Circuit Documentation

Summary

This circuit is designed to monitor soil moisture levels and control a water pump and a fan based on the sensor readings. It uses an ESP32 microcontroller to read data from a SparkFun Soil Moisture Sensor and a DHT11 Humidity and Temperature Sensor. The ESP32 also controls a 2-channel relay to power a 5V mini water pump and a 40mm 12V fan. The system status is displayed on a 1.3" OLED display module. The circuit is powered by a 12V battery, and the ESP32 is interfaced with various components through its GPIO pins.

Component List

• Battery 12V: Provides the power source for the circuit.
• SparkFun Soil Moisture Sensor: Measures the moisture level in the soil.
• ESP32 (30 pin): Acts as the central microcontroller unit to process sensor data and control peripherals.
• USB Cable: Used to program the ESP32 and provide a serial communication interface.
• 5V Mini Water Pump: Pumps water when activated by the relay.
• 2-Channel Relay: Controls the power to the water pump and the fan.
• 1.3" OLED Display Module: Displays sensor readings and system status.
• 40mm Fan 12V: Provides air circulation when activated by the relay.
• DHT11 Humidity and Temperature Sensor: Measures ambient humidity and temperature.

Wiring Details

Battery 12V

• + to 40mm Fan 12V +12V
• - to 40mm Fan 12V -12V, ESP32 GND

SparkFun Soil Moisture Sensor

• VCC to ESP32 3V3
• GND to ESP32 GND
• SIG to ESP32 D34

ESP32 (30 pin)

• GND to 40mm Fan 12V -12V, DHT11 Sensor GND, SparkFun Soil Moisture Sensor GND, 2-Channel Relay GND, 1.3" OLED Display Module GND, 5V Mini Water Pump negative pin
• Vin to 40mm Fan 12V +12V
• 3V3 to DHT11 Sensor VDD, SparkFun Soil Moisture Sensor VCC, 2-Channel Relay VCC, 1.3" OLED Display Module VCC
• D34 to SparkFun Soil Moisture Sensor SIG
• D32 to 1.3" OLED Display Module CLK
• D33 to 1.3" OLED Display Module MOSI
• D25 to 1.3" OLED Display Module RES
• D27 to 1.3" OLED Display Module DC
• D14 to 1.3" OLED Display Module CS
• D23 to 2-Channel Relay IN1
• D22 to 2-Channel Relay IN2
• D15 to DHT11 Sensor DATA

5V Mini Water Pump

• positive pin to 2-Channel Relay NO
• negative pin to ESP32 GND

2-Channel Relay

• NC (Not Connected)
• COM (Common connection for relay switches)
• NO to 5V Mini Water Pump positive pin
• VCC to ESP32 3V3
• IN1 to ESP32 D23
• IN2 to ESP32 D22
• GND to ESP32 GND

1.3" OLED Display Module

• CS to ESP32 D14
• GND to ESP32 GND
• VCC to ESP32 3V3
• CLK to ESP32 D32
• MOSI to ESP32 D33
• RES to ESP32 D25
• DC to ESP32 D27

40mm Fan 12V

• +12V to Battery 12V +
• -12V to ESP32 GND

DHT11 Humidity and Temperature Sensor

• VDD to ESP32 3V3
• DATA to ESP32 D15
• GND to ESP32 GND

Documented Code

ESP32 Microcontroller Code (sketch.ino)

void setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}

2-Channel Relay Microcontroller Code (sketch.ino)

void setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}

Note: The provided code for the microcontrollers is a template and does not contain any functional code. It needs to be implemented according to the circuit's requirements.