ESP32-WROOM-32
Beginner Interactive LED Keychain Badge
Overview
A beginner-friendly, standalone interactive LED keychain badge powered by a CR2032 coin cell battery, designed in KiCad using hand-soldering-friendly surface-mount components.
Sakina ZehraSystem architecture
POWER
MCU
- POWER → MCUPowerPower supply
Bill of materials
| Part number | Type | Component | Manufacturer | Package | Qty | Datasheet | Match |
|---|---|---|---|---|---|---|---|
| HC-TYPE-C-24P-FLS-CH5.06-5A-23 | POWER | USB-C Power Jack Power input | HCTL | USB Type-C | 1 | Matched | |
| ESP32-WROOM-32 | MCU | ESP32-WROOM-32 Main controller | Espressif Systems | Reel | 1 | Matched | |
1 alternatives consideredAI verified | |||||||
Build guide
3-5 hoursBeginner
1
Procurement & Preparation
- Source components including the HC-TYPE-C-24P-FLS-CH5.06-5A-23 USB-C Power Jack and ESP32-WROOM-32 module, along with a CR2032 coin cell battery holder and hand-soldering-friendly surface-mount passives.
- Prepare the workstation by cleaning the soldering iron tip, applying flux to the PCB pads, and setting up fume extraction for safe hand soldering.
2
Hardware Assembly & Wiring
- Align and solder the HC-TYPE-C-24P-FLS-CH5.06-5A-23 USB-C Power Jack to the designated pads on the PCB, bridging the power interface to supply 5V and GND.
- Place and solder the ESP32-WROOM-32 module onto the main controller footprint, ensuring proper orientation and solid connections on all castellated pads.
- Install the CR2032 battery holder and remaining surface-mount LEDs and resistors, completing the power and control circuitry.
3
Firmware Setup
- Connect a USB-C cable from your computer to the HC-TYPE-C-24P-FLS-CH5.06-5A-23 port on the badge to establish serial communication with the ESP32-WROOM-32.
- Open the development environment, configure the ESP32 board settings, and flash the interactive LED badge firmware onto the microcontroller.
4
Testing & Calibration
- Insert a CR2032 coin cell battery into the holder and verify that the badge powers on independently from the USB connection.
- Test all interactive LED patterns and button inputs to ensure the badge functions correctly in standalone mode, then complete final visual quality inspection.
Document
Beginner Interactive LED Keychain Badge
A beginner-friendly, standalone interactive LED keychain badge powered by a CR2032 coin cell battery, designed in KiCad using hand-soldering-friendly surface-mount components.
Design Overview
| Item | Details |
|---|---|
| Product Type | Interactive LED Keychain Badge |
| Key Functions | Interactive control via onboard buttons, Controllable RGB LEDs for visual effects, Standalone battery-powered operation |
| Power Source | CR2032 Coin Cell Battery |
| Connectivity | |
| Size | Under 40mm x 40mm keychain size |
| Environment | wearable |
| Difficulty | Beginner |
| Est. Time | 3-5 hours |
System Architecture
Power Topology: USB-C 5V → MCU 3.3V LDO
Module List
| Module ID | Type | Name | Function | Voltage |
|---|---|---|---|---|
| POWER | POWER | USB-C Power Jack | Power input | 5V |
| MCU | MCU | ESP32-WROOM-32 | Main controller | 3.3V |
Design Schemes
Interactive LED Keychain Badge ★
Key IC selection
main MCU and wireless controller
- Need: Provide dual-core processing, sufficient GPIOs for buttons and LED data lines, and integrated Wi-Fi/BLE for potential interactive companion apps.
- Class: Wi-Fi/BLE SoC Module
- Shortlist: Espressif ESP32-WROOM-32, Espressif ESP32-C3-MINI
- Pick: Select based on required GPIO count, RF certification status, and form-factor constraints for a keychain badge.
Li-ion battery charger and power path management
- Need: Safely charge a single-cell Li-ion battery from USB-C 5V and supply a regulated 3.3V to the ESP32 module while handling dynamic load spikes during Wi-Fi transmissions.
- Class: Linear Li-ion Battery Charger with LDO or Buck Regulator
- Shortlist: TP4056 + RT9193, MCP73831 + XC6227, BQ25101
- Pick: Select based on quiescent current, charge current programmability, and thermal dissipation in a small enclosure.
Risk register
| ID | Area | Severity | Detail | Mitigation |
|---|---|---|---|---|
| r1 | power | high | ESP32 peak current during Wi-Fi RF bursts can cause transient voltage drops on a high-impedance battery or poorly regulated 3.3V rail, leading to sudden brownout resets. | Ensure adequate bulk decoupling capacitance (at least 22uF ceramic + 10uF tantalum near the ESP32 power pins) and ensure low-impedance copper traces from the power block. |
| r2 | thermal | med | Driving a large number of RGB LEDs at high brightness inside a sealed plastic keychain badge enclosure can cause localized overheating and discomfort to the user. | Implement firmware-based current limiting / global brightness caps and evaluate thermal dissipation during continuous high-load animations. |
| r3 | emi | med | High-speed data lines for addressable RGB LEDs running close to the ESP32 onboard antenna can cause RF desense or interference during Wi-Fi/BLE operation. | Route LED data lines away from the keep-out zone of the ESP32-WROOM-32 antenna and add a series damping resistor (33-47 ohm) to slow down signal edges. |
Key Components
2/2 modules matched to real parts. See the BOM tab for the full component table.
USB-C Power Jack (HC-TYPE-C-24P-FLS-CH5.06-5A-23)
The candidate MPN matches the primary MPN with a standard packaging/ordering suffix (-23) and the manufacturer 'HCTL' al
ESP32-WROOM-32 (ESP32-WROOM-32)
Exact match to the primary MPN 'ESP32-WROOM-32' from the preferred manufacturer Espressif.
Build Summary
- Difficulty: Beginner
- Estimated time: 3-5 hours
- Tools required: Soldering iron, Lead-free solder, Solder flux, Tweezers, Magnifying glass, Multimeter
See the Build tab for the full step-by-step assembly guide.
Generated by YuanQi AI Design System · Query: Build a beginner-friendly PCB badge in KiCad. First-time designer, needs a simple, complete plan including architecture, BOM, and step-by-step guidance.