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ESP32 Setup Guide

Complete guide to setting up ESP32 sensor nodes.

Hardware Requirements

  • ESP32 development board
  • USB cable (for programming)
  • DHT11 or DHT22 sensor (optional - code uses random data)
  • 2x LEDs (green and red)
  • 2x 220Ω resistors
  • Breadboard and jumper wires

Pin Connections

  • GPIO 5: Green LED (+ resistor) → Data publishing indicator
  • GPIO 4: Red LED (+ resistor) → Error indicator
  • GND: Common ground for LEDs

Software Setup

1. Install MicroPython

Download firmware: 

wget https://micropython.org/resources/firmware/ESP32_GENERIC-20240222-v1.22.2.bin

Flash to ESP32: 

esptool.py --port /dev/ttyUSB0 erase_flash
esptool.py --port /dev/ttyUSB0 write_flash -z 0x1000 ESP32_GENERIC-20240222-v1.22.2.bin

2. Upload Sensor Code

Files to upload: - services/sensors/hardware/main.py - services/sensors/hardware/config.py

Using ampy: 

pip install adafruit-ampy
ampy --port /dev/ttyUSB0 put config.py
ampy --port /dev/ttyUSB0 put main.py

3. Configure WiFi

Edit config.py: 

WIFI_SSID = "YourWiFiNetwork"
WIFI_PASSWORD = "YourPassword"

4. Start Sensor

Reboot ESP32 or run: 

import main

LED Indicators

  • Green Blinking: Publishing sensor data
  • Red Flash: Error (network, gateway unreachable)
  • Both Off: Idle or not configured

Troubleshooting

Can't Connect to WiFi

  • Verify SSID and password in config.py
  • Check 2.4GHz network (ESP32 doesn't support 5GHz)
  • Ensure router allows new devices

Can't Find Gateway

  • Verify gateway is running
  • Check ESP32 on same network
  • Test mDNS: ping greencop-gateway.local

Red LED Always On

  • Gateway unreachable
  • Network error
  • Check serial output for details

Next Steps