🌱 I Built a Plant Sensor That Tells Me When to Water It (ESP32)

In this video, we build a *clean, intentional ESP32-based plant sensor that measures soil moisture, ambient light, temperature*, and *humidity*, and provides immediate human feedback using an *RGB LED ring*.

When the plant needs water, the LED shows a warning color — and when we add water, it turns green, confirming the plant is happy again 🌱

This video focuses purely on the hardware foundation:

• Parts selection
• Circuit design
• ESP32 firmware
• Real-world plant testing

Under the hood, the firmware also publishes all sensor readings over *MQTT*, laying the groundwork for future automation and AI — which we’ll explore in a later video.

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ESP32 SMART PLANT SENSOR — PARTS LIST
(All components used in this build)

ESP32 Microcontroller
ESP32-WROOM-32E development module
https://amzn.to/3N9yHER

Breadboard (Prototype Build)
Full-size solderless breadboard
https://amzn.to/4jvf9Xk

Soil Moisture Sensor
Capacitive soil moisture sensor (analog output)
https://amzn.to/4spTR1s

Temperature & Humidity Sensor
DHT22 digital temperature + humidity sensor
https://amzn.to/3N652fM

Ambient Light Sensor (I²C)
BH1750 digital light sensor
https://amzn.to/4pvZicq

RGB Status Indicator
16 × WS2812B RGB LED ring
https://amzn.to/45MmOed

Logic Level Shifter (LED Data)
SN74AHCT125N (3.3V → 5V)
https://amzn.to/45828NI

USB-C Power Breakout
USB-C breakout board
https://amzn.to/4jvXUVU

Hook-Up Wire
22 AWG solid-core wire (breadboard-friendly)
https://amzn.to/3Nb00i4

Some links may be affiliate links. They help support the channel at no extra cost to you.

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ESP32 PLANT SENSOR — WIRING REFERENCE

All connections assume a standard ESP32 DevKit (ESP32-WROOM-32E)

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POWER CONNECTIONS

ESP32
• 5V / VIN → Power input (USB or regulated 5V)
• GND → Common ground

RGB LED Ring
• 5V → 5V supply
• GND → Shared ground with ESP32

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RGB LED RING (WS2812B)

• DIN → GPIO 5
• 5V → 5V supply (add 1000 µF capacitor across 5V/GND)
• GND → Shared ground
• 330–470 Ω resistor between ESP32 and DIN (recommended)

Note: The LED ring is mounted *vertically*, with LEDs facing outward for human feedback.

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TEMPERATURE & HUMIDITY SENSOR (DHT22)

• VCC → 3.3V (do NOT use 5V)
• DATA → GPIO 15
• GND → Ground
• 10 kΩ pull-up resistor between DATA and 3.3V

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AMBIENT LIGHT SENSOR (BH1750 – I²C)

• VCC → 3.3V
• GND → Ground
• SDA → GPIO 21
• SCL → GPIO 22

Important: BH1750 must be exposed to ambient light (do not recess behind plastic).

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SOIL MOISTURE SENSOR (CAPACITIVE)

• VCC → 3.3V
• GND → Ground
• AOUT → GPIO 34

Note: GPIO 34–39 are input-only and ideal for analog sensors.

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MQTT / FUTURE EXPANSION

• Sensor readings are published as JSON over MQTT
• Transport: Wi-Fi
• No hardware changes required for future AI integration

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QUICK PIN SUMMARY

RGB LED Data → GPIO 5
Temp / Humidity → GPIO 15
Light Sensor SDA → GPIO 21
Light Sensor SCL → GPIO 22
Soil Moisture → GPIO 34
Power → 5V / 3.3V
Ground → GND

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This is the first step toward a calm, extensible environmental sensing system — built intentionally, not rushed.

#ESP32 #IoT #SmartPlant #MQTT #Electronics #DIY #STEM #PlantCare #EmbeddedSystems