4 layers58.3 × 26.2 mm
2 layers33.3 × 36.5 mm
A compact USB digital microphone development board built around the Raspberry Pi RP2040 microcontroller and the STMicroelectronics MP34DT05TR-A digital MEMS microphone.
- Size
- 33.3 × 36.5 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 28
- Nets
- 64
- Pads
- 168
- Tracks, vias
- 741, 88
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 15 Jul 2026
- Updated
- 3 Aug 2026
Overview
Mic is an open-source printed circuit board by joshitha-c, from the joshitha-c/microphone repository on GitHub. It is a 2-layer board of 33.3 × 36.5 mm with 28 parts on 64 nets, routed with 741 tracks and 88 vias.
It is built around the RP2040, W25Q128JVEIQ and USBLC6-2P6, with the MP34DT05TR-A among its other parts. Its parts include 11 capacitors, 6 resistors, 4 ICs, 2 connectors and 2 switches. It belongs with the RP2040 boards of this library.
Main components
4
RP2040
LQFN-56(7x7)12bit 133MHz 30 LQFN-56(7x7) Microcontrollers (MCU/MPU/SOC) ROHSRaspberry PiMicrocontrollers (MCU/MPU/SOC)
W25Q128JVEIQ
WSON-8-EP(6x8)-40℃~+85℃ 100,000 cycles 10uA 128Mbit 133MHz 2.7V~3.6V 20 Years Power-on reset、Hardware write protection、Software write protection、Write enable latch、Absolute write protection、Power lock protection SPI WSON-8-EP(6x8) NOR FLASH ROHSWinbondNAND FLASH
USBLC6-2P6
SOT-666-6-40℃~+125℃ 150nA 17V 2 3.5pF 5.25V 5A@8/20us 6V ESD IEC 61000-4-2 Unidirectional SOT-666-6 ESD and Surge Protection (TVS/ESD) ROHSSTMicroelectronicsESD And Surge Protection (TVS/ESD)
MP34DT05TR-A
HCLGA-4LD(3x4)-26dB -40℃~+85℃ 1.8V 1mm 3mm 4mm 64dB 650uA Omnidirectional Omnidirectional pickup HCLGA-4LD(3x4) MEMS Microphones ROHSSTMicroelectronicsMEMS Microphones
README
README.mdRP2040 USB MEMS Microphone Board
A compact USB digital microphone development board built around the Raspberry Pi RP2040 microcontroller and the STMicroelectronics MP34DT05TR-A digital MEMS microphone.
The board captures audio using a PDM microphone, converts it to PCM on the RP2040, and streams audio over USB to a host computer. It serves as a reference platform for USB Audio Class (UAC) applications, embedded audio processing, and voice-enabled IoT projects.
Features
- Raspberry Pi RP2040 dual-core Cortex-M0+ MCU
- MP34DT05TR-A digital PDM MEMS microphone
- USB Type-C interface
- USB Audio Device support
- External QSPI Flash memory
- 3.3 V regulated power supply
- BOOTSEL and RESET buttons
- SWD debug/programming header
- Designed in KiCad
Hardware Overview
Microcontroller
RP2040
Features:
- Dual-core ARM Cortex-M0+ @ 133 MHz
- 264 KB SRAM
- USB 1.1 Device/Host
- PIO (Programmable I/O)
- DMA Controller
- SPI / I²C / UART
- ADC
The RP2040 handles:
- PDM microphone sampling
- PDM-to-PCM conversion
- USB Audio streaming
- Audio processing
- Flash storage access
Digital Microphone
MP34DT05TR-A
Features:
- Digital PDM output
- Omnidirectional MEMS microphone
- Low power consumption
- High signal-to-noise ratio
- 3.3 V operation
Connections:
| Signal | RP2040 |
|---|---|
| CLK | GPIO |
| DOUT | GPIO |
| VDD | 3.3 V |
| GND | GND |
USB Interface
USB Type-C connector
Supports:
- USB Device
- Power input (5 V)
- USB Audio Class (UAC)
- Firmware upload
- Serial communication (optional)
External Flash
Winbond W25Q128JV
Features:
- 128 Mbit (16 MB)
- QSPI Interface
- Firmware storage
- User data storage
Power Supply
Input:
- USB Type-C (5 V)
Regulator:
- LD1117-3.3 V LDO
Outputs:
- 3.3 V system rail
Buttons
BOOTSEL
Places the RP2040 into USB bootloader mode for firmware programming.
RESET
Resets the microcontroller.
Debug Interface
SWD Header
Provides:
- SWCLK
- SWDIO
- 3.3 V
- GND
Compatible with:
- Raspberry Pi Debug Probe
- CMSIS-DAP
- Picoprobe
Applications
- USB microphone
- Voice assistant
- Speech recognition
- Audio data logger
- Acoustic monitoring
- Smart home devices
- Embedded DSP experiments
Future Improvements
- Stereo microphone support
- I²S audio output
- On-board headphone amplifier
- MicroSD recording
- RGB status LED
Bill of Materials (Major Components)
| Reference | Part |
|---|---|
| U5 | RP2040 |
| MIC1 | MP34DT05TR-A |
| U2 | W25Q128JV QSPI Flash |
| U3 | LD1117-3.3 V |
| J1 | USB Type-C Connector |
schematic:
pcb design:
Parts
28| Qty | Value | Footprint | References |
|---|---|---|---|
| 6 | 100nF | Capacitor_SMD:C_0603_1608Metric | C4, C6, C10, C11, C13, C15 |
| 4 | 10k | Resistor_SMD:R_0603_1608Metric | R9, R10, R11, R12 |
| 2 | 10uF | Capacitor_SMD:C_0805_2012Metric | C3, C8 |
| 2 | 12pF | Capacitor_SMD:C_0603_1608Metric | C5, C7 |
| 2 | 5.1k | Resistor_SMD:R_0603_1608Metric | R6, R7 |
| 2 | SW_Push | Button_Switch_SMD:SW_SPST_EVQP7C | SW1, SW2 |
| 1 | 12MHz | Crystal:Crystal_SMD_3215-2Pin_3.2x1.5mm | Y1 |
| 1 | 1uF | Capacitor_SMD:C_0603_1608Metric | C14 |
| 1 | 600Ω | Inductor_SMD:L_0603_1608Metric | FB1 |
| 1 | Conn_01x04 | Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_Vertical | J2 |
| 1 | LD1117S12TR_SOT223 | Package_TO_SOT_SMD:SOT-223-3_TabPin2 | U3 |
| 1 | MP34DT05TR-A | EasyEDA:MIC-SMD_5P-L3.0-W4.0-P0.85-BL | MIC1 |
| 1 | RP2040 | Package_DFN_QFN:QFN-56-1EP_7x7mm_P0.4mm_EP3.2x3.2mm | U5 |
| 1 | USBLC6-2P6 | Package_TO_SOT_SMD:SOT-666 | U1 |
| 1 | USB_C_Receptacle_USB2.0_16P | Connector_USB:USB_C_Receptacle_GCT_USB4105-xx-A_16P_TopMnt_Horizontal | J1 |
| 1 | W25Q128JVE | Package_SON:WSON-8-1EP_8x6mm_P1.27mm_EP3.4x4.3mm | U2 |
Questions
How big is the Mic PCB?
It measures 33.3 × 36.5 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Mic use?
28 parts, built around the RP2040, W25Q128JVEIQ, USBLC6-2P6 and MP34DT05TR-A. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Mic KiCad files?
From the joshitha-c/microphone repository on GitHub, at the commit this page was made from: the board is mic.kicad_pcb and its schematic mic.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Mic design in my own project?
Its repository states no licence, so its author keeps all rights: ask joshitha-c before reusing the design.
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