🔌 Arduino Uno + Wemos D1 Wiring Guide

Complete connection diagram for your 3-sensor monitoring system

🔵 Arduino Uno

Your current setup with sensors

📍 Current Sensor Connections:

  • D2 Flame Sensor (DO_PIN)
  • A3 Vibration Sensor
  • A0 Water Sensor (Analog)
  • D13 LED Green (Vibration)
  • D12 LED Red (Heat)
  • D9 LED Blue (Water)
  • D10 MP3 Player RX
  • D11 MP3 Player TX

🔗 Wemos D1 Connection:

  • TX (D1) Serial Transmit → Wemos RX
  • GND Ground → Wemos GND

🔴 Wemos D1 (ESP8266)

WiFi module for Flutter app

🔗 Arduino Connection:

  • RX (D8) Serial Receive ← Arduino TX
  • GND Ground ← Arduino GND

⚡ Power Supply:

  • 5V Power from USB or separate supply

📡 WiFi:

  • Built-in Connects to your WiFi network

📊 Wiring Connection Table

Arduino Uno Pin Wemos D1 Pin Connection Type Purpose
TX (D1) RX (D8) SERIAL DATA Send sensor data from Arduino to Wemos
GND GND GROUND Common ground reference

🎨 Visual Connection Diagram

🔵
Arduino Uno
TX (Pin D1)
GND
TX
RX
GND
GND
🔴
Wemos D1
RX (Pin D8)
GND

⚠️ Important Notes

  • Serial Communication: Arduino TX connects to Wemos RX. Data flows ONE WAY (Arduino → Wemos)
  • Ground Connection: MUST connect GND to GND for proper communication
  • Power Supply: Power Arduino Uno and Wemos D1 separately (both via USB or external power)
  • Baud Rate: Both devices use 9600 baud rate (already set in your code)
  • Data Format: Arduino sends: "HD:0,VD:1,WD:0,WL:450" every 500ms
  • No RX Connection Needed: Since Arduino only SENDS data, you don't need to connect Arduino RX to Wemos TX
  • WiFi Setup: Update WiFi credentials in Wemos D1 code before uploading
  • Testing: Open Serial Monitor on both Arduino IDE ports to verify data transmission