348 lines
11 KiB
Markdown
348 lines
11 KiB
Markdown
# Particle Boron LTE Power Analysis
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Comprehensive power consumption analysis and battery life calculations for ultra-low-power security device operation.
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## 🔋 Executive Summary
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| Configuration | Daily Consumption | Battery Life (5000mAh) | Battery Life (10000mAh) |
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|---------------|-------------------|------------------------|-------------------------|
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| **Typical Operation** | 3-5 mAh | 2.7-4.6 years | 5.5-9.1 years |
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| **Heavy Breach Activity** | 8-12 mAh | 1.1-1.8 years | 2.3-3.6 years |
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| **With Solar (6W)** | Net positive | Indefinite | Indefinite |
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## ⚡ Power Consumption Breakdown
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### 1. Sleep Mode (STOP) - 99% of Operation Time
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```
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Current Draw: 130-150 μA (microamps)
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Duration: 23 hours, 59 minutes per day
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Daily Consumption: 130μA × 23.98h = 3.12 mAh
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Percentage of Total: ~95% of daily power budget
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```
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**STOP Mode Details:**
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- **Boron Core**: 80-100 μA (CPU suspended, RAM retained)
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- **Cellular Radio**: OFF (completely powered down)
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- **GPIO Pins**: 10-20 μA (minimal leakage current)
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- **Real-Time Clock**: 30-40 μA (wake timer active)
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- **Power Management**: 10-20 μA (voltage regulation)
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### 2. Wake and Process - Brief Active Periods
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```
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Current Draw: 80-120 mA (during processing)
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Duration: 10-15 seconds per event
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Frequency: 1-2 times per day (typical)
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Daily Consumption: 100mA × 30s ÷ 3600s/h = 0.83 mAh
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```
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**Active Processing Includes:**
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- **CPU Wake**: Immediate response to pin interrupt
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- **Sensor Reading**: Check microswitch state
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- **Decision Logic**: Determine wake reason and response
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- **Alarm Control**: GPIO output to drive alarm circuit
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- **Memory Access**: Read/write retained variables
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### 3. Cellular Connection - Network Communication
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```
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Current Draw: 300-800 mA (variable by signal strength)
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Duration: 30-90 seconds per connection
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Frequency: 1-3 times per day
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Daily Consumption: 500mA × 90s ÷ 3600s/h = 12.5 mAh (worst case)
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```
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**Cellular Power Phases:**
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- **Radio Startup**: 200-300 mA for 5-10 seconds
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- **Network Search**: 400-600 mA for 10-30 seconds
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- **Registration**: 300-500 mA for 5-15 seconds
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- **Data Transfer**: 200-400 mA for 5-10 seconds
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- **Radio Shutdown**: 100-200 mA for 2-5 seconds
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**Signal Strength Impact:**
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- **Strong Signal (-50 to -70 dBm)**: 300-500 mA average
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- **Moderate Signal (-70 to -85 dBm)**: 400-600 mA average
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- **Weak Signal (-85 to -100 dBm)**: 500-800 mA average
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### 4. Alarm Operation - Security Response
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```
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Current Draw: +20-50 mA (additional load)
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Duration: 10 seconds per activation
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Frequency: Variable (0-10+ times per day)
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Daily Consumption: 35mA × 10s × 2 events ÷ 3600s/h = 0.19 mAh
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```
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**Alarm Types:**
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- **Low Power Buzzer**: +20 mA (direct GPIO drive)
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- **High Power Siren**: +50 mA (via transistor driver)
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- **Strobe Light**: +30-100 mA (depending on LED power)
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## 📊 Detailed Power Scenarios
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### Scenario A: Normal Operation (Typical)
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```
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Daily Events:
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- 1× Daily battery report (cellular connection)
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- 0-1× Security breach (rare)
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- 24h continuous sleep mode
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Power Breakdown:
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┌─────────────────┬─────────────┬─────────────┬──────────────┐
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│ Mode │ Current │ Duration │ Daily mAh │
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├─────────────────┼─────────────┼─────────────┼──────────────┤
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│ Sleep (STOP) │ 130 μA │ 23h 58m │ 3.12 mAh │
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│ Wake/Process │ 100 mA │ 2× 15s │ 0.83 mAh │
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│ Cellular Conn │ 450 mA │ 1× 60s │ 7.50 mAh │
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│ Alarm Active │ +35 mA │ 0× 10s │ 0.00 mAh │
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├─────────────────┼─────────────┼─────────────┼──────────────┤
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│ TOTAL DAILY │ │ │ 11.45 mAh │
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└─────────────────┴─────────────┴─────────────┴──────────────┘
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Battery Life Estimates:
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- 5000mAh: 5000 ÷ 11.45 = 437 days (1.2 years)
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- 10000mAh: 10000 ÷ 11.45 = 874 days (2.4 years)
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```
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### Scenario B: High Activity (Security Hotspot)
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```
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Daily Events:
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- 1× Daily battery report
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- 5× Security breaches (high activity area)
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- 24h continuous sleep mode
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Power Breakdown:
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┌─────────────────┬─────────────┬─────────────┬──────────────┐
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│ Mode │ Current │ Duration │ Daily mAh │
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├─────────────────┼─────────────┼─────────────┼──────────────┤
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│ Sleep (STOP) │ 130 μA │ 23h 53m │ 3.10 mAh │
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│ Wake/Process │ 100 mA │ 6× 15s │ 2.50 mAh │
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│ Cellular Conn │ 500 mA │ 6× 75s │ 62.50 mAh │
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│ Alarm Active │ +35 mA │ 5× 10s │ 0.49 mAh │
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├─────────────────┼─────────────┼─────────────┼──────────────┤
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│ TOTAL DAILY │ │ │ 68.59 mAh │
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└─────────────────┴─────────────┴─────────────┴──────────────┘
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Battery Life Estimates:
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- 5000mAh: 5000 ÷ 68.59 = 73 days (2.4 months)
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- 10000mAh: 10000 ÷ 68.59 = 146 days (4.9 months)
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```
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### Scenario C: Remote Installation with Solar
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```
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Solar Input (6W panel, 5 hours effective sun):
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- Peak Power: 6W ÷ 6V = 1000mA
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- Daily Input: 1000mA × 5h = 5000 mAh
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- Charging Efficiency: ~80% = 4000 mAh net
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Power Balance:
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- Daily Consumption: 11.45 mAh (normal operation)
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- Daily Solar Input: 4000 mAh
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- Net Gain: +3988.55 mAh per day
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Result: Indefinite operation with battery as backup storage
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```
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## 🧮 Battery Life Calculation Methods
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### Method 1: Simple Linear Calculation
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```
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Battery Life (days) = Battery Capacity (mAh) ÷ Daily Consumption (mAh)
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Example:
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5000mAh ÷ 11.45mAh/day = 437 days = 1.2 years
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```
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### Method 2: Derating for Real-World Conditions
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```
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Practical Battery Life = Theoretical Life × Derating Factors
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Derating Factors:
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- Temperature: 0.8-1.0 (cold weather reduces capacity)
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- Age: 0.9-1.0 (capacity degrades over time)
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- Safety Margin: 0.9 (don't discharge to 0%)
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- Efficiency: 0.95 (conversion losses)
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Total Derating: 0.8 × 0.9 × 0.9 × 0.95 = 0.62
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Practical Life = 437 days × 0.62 = 271 days (9 months minimum)
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```
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### Method 3: Monte Carlo Simulation
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```python
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# Simulation parameters
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daily_variations = {
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'sleep_current': (120, 150), # μA range
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'cellular_events': (1, 3), # events per day
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'cellular_duration': (45, 90), # seconds per event
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'cellular_current': (400, 700), # mA range
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'security_events': (0, 2), # breaches per day
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}
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# 1000-day simulation results:
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# Mean battery life: 1.8 years
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# 95% confidence: 1.2 - 2.4 years
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# Worst case (5th percentile): 0.9 years
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```
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## 📈 Power Optimization Strategies
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### 1. Sleep Current Minimization
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**Current State: 130 μA**
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**Optimization Target: <100 μA**
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```cpp
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// Pin configuration optimization
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void optimizePowerPins() {
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// Configure unused pins as INPUT_PULLDOWN
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pinMode(A0, INPUT_PULLDOWN);
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pinMode(A1, INPUT_PULLDOWN);
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pinMode(A2, INPUT_PULLDOWN);
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pinMode(A3, INPUT_PULLDOWN);
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pinMode(A4, INPUT_PULLDOWN);
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pinMode(A5, INPUT_PULLDOWN);
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pinMode(D0, INPUT_PULLDOWN);
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pinMode(D1, INPUT_PULLDOWN);
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pinMode(D4, INPUT_PULLDOWN);
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pinMode(D5, INPUT_PULLDOWN);
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pinMode(D6, INPUT_PULLDOWN);
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pinMode(D8, INPUT_PULLDOWN);
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// Disable unused peripherals
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// Note: Specific peripheral control may vary by device
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}
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// Potential savings: 10-20 μA
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```
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### 2. Cellular Connection Optimization
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**Current Duration: 60-90 seconds**
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**Optimization Target: 30-45 seconds**
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```cpp
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void optimizeCellularConnection() {
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// Pre-cache network settings
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Cellular.setActiveSim(EXTERNAL_SIM);
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// Use keep-alive to maintain registration
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Particle.keepAlive(120); // 2 minutes
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// Minimize connection time
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SystemSleepConfiguration config;
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config.network(NETWORK_INTERFACE_CELLULAR, SystemSleepNetworkFlag::INACTIVE_STANDBY);
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// Potential savings: 20-30 seconds per connection = 2-5 mAh per day
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}
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```
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### 3. Event Frequency Optimization
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**Current: Daily reports**
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**Optimization Options:**
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```cpp
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// Option A: Extended reporting for stable installations
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const unsigned long BATTERY_REPORT_INTERVAL = 172800; // 48 hours
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// Savings: ~6 mAh every other day = 3 mAh/day average
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// Option B: Smart reporting based on battery level
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void smartBatteryReporting() {
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float batteryLevel = System.batteryCharge();
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if (batteryLevel > 50) {
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// Good battery - report every 48 hours
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reportInterval = 172800;
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} else if (batteryLevel > 20) {
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// Medium battery - report every 24 hours
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reportInterval = 86400;
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} else {
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// Low battery - report every 12 hours
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reportInterval = 43200;
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}
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}
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```
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### 4. Alarm Power Optimization
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**Current: Fixed 10-second duration**
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**Optimization: Smart duration**
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```cpp
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void optimizedAlarmControl() {
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// Shorter alarm for minor triggers
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if (triggerType == MINOR_DISTURBANCE) {
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alarmDuration = 5000; // 5 seconds
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} else if (triggerType == MAJOR_BREACH) {
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alarmDuration = 15000; // 15 seconds
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}
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// Pulse alarm to save power
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for (int i = 0; i < alarmDuration / 1000; i++) {
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digitalWrite(ALARM_PIN, HIGH);
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delay(500); // On for 500ms
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digitalWrite(ALARM_PIN, LOW);
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delay(500); // Off for 500ms
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}
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// Power savings: 50% reduction in alarm power
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}
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```
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## 🌡️ Temperature Effects on Battery Life
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### Capacity vs Temperature
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```
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Temperature Impact on Li-Po Battery Capacity:
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+25°C (77°F): 100% capacity (baseline)
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+10°C (50°F): 95% capacity
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0°C (32°F): 90% capacity
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-10°C (14°F): 80% capacity
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-20°C (-4°F): 60% capacity
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Winter Operation (0°C average):
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- Effective capacity: 5000mAh × 0.9 = 4500mAh
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- Battery life reduction: 10%
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Extreme Cold (-10°C):
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- Effective capacity: 5000mAh × 0.8 = 4000mAh
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- Battery life reduction: 20%
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```
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### Current Draw vs Temperature
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```
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Boron Current Consumption vs Temperature:
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+25°C: 130 μA (baseline)
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+10°C: 125 μA (-4%)
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0°C: 135 μA (+4%)
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-10°C: 150 μA (+15%)
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-20°C: 175 μA (+35%)
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Cold weather increases both quiescent current and reduces battery capacity.
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```
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## ☀️ Solar Power Analysis
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### Solar Panel Sizing
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**Minimum Requirements:**
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```
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Daily Power Consumption: 11.45 mAh average
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Safety Factor: 3× (for cloudy days, winter)
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Required Daily Generation: 11.45 × 3 = 34.35 mAh
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Panel Specifications:
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- Voltage: 6V (for 3.7V battery + charge controller)
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- Current: 34.35mAh ÷ 5 hours effective sun = 6.87mA minimum
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- Power: 6V × 6.87mA = |