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Pixie was a project developed with the intention of making the plants we have at home more interactive, since for most people one of the challenges of having a plant at home is to know how to take care of it, how often we water, when and how much sun is enough, etc. While sensors work to obtain plant data, a LED display, purposely pixelated (hence the name Pixie), displays basic expressions that indicate the state of the plant, such as joy while it is being watered or sadness if the temperature is too high, indicating that it should be taken to a cooler place. To make the experience even more interesting, other sensors such as presence, touch and luminosity have been added, translating into other expressions that make it seem that you now have a virtual pet to take care of.

The project has several parameters where it is possible to customize the limits and needs of each case, considering the diversity of plants as well as sensors of different brands. As we know, there are plants that need more sun or water while others can live with fewer resources, such as cacti for example, in cases like this, having parameters is a must have. Throughout this article, I will present the operation and an overview about how to build a Pixie using a little knowledge of electronics, components easily found in the market and a 3d printed case.

Although it’s a fully functional project, there are possibilities of customization and improvements that will be presented at the end of the article. I will be glad to answer any question about the project here in the comments or directly to my email or Twitter account.

All components are easily found in specialized stores or websites.

1 MCU ESP32 (ESP8266 can be used or even an Arduino Nano if you do not want to send data over the internet)
I’ve used this model for the project
1 LDR 5mm GL5528
1 PIR element D203S or similar (it is the same sensor used in SR501 or SR505 modules)
1 DHT11 Temperature sensor
1 Soil moisture sensor
Prefer using capacitive soil sensor instead of resistive, this video explains well why
1 Led Matrix 8x8 with integrated MAX7219
I used this model, but it could be any similar
1 Resistor 4.7 kΩ 1/4w
1 Resistor 47 kΩ 1/4w
1 Resistor 10 kΩ 1/4w

3d Printer
Soldering Iron
Cutting Pliers
Wires for circuit connection
USB cable for power supply”

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