EasyEDA Arduino Library: Design Custom Shields for Uno, Mega & Nano

As someone who has designed over 40 custom Arduino shields in the past seven years, I can tell you that the EasyEDA Arduino workflow has completely revolutionized how makers and engineers approach PCB design. Gone are the days of expensive software licenses and frustrating learning curves. Today, anyone with basic electronics knowledge can design and manufacture professional-quality shields using free, browser-based tools.

This comprehensive guide walks you through everything needed to design custom shields for Arduino Uno, Mega, and Nano using EasyEDA’s extensive component library and integrated manufacturing services.

Why EasyEDA is Perfect for Arduino Shield Design

When I started designing shields back in 2017, I used Eagle CAD. It worked, but creating accurate Arduino footprints was tedious and error-prone. The Arduino Uno EasyEDA library changed everything for me. Here’s why this combination works so well:

Massive Community Library: EasyEDA’s user-contributed component library contains hundreds of Arduino-related parts. Search for “Arduino Uno” and you’ll find complete shield templates with verified footprints ready to use. No more spending hours creating pin headers from scratch.

Cloud-Based Convenience: Your designs are saved online, accessible from any computer. I’ve made last-minute design changes from hotel rooms before production deadlines. Try doing that with desktop-only software.

Direct JLCPCB Integration: Since EasyEDA and JLCPCB are sister companies, ordering manufactured PCBs takes literally one click. The Gerber files are generated automatically in the correct format.

Zero Cost: Unlike Altium ($355/year) or even Eagle’s paid tiers, EasyEDA Arduino design capabilities are completely free. For hobbyists and startups, this matters enormously.

Understanding Arduino Board Specifications

Before you can design a shield, you must understand the physical and electrical specifications of your target board. Getting dimensions wrong by even a millimeter means your shield won’t fit.

Arduino Uno R3 Specifications

The Arduino Uno remains the most popular board for shield development. Here are the critical specifications:

Specification	Value	Notes
Board Dimensions	68.6mm × 53.4mm	2.7″ × 2.1″
Digital I/O Pins	14 (D0-D13)	6 provide PWM
Analog Input Pins	6 (A0-A5)	10-bit resolution
Operating Voltage	5V	Logic level
Input Voltage	7-12V	Via barrel jack
DC Current per Pin	20mA	40mA absolute max
Header Pitch	2.54mm	Standard 0.1″

The Critical Pin Spacing Issue: The distance between digital pins D7 and D8 is 160 mil (4.064mm), not the standard 100 mil (2.54mm) used elsewhere. This was reportedly a layout mistake in the original Arduino design that became a permanent “feature.” Every Arduino EasyEDA shield template must account for this quirk.

Arduino Mega 2560 Specifications

The Arduino Mega EasyEDA workflow follows similar principles but with an expanded form factor:

Specification	Value	Notes
Board Dimensions	101.6mm × 53.4mm	4″ × 2.1″
Digital I/O Pins	54	15 provide PWM
Analog Input Pins	16	A0-A15
Serial Ports	4	Hardware UART
I2C Location	Pins 20-21	Different from Uno
SPI Location	Pins 50-53	Different from Uno

The Mega maintains the same core header positions as the Uno for basic shield compatibility, plus extended headers for the additional I/O. Shields designed for Uno will work on Mega, but not vice versa.

Arduino Nano Specifications

The Nano uses a completely different form factor—it’s a DIP-style module that plugs into a carrier board rather than having shields stack on top:

Specification	Value	Notes
Board Dimensions	45mm × 18mm	Compact form factor
Pin Configuration	2×15 pins	30 total
Pin Pitch	2.54mm	Standard throughout
Row Spacing	15.24mm	600 mil DIP-style
Operating Voltage	5V	Same as Uno

Finding Arduino Components in EasyEDA Library

The strength of EasyEDA Arduino Uno design lies in its extensive component library. Here’s how to find and evaluate the right parts.

Search Strategy for Best Results

Different search terms yield different results. Use this guide:

Search Term	Results Type	Best Use Case
“Arduino Uno Shield”	Complete shield templates	Starting new shield projects
“Arduino Uno R3”	Full board footprints	Carrier board designs
“Arduino Uno Header”	Individual connectors	Custom configurations
“Arduino Mega Shield”	Mega-sized templates	Large I/O projects
“Arduino Mega 2560”	Mega board footprints	Reference designs
“Arduino Nano”	Nano module footprints	Embedded projects
“Arduino Nano Carrier”	Nano breakout templates	Custom carrier boards

Evaluating Library Components

Not all community-contributed parts are reliable. Before using any component, verify these criteria:

Check for Both Symbol and Footprint: Some parts only include schematic symbols without PCB footprints, or vice versa. You need both. Click “Open in Editor” to verify.

Review Usage Count: Parts with higher “Open in Editor” counts have been tested by more users. A count above 5 generally indicates reliability.

Verify Dimensions: Compare the footprint against official Arduino documentation. Even popular parts sometimes have errors.

Check Pin Labels: Ensure pins are labeled correctly (D0-D13, A0-A5, etc.) and match the official pinout.

Look for 3D Models: Parts with 3D models help verify clearances and visualize the final product.

Step-by-Step: Designing an Arduino Uno Shield

Let me walk you through a complete Arduino Uno EasyEDA shield design from start to finish. This process applies to Mega and Nano designs with appropriate modifications.

Phase 1: Project Setup

Create a New Project:

1. Log into EasyEDA (register free if needed)
2. Click “+ New Project” in the left panel
3. Name your project descriptively: “Motor_Driver_Shield_v1”
4. Click “New Schematic” to begin

Set Up Your Workspace:

• Enable grid snapping (10mil or 0.254mm works well)
• Set appropriate zoom level (usually 100-200%)
• Familiarize yourself with keyboard shortcuts (W for wire, R for resistor, etc.)

Phase 2: Schematic Design

Place the Arduino Shield Template:

1. Press “L” or click the library icon
2. Search “Arduino Uno Shield”
3. Select a well-rated template with both schematic symbol and PCB footprint
4. Click to place in your schematic

The template should display all Arduino pins organized logically: digital pins (D0-D13), analog pins (A0-A5), power pins (5V, 3.3V, GND, VIN), and special pins (RESET, IOREF, AREF).

Add Your Circuit Components:

Now add the components that define your shield’s functionality. For a motor driver example:

1. Search for your motor driver IC (L298N, TB6612FNG, DRV8833)
2. Add supporting passive components (decoupling capacitors, flyback diodes)
3. Include connectors for motor outputs and external power
4. Add any indicator LEDs and current-limiting resistors

Important consideration: If you plan to use JLCPCB’s SMT assembly service, select components from the LCSC library marked “JLCPCB Assembled.” This ensures the parts are available for automated assembly.

Wire the Circuit:

1. Click on a component pin to start a wire
2. Route to the destination pin
3. Wires connecting at junctions automatically create net connections
4. Name important nets for clarity (right-click → Set Net Name)

Add Component Values: Double-click each component to set appropriate values:

• Resistors: “10K”, “220R”, “4.7K”
• Capacitors: “100nF”, “10uF”, “1000uF”
• ICs: Full part number like “L298N” or “TB6612FNG”

Phase 3: PCB Layout

Convert Schematic to PCB:

1. Save your schematic
2. Click “Design” → “Convert to PCB” or use the toolbar button
3. EasyEDA creates a new PCB file with all components placed outside the board outline
4. Blue “ratlines” show the connections that need routing

Define the Board Outline:

This step is critical for Arduino EasyEDA shields:

1. Switch to the “BoardOutline” layer in the Layers panel
2. Delete the default rectangular outline
3. Draw your new outline matching Arduino dimensions

For a standard Uno shield:

• Width: 53.4mm (2.1″)
• Length: 68.6mm (2.7″) or shorter if components allow
• Use the Arc tool for rounded corners (typically 3mm radius)

Position the Headers:

The Arduino header positions must be exact. Use these coordinates (with board origin at lower-left corner):

Header	Function	Position Notes
J1 (8-pin)	Power	Lower edge, includes IOREF, RESET, 3.3V, 5V, GND, GND, VIN
J2 (6-pin)	Analog	Adjacent to J1, includes A0-A5
J3 (8-pin)	Digital Low	Upper edge, includes D0-D7
J4 (10-pin)	Digital High	Adjacent to J3, includes D8-D13 plus SCL, SDA, AREF, GND

Remember: The gap between J3 and J4 is 160 mil (4.064mm), not 100 mil!

Place Your Components:

1. Drag components into their intended positions
2. Keep related components together
3. Place decoupling capacitors close to IC power pins
4. Orient components for easy hand soldering if needed
5. Maintain clearance from header positions

Route the Traces:

You can use EasyEDA’s auto-router or route manually:

Auto-routing:

1. Click “Route” → “Auto Route”
2. Review results and fix any issues
3. Auto-routing works well for simple designs

Manual routing (recommended for critical signals):

1. Select the “Track” tool
2. Click on a pad to start routing
3. Click to create corners
4. Double-click to finish

Routing Guidelines for Shields:

Signal Type	Recommended Trace Width	Notes
Power (5V, VIN)	20-40 mil (0.5-1mm)	Handle higher currents
Ground	20-40 mil	Use ground plane when possible
Digital signals	10-12 mil (0.25-0.3mm)	Standard signal routing
Analog signals	10-12 mil	Keep short, away from noise
High-speed signals	10 mil	Consider impedance matching

Add Ground Plane:

1. Select the bottom layer
2. Use “Copper Area” tool
3. Draw around the board outline
4. Set the net to “GND”
5. The plane automatically connects to all GND pads

Phase 4: Finishing Touches

Add Silkscreen:

• Project name and version
• Pin labels for connectors
• Component orientation markers
• Your name or company logo

Add Mounting Holes: Standard Arduino shields have mounting holes at specific locations. If your template doesn’t include them:

1. Select “Hole” tool
2. Set diameter to 3.2mm (for M3 screws)
3. Place at Arduino-specified positions

Run Design Rule Check (DRC):

1. Click “Design” → “Design Rule Check”
2. Fix any errors (shorts, clearance violations)
3. Review warnings (some may be acceptable)

Preview in 3D:

1. Click “3D View”
2. Check component heights
3. Verify no interference with Arduino USB/power connectors
4. Confirm overall appearance

Designing Arduino Mega Shields

The Arduino Mega EasyEDA process is similar to Uno shields with these key differences:

Extended Form Factor

The Mega shield extends 33mm beyond the Uno’s length to accommodate additional headers:

Area	Pins	Function
Standard (Uno-compatible)	D0-D13, A0-A5	Basic I/O
Extended Digital	D22-D53	Additional digital I/O
Extended Analog	A6-A15	Additional analog inputs
Communication	Pins 14-21	Serial1-3, I2C

Communication Pin Differences

Be aware that some communication interfaces are in different locations:

Interface	Arduino Uno	Arduino Mega
I2C SDA	A4	Pin 20
I2C SCL	A5	Pin 21
SPI MOSI	Pin 11	Pin 51
SPI MISO	Pin 12	Pin 50
SPI SCK	Pin 13	Pin 52
SPI SS	Pin 10	Pin 53

Shields designed for Mega-specific features won’t work on Uno. For maximum compatibility, design for Uno pinout when possible.

Designing Arduino Nano Carrier Boards

Arduino Nano “shields” are actually carrier boards—the Nano plugs into the carrier rather than the other way around.

Nano Form Factor Approach

Search EasyEDA for “Arduino Nano” to find appropriate footprints. The Nano uses standard 600-mil DIP spacing, making footprint creation straightforward.

Design Approach:

1. Place female headers (2×15 pin, 2.54mm pitch, 15.24mm row spacing)
2. Route from header pins to your circuit
3. Add any required power regulation (Nano can be powered via USB, VIN, or 5V pin)

Nano Pin Mapping Reference

Pin	Function	Special Features
D0	Digital I/O	RX (Serial)
D1	Digital I/O	TX (Serial)
D2-D12	Digital I/O	D3,5,6,9,10,11 have PWM
D13	Digital I/O	Built-in LED
A0-A5	Analog Input	Also usable as digital
A6-A7	Analog Input	Input only
VIN	Power Input	7-12V
5V	Power	Regulated output/input
3.3V	Power	Limited current
GND	Ground	Multiple pins
RST	Reset	Active low
REF	Reference	For ADC reference

Common Design Mistakes and Solutions

After reviewing hundreds of forum posts and troubleshooting my own designs, here are the most frequent issues:

Mistake 1: Incorrect Header Spacing

The Problem: Shield doesn’t fit on Arduino due to wrong spacing between D7-D8 headers.

The Solution: Always use verified shield templates from the EasyEDA library. If creating custom headers, ensure the 160-mil gap is correct.

Mistake 2: Height Clearance Issues

The Problem: Tall components block USB connector or prevent shield stacking.

The Solution: Keep components under 10mm in areas that overlap the Arduino. Check 3D preview before manufacturing.

Mistake 3: Insufficient Power Traces

The Problem: Voltage drops or overheating on power connections.

The Solution: Use 20-40 mil traces for power. For motor shields, use even wider traces or copper pours.

Mistake 4: Missing Decoupling Capacitors

The Problem: Noise issues, erratic behavior, IC failures.

The Solution: Add 100nF ceramic capacitors near every IC’s power pins. Add bulk capacitors (10-100uF) at power entry points.

Mistake 5: No Pass-Through for Stacking

The Problem: Shield blocks access to unused Arduino pins.

The Solution: Use stackable headers that pass signals through to the next shield.

Manufacturing Your Shield

Generating Production Files

Once your design is complete:

1. Run final DRC to catch any errors
2. Click “Fabrication” → “PCB Fabrication File (Gerber)”
3. Download the generated ZIP file (for manual ordering)
4. Or click “Order at JLCPCB” for direct ordering

JLCPCB Order Options

Option	Typical Choice	Notes
Layers	2	Most shields are 2-layer
PCB Thickness	1.6mm	Standard Arduino thickness
PCB Color	Green	Cheapest; other colors available
Surface Finish	HASL	Lead-free HASL recommended
Quantity	5-10	Minimum order 5 pieces

Typical Costs:

• 5 pcs, 2-layer, 100×100mm or less: ~$2 + shipping
• SMT assembly (basic parts): Add ~$8-15 setup + part costs

Essential Resources and Links

Here are the key resources for EasyEDA Arduino shield design:

Resource	URL	Purpose
EasyEDA Editor	easyeda.com/editor	Standard design tool
EasyEDA Pro	pro.easyeda.com	Advanced features
Component Library	easyeda.com/components	Search Arduino parts
OSHWLab	oshwlab.com	Open source projects
JLCPCB Ordering	jlcpcb.com/quote	PCB manufacturing
LCSC Components	lcsc.com	Component purchasing
Arduino Documentation	docs.arduino.cc	Official specifications
Arduino Hardware	github.com/arduino	Official design files
EasyEDA Tutorials	docs.easyeda.com	Official documentation

Recommended Templates to Start With

Search for these highly-used templates in EasyEDA:

• “Arduino Uno Shield Template”
• “Arduino Uno R3 Shield”
• “Arduino Mega Shield”
• “Arduino Nano Breakout”
• “Arduino Proto Shield”

Frequently Asked Questions

Can I design a shield that works on both Arduino Uno and Mega?

Yes, absolutely. Since the Arduino Mega maintains backward compatibility with Uno shields, any shield designed for the Uno footprint will work on Mega. The core header positions (D0-D13, A0-A5, power) are identical on both boards. However, you won’t have access to the Mega’s extended I/O pins (D22-D53, A6-A15) unless you design specifically for the larger Mega form factor. For maximum compatibility, I recommend designing for the Uno footprint and adding Mega-specific features only when necessary.

Why doesn’t my shield fit properly on my Arduino?

The most common cause is incorrect spacing between the D7-D8 digital headers. This gap must be 160 mil (4.064mm), not the standard 100 mil (2.54mm) used elsewhere on the board. Other possible causes include incorrect overall dimensions, wrong pin pitch (should be 2.54mm), or using a pre-R3 template on an R3 board. Always use verified templates from the EasyEDA library and double-check dimensions against official Arduino documentation before manufacturing.

How do I add JLCPCB SMT assembly to my shield design?

First, select components from the LCSC library that have “JLCPCB Assembled” designation when designing your schematic. When you’re ready to order, generate the Gerber files as normal, then also export the BOM (Bill of Materials) and CPL (Component Placement List) files from EasyEDA’s Fabrication menu. During JLCPCB checkout, enable SMT assembly and upload these files. The system will match your components and show pricing. Stick to “Basic” parts when possible to minimize assembly fees—each unique “Extended” part adds $3 to your order.

What’s the difference between EasyEDA Standard and Pro editions for shield design?

EasyEDA Standard is completely free and handles most Arduino shield designs perfectly. It supports up to 300 devices or 1000 pads per design, includes simulation capabilities, and has full access to the community library. EasyEDA Pro is also free but offers advanced features like support for 3000+ devices, more rigorous design constraints, hierarchical schematics, and better team collaboration tools. For typical Arduino shields with under 50 components, Standard edition is more than sufficient. Use Pro if you’re designing complex multi-sheet projects or need advanced verification features.

How do I create a custom component if I can’t find it in the library?

EasyEDA makes custom component creation straightforward. Go to “Library” → “New Component” and create the schematic symbol by placing pins and drawing the outline. Then create the corresponding PCB footprint with accurate pad dimensions and spacing—measure your actual component or use the datasheet. Link the symbol and footprint together, and save to your personal library. For Arduino-specific components, measure carefully against official Arduino boards, as even small errors compound across multiple pins. Once created, your custom parts can be reused in future projects and even shared with the community.

Advanced Tips for Professional Results

Design for Manufacturing (DFM)

Follow these guidelines for reliable manufacturing:

Parameter	Minimum	Recommended
Trace Width	6 mil	10 mil
Trace Spacing	6 mil	10 mil
Via Hole	0.3mm	0.4mm
Via Diameter	0.6mm	0.8mm
Pad Size	1.2mm	1.5mm
Silkscreen Width	4 mil	6 mil

Thermal Management

For shields with power components (motor drivers, voltage regulators):

• Use thermal vias under power pads
• Add copper pours for heat spreading
• Consider component placement for airflow
• Derate current capacity at high temperatures

Signal Integrity

For shields with high-speed or sensitive signals:

• Keep analog and digital signals separated
• Route sensitive signals away from power traces
• Use ground planes for return paths
• Consider adding filtering at signal entry points

Real-World Shield Project Examples

To help solidify these concepts, here are practical project ideas at different skill levels that demonstrate Arduino EasyEDA design principles.

Beginner Project: LED Matrix Shield

Objective: Create an 8×8 LED matrix display shield for Arduino Uno.

Key Learning Points:

• Current-limiting resistor calculations
• Multiplexing concepts for LED control
• Basic trace routing for moderate pin counts
• Silkscreen labeling for orientation

Components Required:

• 8×8 LED matrix module or 64 individual LEDs
• 8× current-limiting resistors (typically 220Ω)
• 8× NPN transistors for row driving (optional)
• Pin headers for Arduino connection

This project teaches fundamental shield design without complex power considerations.

Intermediate Project: Motor Driver Shield

Objective: Design a dual H-bridge motor driver shield capable of driving two DC motors or one stepper motor.

Key Learning Points:

• Power trace sizing for motor currents
• Flyback diode placement for inductive loads
• Separate power input for motors
• Heat dissipation considerations

Components Required:

• L298N or TB6612FNG motor driver IC
• Flyback diodes (if using L298N)
• Decoupling capacitors (100nF + 100uF)
• Screw terminals for motor connections
• Separate power input connector

This Arduino Uno EasyEDA project introduces power electronics concepts critical for robotics applications.

Advanced Project: Data Logger Shield

Objective: Create a comprehensive data logging shield with SD card storage, real-time clock, and sensor inputs.

Key Learning Points:

• Multiple communication protocols (SPI for SD, I2C for RTC)
• Battery backup circuit design
• Level shifting considerations
• File system requirements

Components Required:

• SD card socket (SPI interface)
• DS3231 RTC module (I2C)
• CR2032 battery holder
• Multiple sensor connectors
• Status LEDs

This project demonstrates how to integrate multiple subsystems on a single Arduino EasyEDA shield.

Testing and Debugging Your Shield

Pre-Manufacturing Verification

Before ordering PCBs, perform these checks:

Electrical Review Checklist:

• All required connections present (no missing ratlines)
• No unintended shorts between nets
• Power and ground properly connected
• Decoupling capacitors near every IC
• Pull-up/pull-down resistors where needed

Mechanical Review Checklist:

• Board outline matches Arduino dimensions
• Headers at correct positions
• Component heights won’t interfere with stacking
• Mounting holes aligned (if included)
• Text readable and correctly oriented

DRC Verification:

• No clearance violations
• No unrouted connections
• No floating copper
• Minimum trace widths met

Post-Manufacturing Testing

When your shields arrive, follow this systematic testing procedure:

Visual Inspection:

1. Check for manufacturing defects (shorts, opens, missing copper)
2. Verify silkscreen legibility
3. Confirm component footprints match your parts

Continuity Testing (before soldering):

1. Test for shorts between power rails (5V-GND, 3.3V-GND)
2. Verify header pin connectivity to intended traces
3. Check mounting holes are properly isolated

Functional Testing (after assembly):

1. Power the shield without connecting to Arduino—check for overheating
2. Connect to Arduino and run a basic test sketch
3. Verify each I/O function individually
4. Test under expected operating conditions

Version Control and Documentation

Professional development requires good documentation habits:

Project Documentation Essentials

Document	Contents	When to Create
Schematic PDF	Complete circuit diagram	After schematic finalized
BOM Spreadsheet	All components with values and part numbers	Before ordering
Pin Mapping	Which Arduino pins your shield uses	During design
Assembly Notes	Special soldering instructions	Before assembly
Test Procedure	Steps to verify functionality	Before testing
Revision History	Changes between versions	Each revision

EasyEDA Project Organization

Keep your designs organized:

1. Use descriptive names: “Motor_Shield_v2.1” not “shield_final_final”
2. Add project descriptions: Note target Arduino and key features
3. Create folders: Group related schematics and PCBs
4. Archive each version: Before major changes, save a copy
5. Export regularly: Keep local backups of critical projects

Conclusion

The EasyEDA Arduino ecosystem has democratized PCB design for the maker community. Whether you’re creating your first Arduino Uno EasyEDA shield or designing complex Arduino Mega EasyEDA expansion boards, the tools are accessible, the libraries are extensive, and the manufacturing path is straightforward.

My advice for beginners: start with a simple project. Design a basic shield with a few LEDs and buttons, go through the complete workflow, and get physical boards in your hands. The learning from that first project is invaluable, and the cost is minimal—often under $10 for your first batch.

For experienced designers, EasyEDA offers enough capability to replace expensive commercial tools for many applications. The community library grows daily, team collaboration features support professional workflows, and the direct JLCPCB integration streamlines manufacturing.

The Arduino ecosystem continues to evolve with new boards like the Uno R4 and Nano ESP32, and the EasyEDA library keeps pace with community-contributed templates for each new platform. Whatever shield you’re imagining, the tools to build it are ready and waiting.