ESP32-Based Environmental Monitoring System with Multiple Sensors
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Circuit Documentation
Summary
The circuit in question is designed to interface with various sensors and modules through an ESP32 microcontroller. The ESP32 serves as the central processing unit, managing data from a DHT22 temperature and humidity sensor, an MQ-135 air quality sensor, a rain sensor, a water level sensor, a BH1750 light intensity sensor, and an HX711 bridge sensor interface. The circuit is powered through the ESP32's 3.3V pin, which supplies power to all other components. Ground connections are also centralized through the ESP32. Sensor data is collected via the ESP32's GPIO pins, with some sensors interfaced through analog pins and others through digital pins. The I2C protocol is used for communication with the BH1750 light sensor.
Component List
ESP32 (30 pin)
- Description: A microcontroller with Wi-Fi and Bluetooth capabilities, featuring a variety of digital and analog I/O pins.
- Pins: EN, VP, VN, D34, D35, D32, D33, D25, D26, D27, D14, D12, D13, GND, Vin, D23, D22, TX0, RX0, D21, D19, D18, D5, TX2, RX2, D4, D2, D15, 3V3
DHT22 (x2)
- Description: A digital temperature and humidity sensor with a single digital output.
- Pins: +, Out, -
MQ-135 SENSOR AIR QUALITY
- Description: An analog gas sensor for detecting a wide range of gases, including NH3, NOx, alcohol, benzene, smoke, and CO2.
- Pins: VCC, GND, A0, D0
HX711 - Bridge Sensor Interface
- Description: A precision 24-bit analog-to-digital converter (ADC) designed for weigh scales and industrial control applications to interface directly with a bridge sensor.
- Pins: E+, E-, A-, A+, B-, B+, GND - GROUND, DATA (OUT), SCK - CLOCK (IN), 3.3/3.5V Supply
RAIN SENSOR
- Description: A sensor that detects rain by measuring the resistance between two pads, which changes with moisture.
- Pins: AO, DO, GRD, VCC
Water Level Sensor
- Description: A sensor that detects the level of water by measuring the resistance between multiple exposed traces at different heights.
- Pins: SIG, VCC, GND
BH1750
- Description: A digital light intensity sensor that communicates over the I2C bus.
- Pins: VCC, GND, SCL, SDA, ADDR
Wiring Details
ESP32 (30 pin)
- 3V3: Connected to the power supply pins (+) of both DHT22 sensors, VCC of MQ-135, BH1750, RAIN SENSOR, Water Level Sensor, and 3.3/3.5V Supply of HX711.
- GND: Connected to the ground pins (-) of both DHT22 sensors, GND of MQ-135, BH1750, RAIN SENSOR, Water Level Sensor, and GND - GROUND of HX711.
- D34: Connected to A0 of MQ-135 SENSOR AIR QUALITY.
- D35: Connected to AO of RAIN SENSOR.
- D33: Connected to SIG of Water Level Sensor.
- D12: Connected to DATA (OUT) of HX711 - Bridge Sensor Interface.
- D13: Connected to SCK - CLOCK (IN) of HX711 - Bridge Sensor Interface.
- D22: Connected to SCL of BH1750.
- D21: Connected to SDA of BH1750.
- D5: Connected to Out of one DHT22 sensor.
- D4: Connected to Out of the other DHT22 sensor.
DHT22 (x2)
- +: Connected to 3V3 of ESP32.
- Out: One connected to D5 and the other to D4 of ESP32.
- -: Connected to GND of ESP32.
MQ-135 SENSOR AIR QUALITY
- VCC: Connected to 3V3 of ESP32.
- GND: Connected to GND of ESP32.
- A0: Connected to D34 of ESP32.
HX711 - Bridge Sensor Interface
- 3.3/3.5V Supply: Connected to 3V3 of ESP32.
- GND - GROUND: Connected to GND of ESP32.
- DATA (OUT): Connected to D12 of ESP32.
- SCK - CLOCK (IN): Connected to D13 of ESP32.
RAIN SENSOR
- VCC: Connected to 3V3 of ESP32.
- GRD: Connected to GND of ESP32.
- AO: Connected to D35 of ESP32.
Water Level Sensor
- VCC: Connected to 3V3 of ESP32.
- GND: Connected to GND of ESP32.
- SIG: Connected to D33 of ESP32.
BH1750
- VCC: Connected to 3V3 of ESP32.
- GND: Connected to GND of ESP32.
- SCL: Connected to D22 of ESP32.
- SDA: Connected to D21 of ESP32.
Documented Code
No code has been provided for the microcontrollers in the circuit. Therefore, this section is currently empty. When code becomes available, it should be documented here with appropriate comments and explanations of its functionality.