

InductorSchem
Custom induction keyboard build
- Size
- 225 × 111.5 mm
- Copper layers
- 4
- Thickness
- 1.55 mm
- Parts
- 165
- Nets
- 97
- Pads
- 687
- Tracks, vias
- 679, 17
- Pours
- 4
- Routed
- Yes
- KiCad
- KiCad 6 (file 20211014)
- Created
- 5 Feb 2022
- Updated
- 15 Aug 2025
Overview
InductorSchem is an open-source printed circuit board by arcasoy, from the arcasoy/The-Inductor repository on GitHub. It is a 4-layer board of 225 × 111.5 mm with 165 parts on 97 nets, routed with 679 tracks and 17 vias.
It is built around the MCP23018-E/SP. Its parts include 99 switches, 54 diodes, 5 resistors, 5 connectors and 2 ICs. It belongs with the SAM D and SAM boards of this library.
Main components
1README
README.mdThe Inductor
- Induction charging keyboard (never plug it in to charge again!)
- My induction into PCB design and firmware
Features
- Split Keyboard
- Ergo & Ortholinear layout
- Induction charging
- Bluetooth communication
Components:
- Seeeduino Xiao BLE MCU
- MCP I/O Expander
- Kailh Choc Switches
- USB-C Header
Done:
- Charging circuitry design and validation
- Switch Selection: Kailh Choc Red
- Layout
- Small Scale (4 key) PCB design to validate hardware compatibility
In Progress:
PCB Design:
- Full Scale (reversible) PCB - SHIPPING!
Firmware:
- Interrupt feature to improve battery life
To Do:
- PCB
- Firmware
- Case design
Parts
165| Qty | Value | Footprint | References |
|---|---|---|---|
| 94 | SW_Push | Switch_Keyboard_Kailh:SW_Kailh_Choc_V1_1.00u | SW1, SW2, SW10, SW11, SW12, SW13, SW14, SW15, SW16, SW17, SW18, SW19, SW20, SW21, SW22, SW23 +78 |
| 54 | 1N4148 | Diode_THT:D_DO-35_SOD27_P7.62mm_Horizontal | D1, D2, D10, D11, D12, D13, D14, D15, D16, D17, D18, D19, D20, D21, D22, D23 +38 |
| 3 | SW_Push | Switch_Keyboard_Kailh:SW_Kailh_Choc_V1_2.00u_CUSTOMINDUCTOR | SW29, SW68, SW73 |
| 2 | 4.7k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R4, R5 |
| 2 | 5.1k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R1, R2 |
| 2 | SW_Push | Switch_Keyboard_Kailh:SW_Kailh_Choc_V1_2.00u_90deg | SW53, SW54 |
| 2 | USB4515-GF-A_REVA | USB4515-GF-A_REVA:GCT_USB4515-GF-A_REVA | J1, J5 |
| 1 | 39.0k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R3 |
| 1 | Battery | Connector_Wire:SolderWire-0.5sqmm_1x02_P4.6mm_D0.9mm_OD2.1mm | J2 |
| 1 | Induction Charger | Connector_Wire:SolderWire-0.5sqmm_1x02_P4.6mm_D0.9mm_OD2.1mm | J3 |
| 1 | MCP23018-E/SP | ul_MCP23018-E-SP:MCP23018-E&slash_SP | U3 |
| 1 | SeeeduinoXIAO | Seeeduino-XIAO:Seeeduino XIAO-MOUDLE14P-2.54-21X17.8MM | U1 |
| 1 | VOut | Connector_Wire:SolderWire-0.5sqmm_1x02_P4.6mm_D0.9mm_OD2.1mm | J4 |
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Questions
How big is the InductorSchem PCB?
It measures 225 × 111.5 mm and has 4 copper layers, 1.55 mm thick.
What parts does the InductorSchem use?
165 parts, built around the MCP23018-E/SP. 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 InductorSchem KiCad files?
From the arcasoy/The-Inductor repository on GitHub, at the commit this page was made from: the board is Electrical/InductorSchem/InductorSchem.kicad_pcb and its schematic Electrical/InductorSchem/InductorSchem.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the InductorSchem design in my own project?
Its repository states no licence, so its author keeps all rights: ask arcasoy before reusing the design.