https://github.com/ajeyverma/smartcontroller

An IoT-based smart system built with Arduino and MIT App Inventor that controls LEDs, fans, and alarms using sensors and Bluetooth connectivity.
https://github.com/ajeyverma/smartcontroller

3-channels-relay ajeyverma alarm-control arduino arduino-nano arduino-uno bluetooth convertor fan-controller ldr-sensor led-controller live-status mitapp mitappinventor mobile-app pir-sensor relay smartcontroller temperature-monitoring thermistor

Last synced: 26 days ago
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An IoT-based smart system built with Arduino and MIT App Inventor that controls LEDs, fans, and alarms using sensors and Bluetooth connectivity.

• Host: GitHub
• URL: https://github.com/ajeyverma/smartcontroller
• Owner: ajeyverma
• Created: 2025-04-29T19:30:31.000Z (about 1 year ago)
• Default Branch: main
• Last Pushed: 2025-08-29T20:00:23.000Z (10 months ago)
• Last Synced: 2025-11-07T13:02:55.780Z (7 months ago)
• Topics: 3-channels-relay, ajeyverma, alarm-control, arduino, arduino-nano, arduino-uno, bluetooth, convertor, fan-controller, ldr-sensor, led-controller, live-status, mitapp, mitappinventor, mobile-app, pir-sensor, relay, smartcontroller, temperature-monitoring, thermistor
• Language: C++
• Homepage:
• Size: 10.2 MB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: Docs/README.md

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README

          
# Smart Controller Overview

## Smart Bluetooth-Based Controller

**Introduction:**

A compact, smart system using Arduino Nano, controlled via Bluetooth using a custom MIT App Inventor interface.

**Key Features:**

- Dual mode: Automatic / Manual

- Real-time temperature monitoring

- Day-night detection via LDR

- Motion sensing with PIR sensor

- Control over LED, Fan, and Alarm using relays

- Live status indicators on mobile app

**Components Used:**

- Arduino Nano

- LDR, PIR, LM35 (Thermistor)

- Bluetooth Module (HC-05)

- Relay Module

- Solar panel with AC-DC converter backup

---

**App & Code Integration**

**App Functionality:**

- Bluetooth connection control

- Toggle between Auto and Manual modes

- Manual ON/OFF switches for LED, Fan, Alarm

- Live status LEDs for device states

- Real-time temperature display

**Arduino Code Logic Highlights:**

- Reads LDR, PIR, and temperature values

- Auto Mode:

  - LED ON when dark + motion

  - Fan ON when motion + temp > 27°C

  - Alarm ON when temp > 100°C

- Manual Mode:

  - App toggles each device

- Sends live status & temperature to app via Bluetooth

# ⚙️Setup

⚡ Power Supply Setup



  If using solar power, connect the solar panel to a charge controller and use a voltage regulator (e.g., AMS1117 or 7805) to provide a stable 5V output for the Arduino and components.





  For backup power, connect an AC-DC adapter (5V output) that automatically takes over when solar input is low or unavailable. Ensure proper power isolation if needed.



🧩 Wiring Notes

Ensure all components share a common ground with the Arduino. Here's how to wire each module:


🔆 LDR (Light Sensor)



  Use a voltage divider with a 10kΩ resistor. Connect:





  
5V → LDR → Junction

  
Junction → 10kΩ Resistor → GND

  
Junction → D2 (LDR_PIN)





  This setup lets D2 read LOW when dark and HIGH when bright.



🌡️ LM35 Temperature Sensor



  
LM35 VCC → 5V

  
LM35 GND → GND

  
LM35 OUT → A3 (THERMISTOR_PIN)





  LM35 outputs 10mV/°C. For example, 27°C = ~0.27V.



🚶 PIR Motion Sensor



  
PIR VCC → 5V

  
PIR GND → GND

  
PIR OUT → D4 (PIR_PIN)





  Use “H” jumper mode on the PIR for continuous signal while motion persists.



🔌 Relays (LED, Fan, Alarm)



  
Relay IN1 → D8 (LED_RELAY_PIN)

  
Relay IN2 → D9 (FAN_RELAY_PIN)

  
Relay IN3 → D10 (ALARM_RELAY_PIN)

  


Relay VCC → 5V, GND → GND







  Connect your high-voltage devices (e.g., bulb, fan, buzzer) to the NO (Normally Open) and COM terminals.



📶 HC-05 Bluetooth Module



  
HC-05 TX → D6 (Arduino RX via SoftwareSerial)

  
HC-05 RX → Voltage Divider → D7 (Arduino TX)

  


VCC → 5V, GND → GND





Voltage Divider for HC-05 RX (to drop 5V TX signal to ~3.3V):


Arduino TX --- 1kΩ ---+--- 2kΩ --- GND

                      |

                   HC-05 RX





  This prevents damage to the HC-05's 3.3V logic input pin.



## 🔌 Pin Connections

  

    

      Component

      Arduino Pin

      Notes

    

  

  

    

      LDR

      D2 (Digital)

      Use with voltage divider; LOW when dark

    

    

      LM35 Temperature Sensor

      A3 (Analog)

      Middle pin to A3; VCC & GND to 5V/GND

    

    

      PIR Motion Sensor

      D4 (Digital)

      OUT to D4; requires 5V and GND

    

    

      Relay (LED)

      D8

      IN pin of relay module

    

    

      Relay (Fan)

      D9

      IN pin of relay module

    

    

      Relay (Alarm)

      D10

      IN pin of relay module

    

    

      Bluetooth HC-05

      D6 (RX), D7 (TX)

      Use voltage divider on HC-05 RX

    

  

Note: Connect all VCCs to 5V and all GNDs to common ground.