Project Overview

This is a no-code smart home automation system built around the NodeMCU ESP8266 and a 4‑channel 5 V relay module, configured through the Cadio mobile app—no firmware coding required .
It lets you control up to four appliances via Cadio’s app, voice assistants like Google Assistant and Amazon Alexa, as well as manual push-button switches when offline .

Key Features include:

• Voice control through Google Assistant and Amazon Alexa

• Cadio app dashboard control and real-time feedback

• Local manual control via push buttons if Wi-Fi is unavailable

• Automatic device scheduling (timers)

• EEPROM memory of device states after power outages

• Over-the-air (OTA) Wi‑Fi reconfiguration via physical button

• Entire setup requires no programming, just GUI configuration 

 Hardware Components

• NodeMCU ESP8266 board

• 4‑channel 5 V SPDT relay module

• Pushbuttons or switches (up to 4) for manual override

• Power source: typical 5 V USB adapter (e.g. mobile charger)

• (Optional) Custom PCB with transistors (BC547), optocouplers (PC817), LEDs, resistors, diodes for robust switching and safety \

GPIO pin usage (basic setup):

• D1 (GPIO5), D2 (GPIO4), D5 (GPIO14), D6 (GPIO12) → relay inputs

• SD3 (GPIO10), D3 (GPIO0), D7 (GPIO13), RX (GPIO3) → pushbuttons (use INPUT_PULLUP mode)

 Firmware & Configuration

This project uses Cadio's dynamic firmware, not traditional code. Steps:

1. Flash the firmware to NodeMCU using an ESP flashing tool:

   • Firmware file installed at address 0x0, SPI mode DIO, SPI speed 40 MHz

   • Activate DoNotChgBin option, erase flash before uploading 

2. Reset the ESP8266; wait ~30 seconds until onboard LED blinks—ESP is ready for configuration .

3. Configure via Cadio app:

   • Connect to the ESP8266's “CADIO” hotspot

   • Set switch & relay modes (e.g. “PRESS” vs “NORMAL”, active‑LOW or HIGH)

   • Assign GPIO pins, export configuration, input Wi‑Fi credentials and unique device name

   • Save and launch dashboard 

 Operation Modes

• App Control: Use Cadio app interface to toggle appliances and schedule operations.

• Voice Control: Link Cadio account with Google Home and Alexa to control devices using voice commands—no code required

• Local Switch Control: If Wi‑Fi is down, manual buttons still work to control relays directly

• State Persistence: Devices remember last on/off state after reboot/power loss, thanks to EEPROM support 

• Wi‑Fi Reconfiguration via OTA: Hold a specific pushbutton for ~4 seconds to reboot into config hotspot for updating Wi‑Fi settings via the Cadio app

 Summary Table

 Why Use This System?

• You don’t need to program—ideal for beginners and rapid DIY deployment

• Compatible with voice platforms (Google Assistant, Alexa) with minimal setup

• Reliable fallback with physical switch control if Wi‑Fi is unavailable

• State persistence and scheduling make it practical for daily use

• Over-the-air updates let you change Wi‑Fi settings easily without rewiring