the PCB without the case on, showing the screen, battery, and removable sensor

2023 Hackaday Prize: A Reusable Plant Monitor

August 20, 2023 by Matthew Carlson 6 Comments

[Ovidiu] cares for their house plants, trying to dial in the perfect soil humidity and light levels. However, many cheap monitors tend to rust after a few weeks of sitting in a damp, slightly acidic environment. By creating a custom plant monitor with a removable probe, not only can [Ovidiu] integrate better with their Home Assistant setup, but it will also be less wasteful.

The build starts with an ESP32-S3, a TP4056 charging circuit, a small e-ink display, and an AHT20 IC for air humidity and temperature. The ESP32 reads the probe using the capacitance measuring devices for touchpads built into the chip. Or course, a 450mAh battery provides a battery life of about 11 days. The probe is just a bare PCB with a connector at the top, making them cheap and easy to swap. They included pads on the probe for a thermistor for reading soil temperature, but this is optional. A handsome 3D-printed case wraps it all up nicely.

Continue reading “2023 Hackaday Prize: A Reusable Plant Monitor” →

close-up image of a philodendron houseplant with electrodes attached, connected to a robot arm holding a machete

(Mostly) Harmless Houseplant Wields Machete

October 6, 2022 by Dave Walker 27 Comments

In a straight fight between a houseplant and a human, you might expect the plant to be at a significant disadvantage. So [David Bowen] has decided to even the odds a little by arming this philodendron with a robot arm and a machete.

The build is a little short on details but, from the video, it appears that adhesive electrodes have been attached to the leaves of the recently-empowered plant and connected directly to analog inputs of an Arduino Uno. From there, the text tells us that the signals are mapped to movements of the industrial robot arm that holds the blade.

It’s not clear if the choice of plant is significant, but an unarmed philodendron appears to be otherwise largely innocuous, unless you happen to be a hungry rodent. We hope that there is also a means of disconnecting the power remotely, else this art installation could defend itself indefinitely! (or until it gets thirsty, at least.) We at Hackaday welcome our new leafy overlords.

We have covered the capabilities of plants before, and they can represent a rich seam of research for the home hacker. They can tell you when they’re thirsty, but can they bend light to their will? We even held a Plant Communication Hack Chat in 2021.

Continue reading “(Mostly) Harmless Houseplant Wields Machete” →

Can Plants Bend Light To Their Self-Preserving Will?

March 4, 2021 by Kristina Panos 33 Comments

It does sound a bit silly — the idea that given enough time, a plant could influence the order of hardware-generated random numbers in order to get enough light to survive. But not so silly that [DeckerM] couldn’t wait to try it out after seeing a short clip about an unpublished study done at Princeton’s Engineering Anomalies Research (PEAR) lab that came to this very conclusion. The actual verbatim conclusion from the clip: “It’s as though life itself – even life or consciousness in something as simple as a house plant, bends probability in the physical world in the direction of what it needs, in the direction of its growth and evolution.”

The idea is this: a plant is made to suffer by languishing in the corner of a windowless room. The room has exactly one light in the middle of the ceiling — a repositionable spotlight of sorts that can only shine into any of the four corners and is controlled by a random number generator. A set of dividers ensure that none of the light leaks out of the quadrant and into any of the others.

[DeckerM]’s recreation of this experiment is much more practical. It’s essentially a little plywood cabinet with four open partitions and a ceiling. Each quadrant has a grow light strip planted in the corner, and all the wires are run through the top, where each has been stripped of its pesky power-governing controller and rewired to go straight into a smart plug. [DeckerM] is using a hardware RNG hosted on a Raspberry Pi, which is running a Python script that takes numbers from the RNG that corresponds to one of the quadrants, and then lights that quadrant.

And the results? They don’t really support the PEAR study’s bold conclusion unless viewed in small sample sizes, but [DeckerM] isn’t giving up that easily. Since the paper is unpublished, there are a lot of unanswered questions and juicy variables to play with, like the type, number, and age of the plants used. We’re excited to see if [DeckerM] can shed some light on plant psychokinesis.

Interested in portable plant propagation? A sunny location is usually ideal, but this all-in-one solution can take care of the rest.

Hearing Plants Giggle Is Just As Creepy As You Think

March 18, 2020 by Tom Nardi 13 Comments

While best known for Charlie and the Chocolate Factory, Roald Dahl wrote quite a few similarly oddball stories in his time. One of them, The Sound Machine, is about a device that allowed the user to hear the anguished screams of trees as they were cut down. Sounds kind of weird to us, but [Roni Bandini] liked the idea so much he decided to build his own version.

Now to be fair, the device doesn’t only scream in pain. In fact, most of the time it should be emitting laughs and happy noises. Using a moisture sensor driven into the soil of a plant’s pot, the device uses these audio cues to tell you the relative health of your leafy friend. So assuming you’ve got any sort of green thumb at all, things should be fine.

But once the soil gets too dry and the device determines the plant is in “pain”, things take a turn for the worse. We suppose it doesn’t technically scream out so much as grunt like a zombie, but it’s still not a noise we’d want to hear while walking through the house at night. Luckily, it seems you need to hit the button on the front of the 3D printed enclosure to get it to play the appropriate sound track from its DFPlayer module.

Personally we’d rather build something that makes sure the plants are being taken care of automatically than a gadget that cries out in anguish to remind us that we don’t know what we’re doing. But hey, everyone gets inspired in their own way.

Continue reading “Hearing Plants Giggle Is Just As Creepy As You Think” →

Tired Of Killing Houseplants? Try Using WiFi.

December 17, 2018 by Ted Yapo 50 Comments

Here at Hackaday, we have to admit to neglecting a few houseplants in our time. Let’s face it… a cold, hard, thinking machine can care for our green friends better than you can. Why not team up? [cabuu]’s WiFi-enabled soil moisture sensor will do the trick in case you, too, want happy plants.

This is one of those projects which would have been much more difficult even five years ago, and really shows how lucky we are to have accessible technology at our fingertips. It’s conveniently constructed from off-the-shelf electronics modules, and nestled inside a 3D-printed case. The design is attractive as well as functional, showing the status LED and allowing access to the USB charging port.

The brain is a WeMos D1 mini, while a D1 battery shield and 14500 Li-ion battery supplies power. A key point of this build is the use of a capacitive moisture sensor, which doesn’t suffer the same long-term corrosion problems that destroy cheaper resistive probes. And no project is complete without an LED, so a WS2812 shows green for good, red for dry and blue for too wet. To extend battery life, the sensor supports a sleep mode, which tests the soil periodically, and presumably disables the LED.

Of course, if you’re a habitual plant-neglector, simply having a moisture probe won’t help; those can be as easy to ignore as the plant itself. That’s where WiFi comes in. [cabuu] wrote a Blynk app to monitor the sensor on a smartphone. The app shows current moisture levels and allows you to change the wet and dry warning thresholds. When the reading exceeds these levels, the app notifies you — this feature is the one that will keep your plants around.

Continue reading “Tired Of Killing Houseplants? Try Using WiFi.” →

TerraDome Gives Plants And Dinosaurs A New Home

June 22, 2018 by Sven Gregori 1 Comment

Housing exotic plants or animals offer a great opportunity to get into the world of electronic automation. When temperature, light, and humidity ranges are crucial, sensors are your best friend. And if woodworking and other types of crafts are your thing on top, why not build it all from scratch. [MagicManu] did so with his Jurassic Park themed octagonal dome built from MDF and transparent polystyrene.

With the intention to house some exotic plants of his own, [MagicManu] equipped the dome with an Arduino powered control system that regulates the temperature and light, and displays the current sensor states on a LCD, including the humidity. For reasons of simplicity regarding wiring and isolation, the humidity itself is not automated for the time being. A fan salvaged from an old PC power supply provides proper ventilation, and in case the temperature inside the dome ever gets too high, a servo controlled set of doors that match the Jurassic Park theme, will automatically open up.

[MagicManu] documented the whole build process in a video, which you can watch after the break — in French only though. We’ve seen a similar DIY indoor gardening project earlier this year, and considering its simple yet practical application to learn about sensors, plus a growing interest in indoor gardening itself (pun fully intended), this certainly won’t be the last one.
Continue reading “TerraDome Gives Plants And Dinosaurs A New Home” →

Rotating Plants For Time-Lapse Purposes

September 12, 2014 by Matt Terndrup 13 Comments

Automating the growing process of plants and vegetables is an increasing trend among gardening enthusiasts and hobbyists. It’s no surprise, either, with microcontrollers, moisture sensors, Co2 detectors, and even time-lapse cameras with rotating wooden rigs that are in the hands of millions of amateur gardeners around the world.

This project by [Liz] helps to document the sprouting process of her tiny grapefruit bonsai tree that started to flourish at her apartment in Chicago.

Similar rigs can be used for practically any type of indoor plant. They can also be modified to move the plants and vegetables depending on how much light they are getting. Even further, just add some code to splice the photographs together and you’ve got yourself a custom setup that can produce animated GIF files to be uploaded easily to the internet. Pages and pages of happy and healthy growing plants unearthing themselves from the ground up would be pasted all over the web showing the entire sprouting process. An example video of this by [Liz] is embedded below.

Continue reading “Rotating Plants For Time-Lapse Purposes” →