2 layers57 × 55.2 mm
LogicAnalyzer
gusmanb/logicanalyzer
24 channel, 100Msps logic analyzer hardware and software
10 parts5.1kGPL-3.0
2 layers50 × 29 mm
Keychain
aagu8162/Keychain-projectA mini keychain like thing will an oled display
- Size
- 50 × 29 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 10
- Nets
- 17
- Pads
- 50
- Tracks, vias
- 86, 6
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 31 Oct 2026
- Updated
- 1 Nov 2026
Overview
Keychain is an open-source printed circuit board by aagu8162, from the aagu8162/Keychain-project repository on GitHub, published under the MIT licence. It is a 2-layer board of 50 × 29 mm with 10 parts on 17 nets, routed with 86 tracks and 6 vias.
Its parts include 2 capacitors, 2 resistors, 2 connectors, 2 switches and 1 IC. It belongs with the lEDs and displays boards and the ESP32 and RISC-V boards of this library.
README
README.mdKeychain-project
This repository holds the open-source hardware and firmware design files for my Hack Club Half-Life week 4 project submission. This project was done because I have wanted to build something like this.
This week my goal was to make a keychain with an oled display which would display words. I used Kicad to build the schematics and then finally built the pcb by referring to the oled guide and by also using my experience of building the week 1 project. There was not much customizations but I arranged it in a layout which I thought would make it more compact. I used the XIAO ESP32-C3 as my microcontoller and Arduino IDE was used for the firmware. The guide had provided libraries from where I could refer code and code my controller. I also added a rechargeable battery and a slide switch to turn it on or off.
📁 Repository Structure
/pcb- KiCad schematics, layouts, and manufacturing outputs./firmware- Arduino IDE configuration code files.
Schematic of PCB
3D View
BUTTONS
Button 1: Allows to display different things as per the code
Button 2: On or off switch
BOM(Bill of Materials)
| Item | Qty | Supplier | Cost/item | Total Cost |
|---|---|---|---|---|
| XIAO ESP32 C3 | 1 | Sharvi | $6.70 | $6.70 |
| 0.96 OLED | 1 | Sharvi | $2.20 | $2.20 |
| 3.7V Lipo Rechargeable | 1 | Sharvi | $2.28 | $2.28 |
| 4.7K Ohm Resitstors | 2 | Sharvi | $0.085 | $0.17 |
| 100nF 50V Capacitor | 1 | Sharvi | $0.021 | $0.021 |
| 10uF/10000nF 25V Capacitor | 1 | Sharvi | $0.029 | $0.029 |
| Push Button | 3 | Sharvi | $0.093 | $0.279 |
| Slide Switch | 1 | Sharvi | $0.63 | $0.63 |
| 4Pin Female Berg Strip | 1 | Sharvi | $0.66 | $0.66 |
| 2Pin SMD Horizontal Connector | 1 | Sharvi | $0.41 | $0.41 |
| PCB | 1 | Seeed Studio | $9.90 | $9.90 |
| Estimated total shipping | $7.41 |
Parts
10| Qty | Value | Footprint | References |
|---|---|---|---|
| 2 | 4.7 kΩ | Resistor_SMD:R_0805_2012Metric | R1, R2 |
| 1 | 100 nF | Capacitor_SMD:C_0805_2012Metric | C1 |
| 1 | 10µF | Capacitor_SMD:C_0805_2012Metric | C2 |
| 1 | Conn_01x02_Pin | Connector_JST:JST_PH_S2B-PH-K_1x02_P2.00mm_Horizontal | J2 |
| 1 | Conn_01x04_Pin | Connector_PinSocket_2.54mm:PinSocket_1x04_P2.54mm_Vertical | J1 |
| 1 | SW_Push | Button_Switch_SMD:SW_SPST_PTS645Sx43SMTR92 | SW1 |
| 1 | SW_SPST | Button_Switch_SMD:SW_SPDT_Shouhan_MSK12C02 | SW2 |
| 1 | XIAO-ESP32-C3-SMD | esp32-c3-smd:XIAO-ESP32-C3-SMD | U1 |
The 9 most common of 10 parts.
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Questions
How big is the Keychain PCB?
It measures 50 × 29 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Keychain use?
10 parts. 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 aagu8162/Keychain-project repository on GitHub, at the commit this page was made from: the board is pcb/keychain.kicad_pcb and its schematic pcb/keychain.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 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).