houseplant

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Fytó pet plant

2025 Pet Hacks Contest: Fytó – Turn Your Plant Into A Pet

May 27, 2025 by 2 Comments

This entry into the 2025 Pet Hacks Contest is about bringing some fun feedback to normally silent plants. Fytó integrates sensors and displays into a 3D printed planter. The sensors read the various environmental and soil conditions that the plant is experiencing, and give you feedback about them via a series of playful expressive faces that are displayed on the screen embedded in the planter.

At the core of the Fytó is a Raspberry Pi Zero 2 W, which has plenty of power to display the animations while also being small enough to easily fit inside the planter without it growing in size much more than a normal planter would be. The sensors include a capacitive soil moisture sensor, a temperature sensor, and a light-dependent resistor. These sensors all provide analog outputs to relay their measurements and so there was an ADS1115 analog-to-digital converter board also included as the Raspberry Pi doesn’t have the required analog pins to communicate with them.

The fun animated faces are displayed with a 2-inch LCD display embedded in the planter. A small acrylic cover is placed in front of the LCD to help ease the transition from the printed planter to the internally mounted screen. The temperature and light sensors were also placed in openings around the planter to ensure they could get good environmental readings. There are six expressions the Fytó can express based on its sensor readings, ranging from happy when all the readings are in a good zone, to thirsty if it needs water or freezing when it’s too cold. Be sure to check out the other entries in the 2025 Pet Hacks Contest.

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Ultra-Low Power Soil Moisture Sensor

March 18, 2025 by 13 Comments

Electricity can be a pretty handy tool when it stays within the bounds of its wiring. It’s largely responsible for our modern world and its applications are endless. When it’s not running in wires or electronics though, things can get much more complicated even for things that seem simple on the surface. For example, measuring moisture in soil seems straightforward, but corrosion presents immediate problems. To combat the problems with measuring things in the natural world with electricity, [David] built this capacitive soil moisture sensor which also has the benefit of using an extremely small amount of energy to operate.

The sensor is based on an STM32 microcontroller, in this case one specifically optimized for low-power applications. The other low-power key to this build is the small seven-segment e-ink display. The segments are oriented as horizontal lines, making this a great indicator for measuring a varying gradient of any type. The microcontroller only wakes up every 15 minutes, takes a measurement, and then updates the display before going back to sleep.

To solve the problem resistive moisture sensors have where they’re directly in contact with damp conditions and rapidly corrode, [David] is using a capacitive sensor instead which measures a changing capacitance as moisture changes. This allows the contacts to be much more isolated from the environment. The sensor has been up and running for a few months now with the coin cell driving the system still going strong and the house plants still alive and properly watered. Of course if you’re looking to take your houseplant game to the next level you could always build a hydroponics system which automates not only the watering of plants but everything else as well.