# Solar + Battery Powered Weather Station Schematics

## Complete System Overview

```
Solar Panel (6V 2W)
    │
    ├───[Schottky Diode 1N5817]──┐
    │                            │
    ▼                            ▼
TP4056 Charging Module        18650 Battery
    │                            │
    ├───[Protection PCB]─────────┘
    │
    ▼
3.3V Buck Converter
    │
    ▼
Wemos D1 Mini + Sensors
```

## Detailed Circuit Diagrams

### Solar Charging Circuit
```
Solar Panel (6V 2W)
┌─────────────────┐
│ +               │
│                 │
│ -               │
└─────┬───────────┘
      │
      ├──[1N5817 Schottky Diode]──┐
      │                           │
      ▼                           ▼
┌─────────────────┐        ┌─────────────────┐
│ IN+             │        │ +               │
│ TP4056          │        │ 18650 Battery   │
│ Charging        │        │ 3.7V 2500mAh    │
│ Module          │        │                 │
│ OUT+            │        │ -               │
└─────┬───────────┘        └─────────────────┘
      │                           │
      └───────────[Protection]────┘
```

### Battery Monitoring Circuit
```
18650 Battery (3.0V-4.2V)
    │
    ├───[100kΩ]───┐
    │             │
    ▼             ▼
   GND          A0 (Wemos D1 Mini)
    │             │
    └───[100kΩ]───┘
```

### Power Distribution Circuit
```
Battery Output (3.0V-4.2V)
    │
    ▼
┌─────────────────┐
│ IN              │
│ 3.3V Buck       │
│ Converter       │
│ OUT             │
└─────┬───────────┘
      │
      ├───3.3V──────────────────────────┐
      │                                 │
      ▼                                 ▼
┌─────────────────┐              ┌─────────────────┐
│ Wemos D1 Mini   │              │ Sensors         │
│                 │              │                 │
│ VCC             │              │ VCC             │
└─────────────────┘              └─────────────────┘
```

## Complete Weather Station Wiring

```
Wemos D1 Mini Pin Layout
┌─────────────────────────────────────┐
│ D1 (SDA) ──────────────────────┐    │
│ D2 (SCL) ──────────────────────┤    │
│ D3 (LDR) ──────────────────────┤    │
│ D4 (DHT11) ────────────────────┤    │
│ D5 (LED) ──────────────────────┤    │
│ A0 (Battery) ──────────────────┤    │
│                                │    │
│ 3V3 ───────────────────────────┼────┤
│ GND ───────────────────────────┼────┤
└────────────────────────────────┘    │
                                      │
┌─────────────────────────────────────┐
│ Component Connections               │
│                                     │
│ BMP180 Sensor                       │
│ ┌────────────────┐                  │
│ │ VIN ───────────┼─ 3.3V            │
│ │ GND ───────────┼─ GND             │
│ │ SDA ───────────┼─ D1              │
│ │ SCL ───────────┼─ D2              │
│ └────────────────┘                  │
│                                     │
│ DHT11 Sensor                        │
│ ┌────────────────┐                  │
│ │ Pin 1 ─────────┼─ 3.3V            │
│ │ Pin 2 ─────────┼─ D4              │
│ │ Pin 4 ─────────┼─ GND             │
│ └────────────────┘                  │
│                                     │
│ Rain Sensor                         │
│ ┌────────────────┐                  │
│ │ VCC ───────────┼─ 3.3V            │
│ │ GND ───────────┼─ GND             │
│ │ AO ────────────┼─ A0 (Conflict!)  │
│ └────────────────┘                  │
│                                     │
│ LDR Circuit                         │
│ ┌─────────────────┐                 │
│ │ 3.3V ───────────┼─ 3.3V           │
│ │     ┌───┐       │                 │
│ │     │LDR│       │                 │
│ │     └───┘       │                 │
│ │       │         │                 │
│ │     ┌────┐      │                 │
│ │     │10kΩ│      │                 │
│ │     └────┘      │                 │
│ │       │         │                 │
│ │       └─────────┼─ D3             │
│ │                 │                 │
│ │ GND ────────────┼─ GND            │
│ └─────────────────┘                 │
│                                     │
│ LED Circuit                         │
│ ┌─────────────────┐                 │
│ │ 3.3V ───────────┼─ 3.3V           │
│ │     ┌────┐      │                 │
│ │     │220Ω│      │                 │
│ │     └────┘      │                 │
│ │       │         │                 │
│ │     ┌────┐      │                 │
│ │     │LED │      │                 │
│ │     └────┘      │                 │
│ │       │         │                 │
│ │       └─────────┼─ D5             │
│ │                 │                 │
│ │ GND ────────────┼─ GND            │
│ └─────────────────┘                 │
└─────────────────────────────────────┘
```

## Important Wiring Note

**Pin Conflict Resolution:**
The rain sensor and battery monitoring both need analog input (A0). Solutions:

### Option 1: Priority to Battery Monitoring
```
Rain Sensor: Use digital output instead of analog
- Connect rain sensor DO to D6 (if available)
- Use digital threshold detection
- A0 reserved for battery monitoring
```

### Option 2: Analog Multiplexing
```
Use CD4051 analog multiplexer
- Connect multiple analog inputs to A0
- Switch between battery and rain sensor
- More complex but preserves both analog inputs
```

### Option 3: Separate Battery Monitoring
```
Use dedicated battery monitoring IC
- MAX17043 or similar fuel gauge
- I2C communication instead of analog
- Frees up A0 for rain sensor
```

## Recommended Solution: Digital Rain Sensor

```
Rain Sensor Digital Configuration
┌─────────────────┐
│ Rain Sensor     │
│ Module          │
│                 │
│ VCC ────────────┼─ 3.3V
│ GND ────────────┼─ GND
│ DO ─────────────┼─ D6 (GPIO12)
│ AO ─────────────┼─ (Not used)
└─────────────────┘
```

## Power Management Features

### Battery Protection
- Overcharge protection (4.2V cutoff)
- Over-discharge protection (2.5V cutoff)
- Short circuit protection
- Temperature protection

### Solar Charging
- Maximum power point tracking (MPPT) optional
- Reverse polarity protection
- Charging status indicators

### Power Optimization
- Deep sleep capability
- Battery level monitoring
- Low power warnings
- Automatic shutdown on critical battery level

## Assembly Instructions

### Step 1: Battery System
1. Install 18650 in holder with protection circuit
2. Connect to TP4056 charging module
3. Test charging with USB power
4. Verify protection circuit operation

### Step 2: Solar Integration
1. Connect solar panel to TP4056 input
2. Install Schottky diode for reverse protection
3. Test solar charging in direct sunlight
4. Verify charging LED indicators

### Step 3: Power Regulation
1. Connect battery output to 3.3V buck converter
2. Adjust output to 3.3V
3. Test with full load (all sensors active)
4. Verify efficiency (>90%)

### Step 4: Battery Monitoring
1. Build voltage divider (100kΩ + 100kΩ)
2. Connect to A0 pin
3. Calibrate with known voltage
4. Test accuracy

### Step 5: Weather Station Assembly
1. Connect all sensors to Wemos D1 Mini
2. Use digital rain sensor (D6) to free A0
3. Connect power from buck converter
4. Test complete system

## Expected Performance

### Solar Charging (6V 2W Panel)
- **Peak Current**: ~333mA @ 6V
- **Daily Energy**: ~2Wh (sunny day)
- **Charging Time**: 4-6 hours (full charge)

### Battery Runtime
- **Active Mode**: ~15 hours (2500mAh ÷ 160mA)
- **Deep Sleep**: ~125,000 hours (theoretical)
- **Mixed Operation**: Several days with solar support

### System autonomy
- **Sunny Location**: 100% solar powered
- **Cloudy Location**: Battery supplementation needed
- **Night Operation**: Battery powered only

## Troubleshooting

### Common Issues
- **No Charging**: Check solar panel orientation and connections
- **Low Battery**: Insufficient solar panel size
- **Inaccurate Reading**: Calibrate voltage divider
- **System Resets**: Check power supply stability

### Testing Procedures
1. **Solar Output**: Measure voltage and current in sunlight
2. **Charging Current**: Monitor battery charging rate
3. **System Load**: Measure total current consumption
4. **Battery Life**: Test runtime without solar input

This solar-powered system enables truly autonomous weather station operation with minimal maintenance requirements.