2 layers33.6 × 29.3 mm
2 layers37.3 × 31.8 mm
KeyChain
Brammert42/EPKeychainA keychain equipped with a RP2040 and a E-ink
- Size
- 37.3 × 31.8 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 88
- Nets
- 77
- Pads
- 289
- Tracks, vias
- 558, 63
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 8.0 (file 20240108)
- Created
- 25 Jul 2024
- Updated
- 31 Mar 2026
Overview
KeyChain is an open-source printed circuit board by Brammert42, from the Brammert42/EPKeychain repository on GitHub. It is a 2-layer board of 37.3 × 31.8 mm with 88 parts on 77 nets, routed with 558 tracks and 63 vias.
It is built around the RP2040, ZD25WQ32CEIGR and XC6204B332MR, with the CL05A475MP5NRN, CL05B104KB54PNC and CL05A105KA5NQN among its other parts. Its parts include 49 capacitors, 12 resistors, 6 diodes, 4 connectors and 4 switches. It belongs with the RP2040 boards of this library.
Main components
12
RP2040
LQFN-56(7x7)12bit 133MHz 30 LQFN-56(7x7) Microcontrollers (MCU/MPU/SOC) ROHSRaspberry PiMicrocontrollers (MCU/MPU/SOC)
ZD25WQ32CEIGR
USON-8(2x3)-40℃~+85℃ 1.65V~3.6V 100,000 cycles 104MHz 10ms 20 Years 2ms 32Mbit 7uA Power-on reset、Hardware write protection、Software write protection、Write enable latch、Absolute write protection SPI USON-8(2x3) NOR FLASH ROHSZettaNOR FLASH
XC6204B332MR
SOT-23-5-40℃~+85℃@(Ta) 1 24V 2uA 3.3V 300mA 420mV@(100mA) 70dB@(1kHz) Fixed Over Current Protection、Over Temperature Protection Positive SOT-23-5 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSTECH PUBLICVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
CL05A475MP5NRN
040210V 4.7uF X5R ±20% 0402 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSSamsung Electro-MechanicsMultilayer Ceramic Capacitors MLCC - SMD/SMTCL05B104KB54PNC
0402100nF 50V X7R ±10% 0402 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSSamsung Electro-MechanicsMultilayer Ceramic Capacitors MLCC - SMD/SMTCL05A105KA5NQN
04021uF 25V X5R ±10% 0402 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSSamsung Electro-MechanicsMultilayer Ceramic Capacitors MLCC - SMD/SMT
0402WGF1002
0402-55℃~+155℃ 10kΩ 50V 62.5mW Thick Film Resistor ±1% ±100ppm/℃ 0402 Chip Resistor - Surface Mount ROHSUNI-ROYALChip Resistor - Surface Mount
B5819W SL
SOD-1231A 40V 600mV@1A 9A Independent SOD-123 Schottky Diodes ROHSJiangsu Changjing Electronics Technology (CJ)Schottky Diodes
6.0*6.0*6.0
SMD-4P,6x6mm12V 50mA 6mm 6mm 6mm Black Gull Wing No Round Button SPST Surface Mount,Vertical Without Bracket SMD-4P,6x6mm Tactile Switches ROHSBOOMELETactile Switches0402CG150J500NT
040215pF 50V C0G ±5% 0402 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSGuangdong Fenghua Advanced Tech (FH)Multilayer Ceramic Capacitors MLCC - SMD/SMT0402WGF1001
0402-55℃~+155℃ 1kΩ 50V 62.5mW Thick Film Resistor ±1% ±100ppm/℃ 0402 Chip Resistor - Surface Mount ROHSUNI-ROYALChip Resistor - Surface Mount0402WGF270J
0402-55℃~+155℃ 27Ω 50V 62.5mW Thick Film Resistor ±1% ±100ppm/℃ 0402 Chip Resistor - Surface Mount ROHSUNI-ROYALChip Resistor - Surface Mount
README
README.mdDisplayKeychain
This repository is used to track FW development for Display Keychain using a RP2040 and waveshare Display.
Manual
Next image
Holding the middle button for 4 seconds changes the image on the display to next image in the list.
Previous image
Holding the middle button and the left button (button closet to the small hole) for 4 seconds changes the image on the display to previous image in the list.
Uploading new FW
Get the FW files here: https://github.com/Brammert42/EPKeychain/tree/main/FW%20version
1: insert push pin in the hole next to the "previous" button untill you feel a "click"
2: while the push pin is inserted insert the micro USB.
3: on your PC the keychain will show up as flash drive as RPI-RP2, drag the new FW file into this
Parts
88| Qty | Value | Footprint | References |
|---|---|---|---|
| 21 | 10u | Capacitor_SMD:C_0402_1005Metric | C2, C15, C16, C29, C30, C34, C35, C36, C37, C38, C39, C40, C41, C42, C43, C44 +5 |
| 13 | 100n | Capacitor_SMD:C_0402_1005Metric | C1, C7, C17, C18, C19, C21, C23, C24, C25, C26, C27, C28, C31 |
| 13 | 1uF | Capacitor_SMD:C_0402_1005Metric | C3, C4, C5, C6, C8, C9, C10, C11, C12, C20, C22, C32, C33 |
| 4 | 10k | Resistor_SMD:R_0402_1005Metric | R1, R10, R13, R14 |
| 4 | MountingHole | MountingHole:MountingHole_2.1mm | H1, H2, H3, H4 |
| 3 | MBR0530 | Diode_SMD:D_SOD-123 | D1, D2, D3 |
| 3 | SW_Omron_B3FS | Button_Switch_SMD:SW_SPST_Omron_B3FS-100xP | SW1, SW3, SW6 |
| 2 | 15p | Capacitor_SMD:C_0402_1005Metric | C13, C14 |
| 2 | 1k | Resistor_SMD:R_0402_1005Metric | R4, R6 |
| 2 | 27 | Resistor_SMD:R_0402_1005Metric | R7, R8 |
| 2 | 47k | Resistor_SMD:R_0402_1005Metric | R9, R11 |
| 2 | AO3400A | Package_TO_SOT_SMD:SOT-23 | Q1, Q3 |
| 2 | ESD9B3.3ST5G | Diode_SMD:D_SOD-923 | D4, D5 |
| 1 | 3 | Resistor_SMD:R_0402_1005Metric | R2 |
| 1 | 68uH | Inductor_SMD:L_1210_3225Metric | L1 |
| 1 | ABM8-272-T3 | Crystal:Crystal_SMD_3225-4Pin_3.2x2.5mm | Y1 |
| 1 | AO3401A | Package_TO_SOT_SMD:SOT-23 | Q2 |
| 1 | BAT-HLD-001-THM | Battery:BatteryHolder_Multicomp_BC-2001_1x2032 | J11 |
| 1 | Conn_01x24 | Brammm:Hirose_FH12-24S-0.5SH_1x24-1MP_P0.50mm_Horizontal | J2 |
| 1 | Conn_ARM_SWD_TagConnect_TC2030 | Connector:Tag-Connect_TC2030-IDC-NL_2x03_P1.27mm_Vertical | J3 |
| 1 | DNF | Resistor_SMD:R_0402_1005Metric | R5 |
| 1 | LBAT54HT1G | Diode_SMD:D_SOD-323 | D6 |
| 1 | MCP1802x-xx02xOT | Package_TO_SOT_SMD:SOT-23-5 | U1 |
| 1 | RP2040 | Package_DFN_QFN:QFN-56-1EP_7x7mm_P0.4mm_EP3.2x3.2mm | U5 |
| 1 | SW_MEC_5E | Brammm:SW_SPST_TL3342 | SW2 |
| 1 | TestPoint | Brammm:display | TP1 |
| 1 | USB_B_Micro | Connector_USB:USB_Micro-B_Wuerth_614105150721_Vertical | J5 |
| 1 | ZD25WQ32CEIGR | Brammm:SON50P300X200X60-9N | U4 |
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Questions
How big is the KeyChain PCB?
It measures 37.3 × 31.8 mm and has 2 copper layers, 1.6 mm thick.
What parts does the KeyChain use?
88 parts, built around the RP2040, ZD25WQ32CEIGR, XC6204B332MR and CL05A475MP5NRN. 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 KeyChain KiCad files?
From the Brammert42/EPKeychain repository on GitHub, at the commit this page was made from: the board is HardwareFiles/PCBA/V3/KeyChain.kicad_pcb and its schematic HardwareFiles/PCBA/V3/BATT.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the KeyChain design in my own project?
Its repository states no licence, so its author keeps all rights: ask Brammert42 before reusing the design.