📬 Smart Post Box

© by Thevapriyan

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📖 Project Overview

The Smart Post Box is an IoT-based system that uses a NodeMCU ESP8266 and Arduino Mega to detect letters or parcels placed inside the post box. It utilizes an Ultrasonic Sensor to measure the distance, and when an object is detected (mail inserted), the system updates the status on the Blynk App.

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⚙️ Hardware Components

Component	Description
NodeMCU ESP8266	WiFi Module & Main Controller
Arduino Mega	Connected to NodeMCU for power
Ultrasonic Sensor	Measures distance (Detects mail)
LED	Status indicator (optional)

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📡 Wiring Diagram

NodeMCU Pin	Connected To
Vin	Mega 5V
Gnd	Mega Gnd
D3	Ultrasonic Echo Pin
D4	Ultrasonic Trig Pin
D5	Optional LED (Indicator)

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📱 Blynk App Setup

1. Download and install the Blynk App.
2. Create a new project and select ESP8266 as the device.
3. Add a Display Widget on virtual pin V1 to show the mail count.
4. Get the Auth Token from Project Settings (nut icon).

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🔗 WiFi and Blynk Configuration

Replace these placeholders in the code with your actual credentials:

char auth[] = "Your_Blynk_Auth_Token";  // From Blynk App
char ssid[] = "Your_WiFi_SSID";          // Your WiFi network name
char pass[] = "Your_WiFi_Password";      // Your WiFi password