Smart Curtain project: To control curtain in my dorm's walk in closet

##1. Project Overview SmartCurtain is a computer engineering project that designed to close a curtain automatically while displaying the status of the walk in closet(occupied or empty). I used a Arduino nano and a customized PCB for this project. This project is aimmed to move beyond a breadboard prototype and moved on to a professional, manufactured hardware solution that integrates motor control, user feedback via LCD and power management.

Key Features

• State-Based Control: Toggles between "VACANT" (Open) and "OCCUPIED" (Closed) modes.
• H-Bridge Integration: Utilizes PWM (Pulse Width Modulation) for smooth motor speed control.
• Visual Feedback: Dedicated 16x2 LCD displays current occupancy status.
• Single-Button Interface: Simplified user interaction using internal pull-up resistors for debounced input.

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##2. Hardware Design

Parameter	Detail
Microcontroller	Arduino Nano (ATmega328P)
Display	16x2 LCD (HD44780)
Motor Type	Greatisan DC 12V Gearbox
Logic Voltage	5V DC
Motor Voltage	[12V DC]
**Motor **	[Insert Voltage, e.g., 12V DC]

##Hardware mapping

Component	Arduino Pin	Function
LCD RS, EN, D4-D7	12, 11, 5, 4, 3, 2	Parallel Data Interface
Button	7	State Toggle (INPUT_PULLUP)
H-Bridge IN1	8	Motor Direction A
H-Bridge IN2	9	Motor Direction B
H-Bridge ENA	10	Motor Speed (PWM)

Engineering Decisions

• EMI Mitigation: A ground plane was implemented on the bottom layer to provide a stable return path and reduce electromagnetic interference from the motor.
• Trace Optimization: Power traces were widened to [Insert Width, e.g., 30mil] to accommodate motor current draw.
• DFM Compliance: Conducted a Design for Manufacturability (DFM) check to resolve silkscreen overlaps and ensure high solderability.

3. Repository Structure

• /Hardware: Gerber files, Schematic PDFs, and EasyEDA project source.

• /Firmware: Arduino (.ino) source code for motor logic and LCD interfacing.

• /Media: 3D renders, circuit diagrams, and photos of the final assembly.

• 4. Bill of Materials (BOM)

Ref	Component	Quantity	Purpose
U1	Arduino Nano	1	System Controller
M1	Motor Driver	1	[e.g., A4988] Motor Interface
LCD1	16x2 LCD	1	Status Display
RV1	10k Potentiometer	1	LCD Contrast Adjustment
C1	100uF Capacitor	1	Power Smoothing

##5. Experince gained

• ***PCB design workflow refined. I had the chance to go over the entire process of designing a PCB again(second time) and I am much more confident designing my own PCB now.
• ***Hardware Integration I have learned how to use a geared motor and a hbridge to allow curtain to open up and close.
• ***Mannaged International fabrication I ordered my own PCB from JLPCB and can manage the whole process by myself, I am confident enough to turn all of my future projects into PCB formats.

Development Journey: From Breadboard to PCB

1. Prototype Phase

Initial testing was conducted on a breadboard to verify the logic of the H-Bridge motor driver and the LCD state machine.

2. Custom PCB Design

Once the logic was verified, the circuit was translated into a custom 2-layer PCB to ensure reliability and a compact form factor for mounting.