# ESP32 Weather Station Schematics

## Wiring Diagram

### ESP32 Pin Connections

```
ESP32 Development Board
┌─────────────────────────────────────┐
│                                     │
│  3V3  ──┐                          │
│  GND  ──┼───┐                      │
│  GPIO2 ──┘   │                      │
│             │                      │
│  GPIO4 ──────┼─── DHT11 Sensor      │
│             │   ┌─────┐            │
│  GPIO21 ─────┼───│ SDA │            │
│             │   │     │            │
│  GPIO22 ─────┼───│ SCL │            │
│             │   └─────┘            │
│  GPIO34 ─────┼─── Rain Sensor       │
│             │                      │
│  GPIO35 ─────┼─── LDR               │
│                                     │
│  VIN  ──┐                          │
│  GND  ──┼───┐                      │
│         │   │                      │
└─────────┘   │                      │
              │                      │
              ▼                      ▼
         Power Supply              Status LED
```

### Detailed Component Connections

#### DHT11 Temperature & Humidity Sensor
```
DHT11 Sensor
┌───────┐
│  1    │─── +3.3V
│  2    │─── GPIO4 (Data)
│  3    │─── (Not Connected)
│  4    │─── GND
└───────┘

Pinout (front view):
┌─────────┐
│  •  •  • │  ← Pins 1-4
└─────────┘
```

#### BMP180 Pressure Sensor (I2C)
```
BMP180 Sensor
┌─────────────┐
│ VIN   ─────┼─── +3.3V
│ GND   ─────┼─── GND
│ SDA   ─────┼─── GPIO21
│ SCL   ─────┼─── GPIO22
└─────────────┘
```

#### Rain Sensor Module
```
Rain Sensor Module
┌─────────────┐
│ VCC  ───────┼─── +3.3V
│ GND  ───────┼─── GND
│ AO   ───────┼─── GPIO34 (Analog)
│ DO   ───────┼─── (Not Connected)
└─────────────┘
```

#### LDR (Light Dependent Resistor)
```
LDR Circuit
┌─────────┐    ┌─────────┐
│ 3.3V    │    │         │
│         │    │   LDR   │
│   ┌─────┼────┼─────┐   │
│   │     │    │     │   │
│   ▼     │    │     ▼   │
│ 10kΩ    │    │         │
│ Resistor│    │         │
│   │     │    │         │
│   └─────┼────┼─────┐   │
│         │    │     │   │
│ GND     │    │     │   │
└─────────┘    │ GPIO35│   │
               │       │   │
               └───────┼───┘
                       │
                      GND
```

#### LED Status Indicator
```
LED Circuit
┌─────┐    ┌─────────┐
│3.3V │    │         │
│     │    │   LED   │
│ ┌───┼────┼─────┐   │
│ │   │    │     │   │
│ ▼   │    │     ▼   │
│220Ω │    │         │
│Res  │    │         │
│ │   │    │         │
│ └───┼────┼─────┐   │
│     │    │     │   │
│GPIO2│    │     │   │
└─────┼────┼─────┼───┘
      │    │     │
      └────┼─────┘
           │
          GND
```

## Complete Circuit Schematic

```
                    +3.3V
                      │
                      ├───────────────────┐
                      │                   │
                      │                   ▼
                      │               ┌─────────┐
                      │               │  DHT11  │
                      │               │  Sensor │
                      │               └─────┬───┘
                      │                     │
                      │                     ▼
                      │                   GPIO4
                      │                     │
                      │                     │
                      │                     │
                      │                     ▼
                      │                   GPIO21
                      │                     │
                      │                     ▼
                      │               ┌─────────┐
                      │               │ BMP180  │
                      │               │ Sensor  │
                      │               └─────┬───┘
                      │                     │
                      │                     ▼
                      │                   GPIO22
                      │                     │
                      │                     │
                      │                     │
                      │                     ▼
                      │                   GPIO34
                      │                     │
                      │                     ▼
                      │               ┌─────────┐
                      │               │  Rain   │
                      │               │ Sensor  │
                      │               └─────┬───┘
                      │                     │
                      │                     │
                      │                     │
                      │                     │
                      │                     ▼
                      │                   GPIO35
                      │                     │
                      │                     ▼
                      │               ┌─────────┐
                      │               │  LDR    │
                      │               │ Circuit │
                      │               └─────┬───┘
                      │                     │
                      │                     │
                      │                     │
                      │                     ▼
                      │                   GPIO2
                      │                     │
                      │                     ▼
                      │               ┌─────────┐
                      │               │  LED    │
                      │               │ Circuit │
                      │               └─────┬───┘
                      │                     │
                      │                     │
                      │                     ▼
                      │                   ┌─────────┐
                      │                   │  LCD    │
                      │                   │Display  │
                      │                   │ (I2C)   │
                      │                   └─────┬───┘
                      │                     │
                      │                     │
                      │                     ▼
                      │                   ┌─────────┐
                      └───────────────────┤   GND   │
                                        └─────────┘
```

## Power Distribution

```
Power Supply (USB 5V or External 5V)
┌─────────────────────────────────────┐
│                                     │
│  +3.3V ──────────────────────────────┼─── DHT11 VCC
│  (from ESP32 regulator)             │
│                                     ├─── BMP180 VCC
│                                     ├─── Rain Sensor VCC
│                                     └─── LDR Circuit VCC
│                                     │
│  GND ────────────────────────────────┼─── All GND connections
│                                     │
└─────────────────────────────────────┘
```

## Bill of Materials

### Components Required
1. **ESP32 Development Board** - 1x
2. **DHT11 Temperature & Humidity Sensor** - 1x
3. **BMP180 Pressure Sensor** - 1x
4. **Rain Sensor Module** - 1x
5. **LDR (Light Dependent Resistor)** - 1x
6. **LED (5mm, any color)** - 1x
7. **Resistors**:
   - 220Ω (for LED) - 1x
   - 10kΩ (for LDR pull-down) - 1x
8. **Breadboard** - 1x
9. **Jumper Wires** - Multiple

### Optional Components
- **External Power Supply** (5V, 1A) - For standalone operation
- **Project Enclosure** - For protection
- **PCB** - For permanent installation

## Assembly Instructions

### Step 1: Power Connections
1. Connect ESP32 to USB power
2. Verify 3.3V output from ESP32
3. Connect all VCC pins to appropriate power sources

### Step 2: I2C Bus Setup
1. Connect GPIO21 to all SDA pins
2. Connect GPIO22 to all SCL pins
3. Add pull-up resistors if needed (usually built-in to modules)

### Step 3: Digital Sensors
1. Connect DHT11 data pin to GPIO4
2. Connect LED circuit to GPIO2
3. Connect LDR circuit to GPIO35

### Step 4: Analog Sensors
1. Connect rain sensor analog output to GPIO34
2. Ensure proper grounding for analog circuits

### Step 5: Testing
1. Test each sensor individually
2. Verify LCD display operation
3. Check MQTT connectivity
4. Validate complete system operation

## Troubleshooting Guide

### Common Issues
- **I2C Communication**: Check SDA/SCL connections and addresses
- **Power Issues**: Verify voltage levels and current capacity
- **Sensor Readings**: Check pin assignments and wiring
- **LCD Display**: Verify I2C address (usually 0x27)

### Measurement Points
- **3.3V Rail**: Should be stable at 3.3V
- **I2C Signals**: Should show clear clock and data transitions
- **Analog Inputs**: Should vary with sensor changes
- **Digital Inputs**: Should show clear HIGH/LOW states