Tech Arcanist

Multisense Intellinest

The MultiSense IntelliNest is an advanced smart home automation system built using an ESP32 and a 16-channel relay module. It allows control of electrical appliances in multiple ways — Manual Control, Touch Control, Motion-Based Automation, Voice Automation, and Internet Control (Blynk IoT). The system is designed for maximum flexibility and reliability: || Manual Control || Touch Buttons || Auto Motion Control || Internet/App Control || Voice Automated ||

Features

  • 16-Channel Relay Control
    • Each relay is connected to a 3-pin AC plug point for direct appliance control.
  • Four Control Methods
    • Manual Control using push buttons
    • Touch Control using capacitive touch pads
    • Auto Mode using PIR motion sensor
    • Remote IoT Control using Blynk App (Internet-based)
  • Voice Control Automation
    • Commands like: “Turn on fan plug 3” or “Switch off plug 7”
  • Blynk IoT Integration
    • Control all 16 appliances from anywhere using smartphone
    • Real-time status monitoring in app
  • GPIO Expansion with Multiplexers
    • Used PCF8575 + PCF8574 expanders to handle high I/O count
    • Enables ESP32 to manage multiple inputs for touch, push buttons, and relays
  • Failsafe Manual Override
    • Even if WiFi or the app fails, touch buttons & manual switches continue working

Components Used

  • ESP32 — Main controller with Wi-Fi for Blynk IoT
  • 16-Channel Relay Board — Controls AC appliances
  • PCF8575 + PCF8574 I/O Expanders — Increase GPIO count
  • Blynk IoT App — Smartphone control via cloud
  • Voice Assistant Integration (third-party app)
  • PIR Motion Sensor — Auto light/appliance activation
  • TTP229 16-Way Capacitive Touch Switch Digital keypad Module — Touch-based on/off control
  • Mechanical Push Buttons — Manual control / failsafe override
  • 3-Pin Plug Sockets (16 pcs) — Individual relay output connections
  • Power Supply — To power ESP32 & relay module

How it Works

  • Inputs from touch buttons, push buttons, and PIR sensor are read via I/O expanders.
  • ESP32 receives commands from Blynk app over Wi-Fi.
  • ESP32 triggers the appropriate relay on the 16-channel board.
  • Each relay switches an AC plug point → appliance ON/OFF.
  • Voice commands are sent locally to ESP32 using its IP address.
  • All three control systems (manual + touch + Blynk IoT) work simultaneously.

Media Availability (Important Note)

This project was built a long time ago.
There are very limited photos/videos of the working system

Achievement

This project was showcased in a college project competition, along with other projects.
Won 2nd place and received ₹25,000 cash prize.

Showcasing Our Project

Certificate

Working

Voice Automation (Insta Highlight)

Old Working Progress Snaps

Old Working Progress Snaps

Circuit

Circuit Diagram

My Learnings

  • How to expand GPIO pins using PCF8575 and PCF8574 I/O expanders to control multiple relays and input modules
  • Designing a hybrid control architecture where:
  • Manual switches,
    • Touch buttons,
    • PIR motion sensor,
    • IoT app (Blynk),
    • Voice commands (via local IP) all work together without interfering with each other
  • Implementing voice automation using local IP HTTP commands, allowing ESP32 to control devices without cloud or internet dependency
  • Using Blynk IoT for internet-based appliance control and monitoring
  • Working with high-voltage relay modules safely, ensuring isolation from low-voltage ESP32 logic
  • Managing simultaneous control inputs without relay flickering or code blocking
  • Using the Ticker library to create time-based non-blocking tasks (automation timers, auto-off timers, polling touch inputs without delay())
  • Structuring firmware to make ESP32 responsive even when multiple events occur simultaneously