  By chris_engel a day ago

• From skimming Wikipedia it seems like most absorption happens in the blue range and a bit less in red, almost nothing inbetween at green. Most LEDs are blue with a phosphor, so you usually get more blue light than the rest already.
  But surely there are LEDs optimised for that task (Cannabis grow lights)

  By cenamus a day ago

• There are LEDs optimised for that purpose. Not strictly necessary though.
  Someone I know had a very successful indoor cannabis grow using nothing but a cool white outdoor LED panel light from the local hardware store.

  By ash_091 14 hours ago

• The lights beside it are grow lights to augment.

  By malux85 a day ago

• You might also be interested in this - https://docs.backyardbrains.com/retired/experiments/Plants_V... where they monitor the electrical spikes of the traps.
  You can also apparently electrically trigger the closing of fly trap - https://www.tandfonline.com/doi/full/10.4161/psb.2.3.4217

  By anfractuosity 2 days ago

• Great work! It would be interesting to have a side by side comparison with a plant grown without monitoring.

  By omneity 2 days ago

• Impressive work for monitoring some plants! I hope they don’t bite you :)

  By giuliomagnifico 2 days ago

• The “torque” of these plants is very low usually. You barely feel the pressure.
  Source: My finger, unscathed after an encounter with a Dionaea.

  By omneity 2 days ago

• A part of me really hopes to see this used as a prop in the upcoming Alien: Earth TV show.

  By cushychicken a day ago

• I had two carnivorous plants so far, but they all died after 3 months or so. I need to learn how to better care for them, cause I think they are so cool.

  By atum47 a day ago

• As others mentioned, try distilled/purified water. Also killed a bunch myself before switching to it.

  By diggan a day ago

• Some of them also hibernate so I do wonder how many people have thought their plant died when it was just hibernating. Lots of the sundews don’t require a hibernation period so if you want to start with easy plants that are carnivorous and also extremely beautiful go with Sundews!

  By lovehashbrowns a day ago

• this is super lit! i always mess up watering and stuff, so seeing you build all this around your plants kinda gives me ideas - you think all this tech actually changes how connected you feel to the whole growing thing?

  By gitroom a day ago

• It sits on my desk right next to where I work every day, and it looks kinda sci-fi,
  I was motivated by Star Trek a lot when I was very young, and having some futuristic bit of tech beside me while I work (that I created) reminds me that we are all working towards building that future, even just symbolically.
  Building this gave me utter joy at learning CAD, figuring out electronics problems, understanding difficulties 3D printers have, finding electronic components here in NZ, figuring out bugs while typing commands like “restart sunlight” was amusing.
  The final product is really just a byproduct and reminder, the primary source of joy is the act of creation

  By malux85 18 hours ago

• That’s really cool. Thanks for sharing.

  By cactusplant7374 2 days ago

• Very nice, the UI is super sleek :)
  Is the Pi 5 really necessary though, especially since it's one per plant? The Pi 4 would surely be up to the challenge of rendering that while using less power and would be cheaper.

  By moffkalast 20 hours ago

• Thank you!
  Originally, before I knew which plants I would use, I was going to use ML models to measure the surface area of the plants, and in earlier versions (before the camera) I had rotating, high polygon 3D models.
  So I threw a bit more hardware at it than it needed because I didn’t want to have my future ideas limited by hardware

  By malux85 19 hours ago

• What are those displays? Where can I get one?

  By troupo a day ago

• From the photos, they seem to be DFRobot displays[0] ($55). PiHut has one matching the description[1] but it comes with a camera and is pricy (~$107). Amazon have a cheaper clone-brand option[2] (~$37). Aliexpress also has a wealth of cheap options for '7" DSI 800x480' (~$40-50).
  [0] https://www.dfrobot.com/product-2193.html
  [1] https://thepihut.com/products/7-dsi-capacitive-touch-display...
  [2] https://www.amazon.co.uk/dp/B0B8Y81Y6S

  By zimpenfish a day ago

• Thank you!
  Now I'm itching to do something with them :)

  By troupo 19 hours ago