4 layers74 × 36.3 mm
Loudcardsdevice
gelotek-com/Anki-In-Hardware
Building a physical flashcard device inspired by Anki and spaced repetition.
87 parts2
2 layers54 × 85 mm
THIS IS GOOD COPY
CaptainCookie14/wallet-mp3-playerThis project is a compact, portable MP3 player designed to fit roughly the size of a credit card. It focuses on minimal power usage, small PCB design, and simple user controls for playing music from onboard or external storage.
- Size
- 54 × 85 mm
- Copper layers
- 2
- Thickness
- 0.8 mm
- Parts
- 72
- Nets
- 74
- Pads
- 308
- Tracks, vias
- 681, 95
- Pours
- 7
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 28 Mar 2026
- Updated
- 29 Mar 2026
Overview
THIS IS GOOD COPY is an open-source printed circuit board by CaptainCookie14, from the CaptainCookie14/wallet-mp3-player repository on GitHub. It is a 2-layer board of 54 × 85 mm with 72 parts on 74 nets, routed with 681 tracks and 95 vias.
It is built around the TPA6132A2RTE, AMS1117 and PCM5102APW, with the USBLC6-2SC6 among its other parts. Its parts include 34 capacitors, 15 resistors, 6 switches, 5 ICs and 4 connectors. It belongs with the STM32 boards of this library.
Main components
4
TPA6132A2RTE
WQFN-16-EP(3x3)-40℃~+85℃ 0.02% 100dB 100dB 2-Channel 2.1mA 2.3V~5.5V 25mWx2@16Ω Automatic mute/no-noise switch、Enable/shutdown function、Digitally programmable gain WQFN-16-EP(3x3) Audio Amplifiers ROHSTexas InstrumentsAudio Amplifiers
AMS1117
1.0 A Low-Dropout Fixed RegulatorAdvanced Monolithic SystemsUncategorised
PCM5102APW
TSSOP-20-25℃~+85℃ 1.8V~3.3V 2 32 384kHz 500uA 50MHz Audio Decoder Digital filtering、Power-down mode I2S TSSOP-20 ADCs/DACs - Special Purpose ROHSTexas InstrumentsADCs/DACs - Special Purpose
USBLC6-2SC6
SOT-23-60.35pF、0.8pF 100nA 150W@8/20us 15V 2 5V 6A@8/20us 6V ESD SOT-23-6 ESD and Surge Protection (TVS/ESD) ROHSUMWESD And Surge Protection (TVS/ESD)
README
README.mdwallet-mp3-player
This project is a small, portable MP3 player, designed to be roughly the size of a credit card. This project is all about minimal power consumption, small PCB design, and ease of use for the player.
HOW TO USE IT Insert a micro SD card containing MP3 or WAV files into the device. Turn it on using the battery and play the songs using the buttons. It does not require a phone or computer to play songs. Users can play, pause, and skip songs, and also change the volume using the buttons.
Features
Plays MP3 audio files Ultra-compact PCB design (credit card sized) Button-based controls (play/pause, next, previous, volume) Supports microSD storage for music files Low power consumption for portable devices Optional output for headphones or small speakers
HOW IT WORKS:
It is composed of a microcontroller, which reads the audio files from a storage module, usually a microSD card. The microcontroller then sends the decoded audio to an amplifier for output.
The buttons are always being read by the microcontroller, which controls the state of the player, the songs being played, and the volume.
HARDWARE USED:
-Microcontroller ( STM32F411CEU6x )
- Micro SD card module
- Audio DAC module
- Small audio amplifier
- Tactile and low-profile buttons
- Lithium battery and charging circuit
- PCB designed in KiCad
WIRING/CONNECTIONS:
- Micro SD card module is connected through SPI
- Audio module is connected through I2S or analog pins
- Buttons are connected to digital GPIOs with pull-ups
- Battery is connected through power management circuit
The goal of this project is to create a fully functional, pocket-sized music player that is:
- as thin as possible (under 5mm)
- at least 5 hours of playing time
- able to fit in your wallet
- cheap as possible to make (under 80$ per unit after considering battery, case, shipping & PCB assembly)
The PCB files in this repository were prepared using the JLCPCB KiCad plugin to streamline manufacturing and assembly.
After completing the schematic and PCB layout in KiCad, the plugin was used to:
Generate production-ready Gerber files Export drill files (Excellon format) Create a complete BOM (Bill of Materials) with part numbers Generate a CPL (Pick and Place file) for SMT assembly Automatically align component footprints with JLCPCB’s supported parts library
i also added the project files and schematic files used for kiCad
Status
Currently in development / testing stage. PCB revisions and firmware improvements are ongoing and am trying to get my first prototype tested.
BOM MATERIALS LIST:
Parts
72| Qty | Value | Footprint | References |
|---|---|---|---|
| 12 | 100n | Capacitor_SMD:C_0402_1005Metric | C1, C2, C3, C12, C13, C14, C16, C18, C22, C28, C29, C33 |
| 7 | 10k | Resistor_SMD:R_0402_1005Metric | R1, R4, R5, R6, R7, R9, R10 |
| 6 | 1uf | Capacitor_SMD:C_0402_1005Metric | C6, C7, C24, C25, C30, C31 |
| 5 | 10u | Capacitor_SMD:C_0805_2012Metric | C4, C15, C17, C19, C32 |
| 5 | SW_Push | Button_Switch_SMD:SW_Push_1P1T_XKB_TS-1187A | SW2, SW3, SW4, SW5, SW6 |
| 4 | 2u2 | Capacitor_SMD:C_0402_1005Metric | C23, C26, C27, C43 |
| 4 | MountingHole | MountingHole:MountingHole_2.2mm_M2 | H1, H2, H3, H4 |
| 2 | 1.5k ohm | Resistor_SMD:R_0402_1005Metric | R2, R3 |
| 2 | 10ohm | Resistor_SMD:R_0402_1005Metric | R13, R14 |
| 2 | 10p | Capacitor_SMD:C_0402_1005Metric | C8, C9 |
| 2 | 2.2n | Capacitor_SMD:C_0402_1005Metric | C44, C45 |
| 2 | 22u | Capacitor_SMD:C_0805_2012Metric | C10, C11 |
| 2 | 450 | Resistor_SMD:R_0402_1005Metric | R11, R12 |
| 2 | 5k1 | Resistor_SMD:R_0402_1005Metric | R15, R16 |
| 2 | LED | LED_SMD:LED_0805_2012Metric | D1, D2 |
| 1 | 10n | Capacitor_SMD:C_0402_1005Metric | C5 |
| 1 | 120 ohms @ 100 mhz | Inductor_SMD:L_0603_1608Metric | FB1 |
| 1 | 16mhz | Crystal:Crystal_SMD_3225-4Pin_3.2x2.5mm | Y1 |
| 1 | AMS1117 | Package_TO_SOT_SMD:SOT-223-3_TabPin2 | U2 |
| 1 | AudioJack3 | Connector_Audio:Jack_3.5mm_CUI_SJ-3523-SMT_Horizontal | J5 |
| 1 | Conn_01x04_Pin | Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_Vertical | J1 |
| 1 | Micro_SD_Card | sd_card_socket:TF-01A | J2 |
| 1 | PCM5102A | Package_SO:TSSOP-20_4.4x6.5mm_P0.65mm | U4 |
| 1 | STM32F411CEUx | Package_DFN_QFN:QFN-48-1EP_7x7mm_P0.5mm_EP5.6x5.6mm | U1 |
| 1 | SW_SPDT | Button_Switch_SMD:SW_SPDT_PCM12 | SW1 |
| 1 | TPA6132A2RTE | Package_DFN_QFN:WQFN-16-1EP_3x3mm_P0.5mm_EP1.6x1.6mm_ThermalVias | U5 |
| 1 | USBLC6-2SC6 | Package_TO_SOT_SMD:SOT-23-6 | U3 |
| 1 | USB_C_Receptacle_USB2.0_16P | Connector_USB:USB_C_Receptacle_HCTL_HC-TYPE-C-16P-01A | J4 |
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Questions
How big is the THIS IS GOOD COPY PCB?
It measures 54 × 85 mm and has 2 copper layers, 0.8 mm thick.
What parts does the THIS IS GOOD COPY use?
72 parts, built around the TPA6132A2RTE, AMS1117, PCM5102APW and USBLC6-2SC6. 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 THIS IS GOOD COPY KiCad files?
From the CaptainCookie14/wallet-mp3-player repository on GitHub, at the commit this page was made from: the board is PCB project (kicad)/THIS IS GOOD COPY.kicad_pcb and its schematic PCB project (kicad)/THIS IS GOOD COPY.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the THIS IS GOOD COPY design in my own project?
Its repository states no licence, so its author keeps all rights: ask CaptainCookie14 before reusing the design.