Comment concevoir un PCB ESP32 personnalisé à partir de zéro

When many embedded developers, makers, and IoT enthusiasts start learning ESP32 development, they often rely on ready-made development boards for a long time. Cependant, these boards not only contain redundant hardware and have relatively high costs, but also cannot fully meet the requirements of customized projects. If you want to build dedicated IoT devices, low-power sensor terminals, or wireless control modules, independently designing a custom ESP32 PCB is an essential core skill.

This article provides a complete, practical ESP32 PCB customization tutorial designed for beginners, covering the entire process from start to finish. No deep hardware background is required. The tutorial covers everything from requirement planning, sélection des composants, conception schématique, PCB layout and routing, DRC verification, production file export, prototype manufacturing and soldering, to power-on debugging. It strictly follows Espressif’s official hardware design guidelines and is compatible with mainstream PCB fabrication processes. Beginners can follow the steps to successfully create their own ESP32 circuit board while avoiding 90% of the common mistakes made by beginners.

1. Why Design Your Own ESP32 PCB?

Commercially available ESP32 development boards offer strong versatility, but they also come with many limitations that make them unsuitable for highly customized project development:

• Hardware redundancy: Built-in LEDs, boutons, USB-to-serial converters, and unnecessary pin headers occupy valuable board space, making them unsuitable for compact terminal products.
• High power consumption: Fixed power circuits and indicator circuits on development boards cannot be removed, making them unsuitable for low-power IoT projects powered by batteries.
• Cost waste: In mass-production projects, unnecessary hardware modules significantly increase the cost per unit, making large-scale deployment less practical.
• Insufficient flexibility: Users cannot freely customize GPIO assignments, power supply methods, or peripheral interfaces according to project requirements.

By independently designing a customized ESP32 PCB, developers can achieve hardware optimization, extreme miniaturization, low-power optimization, and lower production costs. It is a key step in advancing from “prototype-level development” to “product-level development.” This tutorial uses only open-source and free tools, with no paid barriers, allowing beginners to get started at zero cost.

2. Preparation: Tools, Composants, and Design Guidelines

Before starting the design process, it is necessary to prepare the required tools, identify the core components, and become familiar with official design guidelines. This can avoid repeated PCB revisions later and greatly improve design efficiency.

2.1 Essential Design Tools

This tutorial uses KiCad 7.0+ throughout the entire process. KiCad is a cross-platform open-source PCB design software compatible with Windows, macOS, and Linux. It fully meets the requirements of personal development and small-scale production. Several practical plugins are also used to improve manufacturing compatibility:

• Core software: Latest stable version of KiCad (supports integrated schematic and PCB design, with built-in complete DRC verification)
• Essential plugins:
  • JLCPCB Fabrication Toolkit (one-click export of factory-standard Gerber, Nomenclature, and CPL files)
  • Interactive HTML BOM (generates a visual assembly list for easier soldering)
• Supporting tools: Fiches techniques (Espressif ESP32 official Datasheet, component specifications), calculators (trace width calculation, impedance matching calculation)

Installation tips:
After installing KiCad, search for and install the required plugins through the Plugin Manager. Restart the software for them to take effect. It is recommended to create a dedicated Git repository for the project in advance to maintain version history throughout the development process, prevent file loss, and simplify future revisions.

2.2 Selection of Core Components for the ESP32 Minimum System

For a customized PCB, the priority is to build the ESP32 minimum system first, ensuring that the chip can boot, operate, and connect to the network normally. Additional peripherals can be expanded later according to project requirements.

All core components are selected from commonly available, easy-to-source, low-cost models suitable for mass production:

2.3 Official Core Design Guidelines

Strictly following Espressif’s ESP32 hardware design guidelines is the key to ensuring stable PCB operation and reliable wireless performance. Beginners do not need to deeply understand the theory behind them; simply following these rules is sufficient:

• Power supply requirements: The ESP32 peak operating current can reach 500mA. The 3.3V power traces must be widened to prevent voltage drops that may cause crashes or connection loss.
• Antenna area: Aucune trace, copper pours, or components are allowed within 3mm around the antenna area to ensure RF performance.
• Crystal oscillator layout: The crystal must be placed close to the corresponding chip pins, with the shortest possible traces and proper ground shielding to reduce clock interference.
• Reset circuit: The EN pin must have an external 10kΩ pull-up resistor and a 1μF capacitor RC delay circuit to ensure stable startup after power-on.

3. Step One: Drawing the Complete ESP32 Schematic

The schematic is the core foundation of PCB design. The main principle is: first ensure that the minimum system is complete, then expand peripheral functions. Design step by step to reduce the probability of errors.

3.1 Creating a New Project and Importing Component Libraries

Open KiCad, create a new project, and give it a proper name (recommended format: ESP32_Custom_Project_Name_V1.0). Save it in a dedicated project folder.

Import the official footprint libraries for core components such as the ESP32, CH340, and AMS1117. It is recommended to prioritize official standard footprints to avoid soldering failures caused by footprint mismatches.

3.2 Modular Schematic Design

Divide the circuit into five major functional modules and draw them separately. This makes inspection easier and simplifies future modifications:

1. Power Supply Module

The Micro USB input provides a 5V power supply. After passing through the AMS1117-3.3 voltage regulator, it outputs 3.3V.

UN 10μF electrolytic capacitor et un 0.1μF ceramic capacitor are connected in parallel at the input side, while filtering capacitors are added at the output side to remove high-frequency and low-frequency interference.

Power networks should be consistently labeled as 5V, 3V3, and GND to ensure proper network identification and consistency throughout the design.

2. ESP32 Minimum System Module

Connect the main 3.3V power supply to the ESP32.

Le DANS la broche is connected with a 10kΩ pull-up resistor et un 1Condensateur µF to form an RC reset circuit.

Le 40MHz crystal oscillator is precisely connected to the chip’s clock pins, with matching load capacitors connected on both sides.

All power supply pins should be connected to nearby decoupling capacitors. This is one of the key factors for stable ESP32 operation.

3. Firmware Download and Debugging Module

Use the CH340C to build the USB-to-serial conversion circuit.

Le TX and RX pins are cross-connected to the corresponding ESP32 UART pins. Add current-limiting protection resistors to support firmware flashing and serial log debugging.

Reserve the BOOT button pin to allow manual entry into download mode.

4. Antenna Circuit Module

Select an onboard PCB antenna and arrange the layout according to the official impedance matching requirements.

Reserve positions for impedance matching resistors to maintain strong WiFi/Bluetooth signal performance.

Routing traces and copper pours are strictly prohibited in the antenna area.

5. Peripheral Expansion Module

Reserve GPIO pins, sensor interfaces, relay interfaces, and other expansion resources according to project requirements.

For unused pins, it is recommended to reserve solder pads for future expansion. This avoids the need for redesigning the PCB when adding new functions later.

3.3 Electrical Rule Checking

After completing the schematic design, perform an ERC (Electrical Rules Check).

Focus on identifying the following issues:

• Unconnected pins
• Power short circuits
• Network conflicts
• Incorrect pin definitions
• Other electrical rule violations

Make sure the schematic has zero errors before updating the PCB design with the schematic netlist and entering the PCB layout stage.

4. Step Two: ESP32 PCB Layout and Routing Design

PCB layout and routing directly determine the stability, anti-interference capability, and wireless performance of the circuit board. This is also the stage where beginners are most likely to make mistakes.

Throughout the entire process, strictly follow the principles of:

“Layout first, routing second; power first, signals second; RF priority.”

The design process strictly follows Espressif’s two-layer PCB design guidelines.

4.1 Layer Stackup and Manufacturing Parameter Settings (Suitable for Mass Production)

For beginners, un 2-layer PCB is the preferred choice. It offers the lowest cost, the simplest manufacturing process, and is compatible with standard manufacturing processes from mainstream PCB manufacturers such as JLCPCB and PCBWay.

Recommended parameter settings:

• PCB Layers: 2 couches (top layer for component placement and routing + bottom layer mainly for ground plane)
• Board Thickness: 1.6mm (general industry standard)
• Material: FR-4 (commonly used industrial-grade insulating material)
• Copper Thickness: 1once (35μm, sufficient for ESP32 peak current requirements)
• Surface Finish: HASL (Hot Air Solder Leveling, faible coût, suitable for prototypes and small-batch production)
• Minimum Trace Width / Spacing: 0.15mm
• Minimum Via Diameter: 0.3mm (compatible with standard factory processes)

Core Rules for Two-Layer Boards:

The top layer is responsible for component placement and signal routing.

The bottom layer should contain as few components and traces as possible, while providing a complete ground plane for the RF section, oscillateur à cristal, and main chip.

This significantly improves the PCB’s anti-interference performance.

4.2 Functional Partitioning Layout Principles

The PCB should be divided into functional areas including:

• Power supply area
• Main controller area
• RF area
• Peripheral expansion area
• Programming/download area

This prevents unnecessary interference between different circuits.

1. Core Component Priority

Place the ESP32 main controller chip in the center area as the core of the layout.

This ensures balanced routing distances between different functional modules.

2. Power Supply Placement Close to the Load

The voltage regulator and filtering capacitors should be placed close to the ESP32 power pins.

This shortens the power path and reduces voltage drop and noise interference.

3. Independent RF Area

Place the PCB antenna at the edge of the board in an independent area.

Keep it away from:

• Power circuits
• Crystal oscillator
• Programming/download circuits

This prevents signal interference.

4. Crystal Oscillator Placement

The 40MHz crystal oscillator must be placed directly next to the ESP32 clock pins.

Keep traces as short as possible and provide complete ground shielding around the crystal circuit.

5. Functional Isolation

Separate high-power areas from sensitive circuits such as:

• RF circuits
• Serial communication circuits
• Analog-sensitive signals

Physical isolation helps prevent signal coupling and interference.

4.3 Detailed PCB Routing Guidelines

Routing parameters should be strictly separated into:

• Traces de puissance
• Signal traces
• Traces RF

Beginners can directly follow these standard design parameters:

Power Routing

• 5V and 3.3V power traces should have a width of ≥0.5mm (20mil)
• Ensure sufficient current carrying capability for ESP32 peak operating current
• Prevent overheating and voltage drop problems

Signal Routing

• General GPIO and UART signal traces:
  • Largeur: 0.2–0.25mm (10mil)
  • Keep traces short and straight
  • Minimize unnecessary bends

RF Routing

• Antenna traces must maintain 50Ω impedance matching
• Keep routing smooth
• Avoid sharp corners and right-angle bends
• Keep RF traces away from interference sources

Routing Restrictions

Avoid the following:

• ❌ 90-degree trace corners
• ❌ Excessively long jumper traces
• ❌ Signal traces crossing power areas
• ❌ Routing traces or copper underneath the antenna area

4.4 Copper Pour, Ground Vias, and Final Optimization

After completing routing, perform final optimization to improve PCB stability and anti-interference capability.

1. Full Ground Plane Pour

• Add copper pour to unused areas on the top layer.
• Create a complete GND copper plane on the bottom layer.
• Build a continuous ground reference plane.

2. Dense Ground Via Placement

Add multiple ground vias around:

• ESP32 chip area
• Crystal oscillator area
• RF area

These vias connect the top and bottom ground layers, reducing ground impedance.

3. Add Teardrops

Apply teardrops to:

• All pads
• All vias

This improves mechanical strength during soldering and prevents:

• Broken connections
• Pad damage
• Soldering failures

4. Clean Silkscreen Design

Standardize:

• Component reference labels
• Pin markings
• Version information

A clean silkscreen improves readability and makes soldering and debugging easier.

5. Define Keepout Areas

Lock the antenna keepout region to prevent accidental modifications during later editing.

4.5 DRC Design Rule Verification

After completing all optimization steps, run the RDC (Design Rule Check).

The following items must be verified:

• Largeur de trace
• Espacement des traces
• Par diamètre
• Copper clearance
• Electrical shorts
• Other manufacturing rule violations

The PCB should achieve:

• Zero errors
• Zero warnings

This eliminates hidden hardware problems and is a key factor in ensuring the board powers on successfully on the first attempt.

5. Step Three: Production File Export and PCB Manufacturing Practice

After completing the PCB design, production files recognized by PCB manufacturers must be exported.

With the corresponding plugins, standard manufacturing files can be generated with one click, ensuring compatibility with mainstream PCB fabrication processes.

5.1 One-Click Export of Gerber + Nomenclature + CPL Files

Using the previously installed JLCPCB Fabrication Toolkit plugin, export all required production files in batches:

Fichiers Gerber

Contain:

• Top copper layer
• Bottom copper layer
• Silkscreen layers
• Solder mask layers
• Board outline

These are the core files required for PCB manufacturing.

BOM File (Nomenclature)

Automatically generates:

• Component models
• Reference designators
• Quantities

Used for:

• Component purchasing
• Batch assembly

CPL File (Component Placement List)

Contains component placement coordinates.

Used for:

• Factory SMT assembly production

Package all exported files into a ZIP archive.

No additional parameter modification is required. The package can be directly submitted to the PCB manufacturer.

5.2 Manufacturing Order Parameter Verification

Taking JLCPCB as an example:

After uploading the ZIP package, the system automatically identifies:

• Number of layers
• Board dimensions
• Hole sizes

Beginners can use the following standard parameters:

• Calques: 2 couches
• Taille: Custom (default designed size)
• Material: FR-4
• Board Thickness: 1.6mm
• Copper Thickness: 1once
• Surface Finish: HASL
• Solder Mask Color: Green (general standard)
• Assemblée CMS: Facultatif (beginners can manually solder without SMT assembly)

The most important step is checking the automatically detected:

• Largeur de trace
• Hole diameter

If these match the original design requirements, the order can be submitted.

Prototype boards can usually be received within 3–5 days.

6. Step Four: Soldering, Power-On Testing, and Functional Debugging

After receiving the PCB prototypes, follow a standardized soldering and debugging process.

Troubleshoot problems step by step to avoid situations where faults cannot be located after completing the entire board assembly.

6.1 Step-by-Step Soldering Process

1. Step One: Solder the Power Supply Circuit

Solder the USB connector, voltage regulator chip, and filtering capacitors.

Perform an independent power-on test and measure whether the 3.3V output voltage is stable.

Confirm that there are:

• No short circuits
• No abnormal voltage drops

2. Step Two: Solder the Minimum System

Solder:

• ESP32 chip
• Crystal oscillator
• Reset circuit

Power on again and measure whether the voltage on the chip’s power pins is within the normal range.

3. Step Three: Solder the Debugging Circuit

Solder:

• CH340 programming circuit
• Buttons
• Indicator LEDs

4. Step Four: Solder Peripheral Circuits

Enfin, solder expansion peripherals such as:

• Capteurs
• Relays
• Other external modules

Troubleshoot each section step by step.

6.2 Core Function Testing and Debugging

Test d'alimentation

Use a multimeter to measure:

• 5V voltage
• 3.3V voltage

Ensure:

• Accurate voltage output
• Stable voltage
• No short-circuit heating problems

Programming Test

Install the CH340 driver on the computer.

Connect the USB cable and confirm that the serial port is recognized in Device Manager.

Successfully flash a basic ESP32 program.

Communication Test

Flash a WiFi scanning program.

Test:

• Wireless signal stability
• No unexpected disconnections
• No weak signal issues

Peripheral Test

Test the following functions one by one:

• GPIO
• UART
• Sensor interfaces

Ensure all peripherals operate normally.

6.3 Common Beginner Problems and Quick Troubleshooting

Power-On Short Circuit and Overheating

Possible causes:

• Positive and negative power short circuit
• Reverse installation of capacitors

Solution:

Prioritize checking the power supply circuit soldering.

Unable to Upload Firmware

Vérifier:

• CH340 soldering quality
• Whether TX/RX lines are cross-connected correctly
• Whether the BOOT button circuit works properly

Repeated Restarting After Power-On

Possible causes:

• Insufficient 3.3V power supply current
• Missing filtering capacitors
• Abnormal RC reset circuit

Focus on checking:

• Power supply module
• Reset module

Weak WiFi Signal / Frequent Disconnection

Possible causes:

• Copper pour or routing inside the antenna area
• Crystal traces without proper grounding
• RF interference

Solution:

Compare with the recommended layout guidelines and correct the PCB design.

7. Beginner Must-Read: 10 Common ESP32 PCB Design Mistakes to Avoid

Based on official guidelines and practical experience, the following are the most common mistakes beginners make.

Avoiding them can significantly improve the first-pass success rate.

1.Strictly prohibit routing traces, copper pouring, or placing components within 3mm of the antenna area.

RF performance directly determines communication stability.

2.Le 3.3V power trace must be widened.

Do not use thin traces.

Insufficient current capacity may cause:

• System crashes
• Unexpected restarts

3.Every ESP32 power pin must have nearby decoupling capacitors.

They cannot be omitted.

This prevents power supply interference.

4.The EN pin must include an RC reset circuit.Otherwise, abnormal power-on timing may occur, resulting in unstable startup.

5.The crystal oscillator traces must be:

• As short as possible
• Fully surrounded by ground
• Kept away from power circuits and high-power components

This prevents clock interference.

6.Strictly separate:

• Power areas
• RF signal areas

Avoid interference between strong and weak signals.

7.For two-layer PCBs:

The bottom layer should contain as few components and traces as possible.

Maintain a complete ground plane to improve anti-interference performance.

8.Avoid:

• 90-degree signal traces
• Sharp-angle routing

This prevents signal reflection and interference.

9.After copper pouring, add sufficient ground vias to connect ground layers.

This reduces ground impedance and improves stability.

10.Always complete both:

• ERC verification
• DRC verification

This prevents hidden electrical and manufacturing errors.

8. Advanced Optimization: Upgrading from Prototype PCB to Product-Level PCB

After completing the basic prototype design, the following optimizations can upgrade the ESP32 PCB to a production-ready version suitable for commercial projects:

Low-Power Optimization

• Add power switching circuits
• Add power-off detection circuits
• Remove unnecessary indicator LEDs

Suitable for battery-powered devices.

Stability Optimization

Upgrade to a 4-layer PCB design:

• Separate power layers
• Dedicated ground layers
• Independent signal layers

Provides extreme anti-interference performance.

Protection Optimization

Ajouter:

• ESD protection circuits
• TVS surge protection circuits

Protect GPIO and UART pins.

Mass Production Optimization

• Standardize component footprints
• Select common production part numbers
• Optimize layout for automated SMT assembly

Functional Expansion

Ajouter:

• Bluetooth antenna matching circuits
• Sensor adaptation circuits
• Redundant voltage regulation circuits

Support more complex application scenarios.

9. Résumé

Designing a custom ESP32 PCB is not an exclusive skill limited to experienced hardware engineers.

With zero hardware background, beginners can independently complete a full design process from schematic creation to production prototype by following:

• Standardized component selection
• Modular schematic design
• Functional partitioned layout
• Compliant PCB routing
• Strict verification procedures

This complete practical workflow strictly follows Espressif’s official hardware design guidelines and is compatible with mainstream PCB manufacturing processes.

From minimum system construction, débogage fonctionnel, troubleshooting, and optimization, this tutorial provides full coverage.

It not only helps you quickly create your own ESP32 circuit board but also builds a solid foundation in embedded hardware design, enabling advancement from a “code-only developer” to a full-stack hardware and software developer.