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Nexus-Guard-Suite/reference/esp32-agent/docs/HARDWARE.md
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datadunia 84689b208e docs: add ESP32 and iOS agent architecture reference 
- reference/esp32-agent/: DESIGN, HARDWARE, API_COMPAT, ARCHITECTURE, README

- reference/ios-agent/: DESIGN, API_COMPAT, UI_DESIGN, ARCHITECTURE, README

- Both mirror Android agent architecture, UI design, and heartbeat flow

- Architecture-only (no code) — avoids submodule conflicts

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
2026-07-06 14:20:10 +07:00

9.2 KiB
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Hardware Reference

Version: 1.0.0 Date: 2026-06-26

1. Target Hardware

1.1 LW840X Module

The LW840X is an ESP32-based WiFi module designed for IoT applications.

Specification Value
MCU ESP32 (Xtensa LX7 dual-core)
Clock 240 MHz
RAM 520 KB SRAM
Flash 4 MB (external)
WiFi 802.11 b/g/n (2.4 GHz)
Bluetooth None (LW840X)
GPIO 20+ (depends on module)
ADC 18 channels (12-bit)
Operating Temp -40°C to +85°C
Voltage 3.0V to 3.6V

1.2 Pin Mapping

LW840X Module Pinout
┌─────────────────────────────────────┐
│                                     │
│  3V3  ─┐                           │
│  GND  ─┤                           │
│  EN   ─┤                           │
│  IO0  ─┤  Boot/Flash mode          │
│  IO1  ─┤  TX0 (UART0)             │
│  IO3  ─┤  RX0 (UART0)             │
│  IO4  ─┤  Status LED               │
│  IO5  ─┤  (reserved)               │
│  IO12 ─┤  (reserved)               │
│  IO13 ─┤  (reserved)               │
│  IO14 ─┤  (reserved)               │
│  IO15 ─┤  (reserved)               │
│  IO16 ─┤  (reserved)               │
│  IO17 ─┤  (reserved)               │
│  IO18 ─┤  (reserved)               │
│  IO19 ─┤  (reserved)               │
│  IO21 ─┤  (reserved)               │
│  IO22 ─┤  (reserved)               │
│  IO23 ─┤  (reserved)               │
│  IO25 ─┤  (reserved)               │
│  IO26 ─┤  (reserved)               │
│  IO27 ─┤  (reserved)               │
│  IO32 ─┤  (reserved)               │
│  IO33 ─┤  (reserved)               │
│  IO34 ─┤  (reserved)               │
│  IO35 ─┤  (reserved)               │
│                                     │
└─────────────────────────────────────┘

1.3 Minimal Circuit

Power Supply:
  3.3V ──── LW840X 3V3
  GND  ──── LW840X GND

Decoupling:
  100nF ceramic capacitor between 3V3 and GND (close to module)

Boot/Flash:
  IO0 ──── 10K pull-up to 3V3 (normal boot)
  IO0 ──── GND (flash mode)

Status LED:
  IO4 ──── 220Ω ──── LED ──── GND

UART (for debugging):
  IO1 (TX0) ──── USB-UART RX
  IO3 (RX0) ──── USB-UART TX
  GND        ──── USB-UART GND

2. Power Requirements

2.1 Current Consumption

Mode Current Notes
Active (WiFi TX) 130-170 mA Transmitting data
Active (WiFi RX) 80-100 mA Receiving data
Modem Sleep 15-20 mA WiFi connected, low duty cycle
Light Sleep 0.8-1.5 mA CPU paused, WiFi wake
Deep Sleep 5-10 µA RTC only, wake on GPIO
Off 0 µA No power

2.2 Power Supply Design

Recommended:
  Input: 5V USB or 12V DC
  Regulator: AMS1117-3.3 or similar LDO
  Capacity: 500mA minimum
  
  ┌─────────┐     ┌─────────┐     ┌─────────┐
  │ 5V USB  │────▶│  LDO    │────▶│ LW840X  │
  │         │     │ 3.3V    │     │         │
  └─────────┘     └─────────┘     └─────────┘
                      │
                     GND

2.3 Battery Operation

For battery-powered applications:

Battery Capacity Runtime (Active) Runtime (Sleep)
CR2032 225 mAh ~1.5 hours ~2 years
18650 3400 mAh ~20 hours ~30 years
LiPo 1000mAh 1000 mAh ~6 hours ~10 years

Note: Deep sleep with periodic wake (e.g., every 5 minutes) is recommended for battery operation.

3. Antenna Options

3.1 PCB Trace Antenna

  • Pros: Low cost, compact
  • Cons: Lower gain, sensitive to placement
  • Range: 10-30m (indoor)
  • Use Case: Short-range, cost-sensitive

3.2 U.FL Connector

  • Pros: Higher gain, flexible placement
  • Cons: Additional cost, larger size
  • Range: 50-100m (indoor)
  • Use Case: Longer range, industrial

3.3 External Antenna

  • Pros: Best performance, directional options
  • Cons: Highest cost, largest size
  • Range: 100m+ (outdoor)
  • Use Case: Outdoor, long-range

4. Development Board

4.1 ESP32-DevKitC

Recommended for development and prototyping.

Feature Specification
MCU ESP32-WROOM-32
Flash 4 MB
RAM 520 KB SRAM
WiFi 802.11 b/g/n
Bluetooth BT 4.2 + BLE
USB Micro-USB (CP2102)
GPIO 38 pins
Price ~$5-10

4.2 Flashing

# Install ESP-IDF
# https://docs.espressif.com/projects/esp-idf/en/latest/esp32/get-started/

# Set target
idf.py set-target esp32

# Build
idf.py build

# Flash (auto-detect port)
idf.py -p /dev/ttyUSB0 flash

# Monitor
idf.py -p /dev/ttyUSB0 monitor

4.3 Pin Connections (DevKit)

Status LED:
  GPIO4 ──── 220Ω ──── LED ──── GND

Debug UART (optional):
  GPIO1 (TX0) ──── USB-UART RX
  GPIO3 (RX0) ──── USB-UART TX
  GND          ──── USB-UART GND

5. Production Board

5.1 Design Guidelines

  1. Power:

    • Use 3.3V LDO with 500mA capacity
    • Add 100nF ceramic capacitor close to 3V3 pin
    • Add 10µF tantalum capacitor for bulk decoupling

  2. Antenna:

    • Keep antenna area clear of copper pours
    • Minimum 10mm clearance around antenna
    • Use U.FL connector for external antenna

  3. Layout:

    • Route UART traces away from antenna
    • Keep crystal traces short
    • Ground plane under module

  4. Enclosure:

    • Use non-metallic enclosure (plastic)
    • Ensure antenna is not shielded
    • Provide mounting holes

5.2 Bill of Materials (BOM)

Component Quantity Package Notes
LW840X 1 Module ESP32-based
AMS1117-3.3 1 SOT-223 3.3V LDO
100nF 2 0402 Decoupling
10µF 1 0805 Bulk cap
220Ω 1 0402 LED resistor
LED 1 0603 Status indicator
U.FL 1 SMD Antenna connector
Header 1 2.54mm Debug UART

5.3 Schematic

                    ┌─────────────────┐
                    │    LW840X       │
  3.3V ────────────┤ 3V3         GND ├──── GND
                    │                 │
  IO4 ──── 220Ω ───┤ IO4         TX0 ├──── UART RX
         └── LED ──┤             RX0 ├──── UART TX
              GND  │                 │
                   │             EN  ├──── 10K ──── 3.3V
                   │                 │
                   │             IO0 ├──── 10K ──── 3.3V
                   │                 │           (flash: GND)
                   └─────────────────┘

6. Testing & Validation

6.1 Hardware Tests

  1. Power-on Test:

    • Verify 3.3V at module pin
    • Check current consumption (~50mA idle)
    • Confirm LED blinks on boot

  2. WiFi Test:

    • Scan for WiFi networks
    • Connect to test AP
    • Measure RSSI at distance

  3. UART Test:

    • Send AT commands (if firmware supports)
    • Verify debug output
    • Check baud rate (115200)

  4. Flash Test:

    • Write/read NVS data
    • Verify flash size
    • Test wear leveling

6.2 Production Test

  1. Functional Test:

    • Provision with test server
    • Verify WireGuard handshake
    • Check heartbeat response

  2. Stress Test:

    • Run for 24+ hours
    • Monitor memory leaks
    • Verify reconnection after WiFi drop

  3. Environmental Test:

    • Operating temperature range
    • Humidity resistance
    • Vibration resistance

7. Troubleshooting

7.1 Common Issues

Symptom Cause Solution
No boot IO0 held low Remove flash jumper
No WiFi Antenna issue Check antenna connection
High current WiFi always on Use modem sleep
Crash on boot Stack overflow Increase task stack size
Provision fail Token expired Get new token from server

7.2 Debug Tools

  • Serial Monitor: idf.py monitor
  • JTAG Debugger: OpenOCD + GDB
  • Logic Analyzer: Saleae or similar
  • Power Analyzer: Monsoon or similar

8. Compliance

8.1 Certifications

  • FCC: Required for US market
  • CE: Required for EU market
  • IC: Required for Canada market
  • TELEC: Required for Japan market

8.2 Testing

  • EMC testing (emissions and immunity)
  • SAR testing (if applicable)
  • Environmental testing (temperature, humidity)

9. References

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