2 layers100 × 80 mm
2 layers100 × 65.8 mm
KeychainProj
antelliJ/KeychainPCBCreating a keychain PCB
- Size
- 100 × 65.8 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 34
- Nets
- 38
- Pads
- 125
- Tracks, vias
- 316, 41
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 6 Oct 2026
- Updated
- 1 Nov 2026
Overview
KeychainProj is an open-source printed circuit board by antelliJ, from the antelliJ/KeychainPCB repository on GitHub, published under the MIT licence. It is a 2-layer board of 100 × 65.8 mm with 34 parts on 38 nets, routed with 316 tracks and 41 vias.
It is built around the AMS1117CD-3.3 and LIS3DH. Its parts include 12 resistors, 9 diodes, 4 capacitors, 3 ICs and 2 connectors. It belongs with the RISC-V boards of this library.
Main components
2
AMS1117CD-3.3
TO-252-40℃~+125℃ 0.003%Vout 1 1.1V@(800mA) 15V 1A 3.3V 5mA 72dB@(120Hz) Fixed Over Current Protection、Short Circuit Protection、Thermal shutdown Positive TO-252 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSAdvanced Monolithic SystemsVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
LIS3DH
LGA-16(3x3)-40℃~+85℃ 1.71V~3.6V 16bit 500nA Accelerometer Motion event detection SPI、I2C X,Y,Z ±16g LGA-16(3x3) Accelerometers ROHSSTMicroelectronicsAccelerometers
README
README.mdKeychain
Creating a keychain PCB badge
Purpose
This is a personalized PCB that aims to be carried around on a keychain, a fun PCB badge similar to the ones at opensauce. I hope this could be an interesting way to introduce myself in an interactive manner if I'm at any tech conferences or the like.
Usage and Info
Uses either a CR2032 or USB-C to power a CH32V003 MCU, toggled between using a 2 way switch.
a LIS331HH communicates to the board to activate the LED's based on the motion associated.
Programmable input is available through the headers.
The back silkscreen plugs my github account through a link and a QR code
The front silkscreens include some random things I thought would be interesting, like a ruler and fun hints to get people interested in what the board can actually do
File structure
\PCB\ includes files relevant for the pcb and manufacturing.
\PCB\production are the files used for PCB manufacturing
\Code\ is intended for all the code, which is basically empty at the moment. Eventually it will have the custom firmware.
Features (mostly planned)
Shake to wake, various taps can cycle through the different animations. One of which that would show a morse code representation of my name, among other small animations with the leds.
Bill of Materials
A nicely formatted excel sheet is provided at \PCB\production\Keychain-Bom.xlsx
The below is just a static version of that...
| Designator | Footprint | Quantity | Value | JLCPCB Part # | MPN |
|---|---|---|---|---|---|
| BT1 | BatteryHolder_Keystone_1058_1x2032 | 1 | Battery_Cell | ||
| BZ1 | Buzzer_12x9.5RM7.6 | 1 | Piezo buzzer (passive) | C76871 | PS1240P02BT |
| C1, C3 | 0805 | 2 | 100nF | C49678 | CC0805KRX7R9BB104 |
| C2, C4 | 0805 | 2 | 10uF | C15850 | CL21A106KAYNNNE |
| D1, D10, D3, D4, D5, D6, D8, D9 | 0805 | 8 | Red LED | C84256 | NCD0805R1 |
| D2 | LED_RGB_1210 | 1 | LED_RABG | C375572 | E6C1209RGBC3UDA |
| J1 | PinHeader_1x04_P2.54mm_Vertical | 1 | Conn_01x04_Pin | C52016392 | HX PH254-01-04-Z-L11.5 straight pin header |
| J2 | USB_C_Receptacle_GCT_USB4085 | 1 | USB_C_Receptacle_PowerOnly_6P | C668623 | TYPE-C 6P(073) |
| R1, R2, R3, R4 | 0805 | 4 | 100 | C17408 | 0805W8F1000T5E |
| R10, R11 | 0805 | 2 | 5k1 | C27834 | 0805W8F5101T5E |
| R12, R8, R9 | 0805 | 3 | 4k7 | C17673 | 0805W8F4701T5E |
| R7 | 0805 | 1 | 330 (RK led) | C17437 | 0805W8F1200T5E |
| SW1 | SW-SMD_MST-12D18G4-SPDT-SLIDE-SWITCH | 1 | MST-12D18G4 SPDT SLIDE SWITCH | C49023767 | MST-12D18G4 SPDT Slide Switch |
| U1 | TO-252-3_TabPin2 | 1 | AMS1117CD-3.3 | C6186 | AMS1117-3.3 |
| U2 | LGA-16_3x3mm_P0.5mm_LayoutBorder3x5y | 1 | LIS3DH | C15134 | LIS3DHTR |
| U4 | TSSOP-20_4.4x6.5mm_P0.65mm | 1 | CH32V003FxPx | C5187096 | CH32V003F4P6 |
** You may notice that r5 and r6 are missing, I included them in the schematic for the blue and green LEDs in the center RGB LED, but I don't think there is enough power for it to make it worth it? If anything it would just reduce the brightness from whatever it already is. Those pads should just be wired together if using the gerber files as is.
References
A lot of things were picked up on the way of creating this project, with it being my first proper PCB
used Table to Markdown to make the above BOM in the readme
Parts
34| Qty | Value | Footprint | References |
|---|---|---|---|
| 8 | LED | LED_SMD:LED_0805_2012Metric | D1, D3, D4, D5, D6, D8, D9, D10 |
| 4 | 100 | Resistor_SMD:R_0805_2012Metric | R1, R2, R3, R4 |
| 3 | 4k7 | Resistor_SMD:R_0805_2012Metric | R8, R9, R12 |
| 2 | 0 | Resistor_SMD:R_0805_2012Metric | R5, R6 |
| 2 | 100nF | Capacitor_SMD:C_0805_2012Metric | C1, C3 |
| 2 | 10uF | Capacitor_SMD:C_0805_2012Metric | C2, C4 |
| 2 | 5k1 | Resistor_SMD:R_0805_2012Metric | R10, R11 |
| 1 | 330 | Resistor_SMD:R_0805_2012Metric | R7 |
| 1 | AMS1117CD-3.3 | Package_TO_SOT_SMD:TO-252-3_TabPin2 | U1 |
| 1 | Battery_Cell | Battery:BatteryHolder_Keystone_1058_1x2032 | BT1 |
| 1 | Buzzer | Buzzer_Beeper:Buzzer_12x9.5RM7.6 | BZ1 |
| 1 | CH32V003FxPx | Package_SO:TSSOP-20_4.4x6.5mm_P0.65mm | U4 |
| 1 | Conn_01x04_Pin | Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_Vertical | J1 |
| 1 | LED_RABG | LED_SMD:LED_RGB_1210 | D2 |
| 1 | LIS3DH | ModuleLibrary:LIS3DH_Aliexpress_Module | U2 |
| 1 | MST-12D18G4 SPDT SLIDE SWITCH | Newsymbols:SW-SMD_MST-12D18G4-SPDT-SLIDE-SWITCH | SW2 |
| 1 | MountingHole | MountingHole:MountingHole_3mm | H1 |
| 1 | USB_C_Receptacle_PowerOnly_6P | Connector_USB:USB_C_Receptacle_GCT_USB4085 | J2 |
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Questions
How big is the KeychainProj PCB?
It measures 100 × 65.8 mm and has 2 copper layers, 1.6 mm thick.
What parts does the KeychainProj use?
34 parts, built around the AMS1117CD-3.3 and LIS3DH. 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 KeychainProj KiCad files?
From the antelliJ/KeychainPCB repository on GitHub, at the commit this page was made from: the board is PCB/keychainProj.kicad_pcb and its schematic PCB/keychainProj.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the KeychainProj design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).