Magic Pot 🪴

A smart plant monitor built on the ESP8266. It reads soil moisture and shows a face on a small OLED screen — happy when the soil is good, sad when it is too dry or too wet. When the plant gets dry, a short melody plays as an alert.

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How it works

The soil moisture sensor sends a value from 0 to 100%.

Moisture	State	Face	Buzzer
0 – 30%	DRY	Sad droopy eyes, frown, inverted screen	Plays a melody for 5 seconds
31 – 69%	OK	Closed ^^ eyes, gentle smile	Silent
70 – 100%	WET	Big shiny eyes, smile, water drops	Silent

The face blinks every 3.5 seconds regardless of state.

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Hardware

Part	Details
Microcontroller	ESP8266 NodeMCU v3 (CH340)
Display	SSD1306 OLED 128x64, I2C (0x3C)
Moisture sensor	Analog output connected to A0
Buzzer	Connected to GPIO12

Wiring

Moisture sensor AO  -->  A0
Buzzer              -->  GPIO12
OLED SDA            -->  D2 (GPIO4)
OLED SCL            -->  D1 (GPIO5)
OLED VCC            -->  3.3V
OLED GND            -->  GND

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Libraries required

Install these through the Arduino Library Manager:

• Adafruit SSD1306
• Adafruit GFX Library

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Setup

1. Open main/main.ino in the Arduino IDE.
2. Select board: NodeMCU 1.0 (ESP-12E Module).
3. Install the libraries listed above.
4. Upload and open the Serial Monitor at 9600 baud to see live readings.

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Adjusting thresholds

At the top of main.ino:

#define THRESHOLD_DRY 30   // below this = DRY
#define THRESHOLD_WET 70   // above this = WET

Change these values to match your plant and soil type.

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Serial output

Every second, a line like this is printed:

Moisture: 45%  |  Raw: 563  |  Level: OK