4 layers43.2 × 62 mm
USBAudioBridge
fsodari/USBAudioBridge
NXP RT1010 based USB to I2S bridge to connect to a Digilent Arty A7.
120 parts
2 layers335.7 × 101 mm
Splitkeybaord
garvita4/split-keyboardThis is a custom spli keybaord with the 1.8inch tft diaply and rotatory encoder and also with nfc based lock system with the controlable backlight .
- Size
- 335.7 × 101 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 251
- Nets
- 196
- Pads
- 877
- Tracks, vias
- 3,177, 550
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 29 Sep 2026
- Updated
- 4 Nov 2026
Overview
Splitkeybaord is an open-source printed circuit board by garvita4, from the garvita4/split-keyboard repository on GitHub. It is a 2-layer board of 335.7 × 101 mm with 251 parts on 196 nets, routed with 3,177 tracks and 550 vias.
It is built around the ESP32-S3-WROOM-1-N4R8, ME6211A33M3G-N and TP4056, with the 1N4148WS, KT-0603W and AO3400A among its other parts. Its parts include 84 diodes, 68 resistors, 50 switches, 20 capacitors and 6 ICs. It belongs with the ESP32 boards of this library.
Main components
8
ESP32-S3-WROOM-1-N4R8
SMD,25.5x18mm-103.5dBm -40℃~+65℃ 2.4GHz 20.5dBm 355mA 3V~3.6V 95mA Bluetooth5.0 ESP32-S3R8 On-board PCB Antenna UART、SPI、I2C、USB SMD,25.5x18mm WiFi Modules ROHSEspressif SystemsWiFi Modules
ME6211A33M3G-N
SOT-23-3-40℃~+150℃ 1 120mV@(100mA) 3.3V 500mA 50uVrms 60uA 6V 70dB@(1kHz) Fixed Over Current Protection、Enable、Short Circuit Protection Positive SOT-23-3 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSMICRONEVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
TP4056
ESOP-8-40℃~+85℃ 1 1A 35uA 4.2V 4V~6.5V Charging IC Lithium Battery Support Support 恒流充电、恒压充电、涓流充电、自动再充电、充电终止、可编程充电电流、软启动、欠压锁定 ESOP-8 Battery Management ROHSUMWBattery Management
1N4148WS
SOD-3231.25V@150mA 100V 150mA 1uA@75V 200mW 2A 4ns Independent SOD-323 Switching Diodes ROHSJiangsu Changjing Electronics Technology (CJ)Switching Diodes
KT-0603W
0603-40℃~+85℃ 100mW 120° 2.6V~3.1V 360mcd 5mA Discrete Diode Top-mount White Yellow Lens 0603 LED Indication - Discrete ROHSHubei KENTO ElecLED Indication - Discrete
AO3400A
SOT-23-55℃~+150℃ 1 N-channel 1.45V 1.4W 30V 48mΩ@2.5V 5.7A 50pF 630pF 75pF 7nC@10V N-Channel SOT-23 MOSFETs ROHSAlpha & Omega SemiconductorMOSFETs
TYPE-C-31-M-12
SMD-30℃~+80℃ 1 10,000 cycles 16P 20V 5A 7.35mm Female Surface Mount, Right Angle Type-C SMD USB Connectors ROHSHRO ElectronicsUSB Connectors
SMD1206P050TF/13.2
1206-40℃~+85℃ 0.8mm 1.9mm 100ms 13.2V 150mΩ 1A 3.6mm 35A 500mA 600mW 700mΩ 1206 Resettable Fuses ROHSRUILONResettable Fuses
README
Readme.mdA Split Keyboard, Built from Scratch
Overview
This is a custom spli keybaord with the 1.8inch tft diaply and rotatory encoder and also with nfc based lock system with the controlable backlight . This keyboard can be used as wired keybaord as well as the wireless keybaord with the 2 bluetooth profile
Key Features
Split Mechanical Layout
Two separate keyboard halves, each built around its own ESP32-S3 microcontroller and supporting electronics.
Each side having 21 MX switches and with the backlight.
Rotary Encoder Controls
EC11 rotary encoders provide physical controls for functions such as volume and brightness.
TFT Display
Two 1.8-inch TFT displays are included for displaying system information such as battery percentage and connectivity status. Can also play animation on idle state.
RFID Integration
RC522 readers provide the hardware for RFID card detection and card-based interactions used to unlock the keyboard or the PC depend on the firmware either use it as the keyboard lock or use it to open the pc via your nfc tag or the phone nfc
Rechargeable Power
Each half has a rechargeable 10000 mah LiPo battery witht he inbuilt BMS which power up the whole half and can provide long lasting backup on the bluetooth mode .
Per-Key Backlighting
White 0805 SMD LEDs are use to work as the backlight like professional keybaord with the intensity control uc an control the backlight intensity with the same rotatory encoder
Schematic Design
Key Switch Matrix
The switch matrix connects the mechanical switches to the microcontroller. Diodes help prevent unwanted electrical paths during simultaneous key presses.
Switches and Diodes
Mechanical switches provide individual key inputs, while 1N4148WS diodes support switch-matrix isolation.
Resistors and LEDs
Resistors support the associated circuits, while white SMD LEDs provide per-key backlighting.
Microcontroller
The ESP32-S3-WROOM-1-N4R8 acts as the main controller for each keyboard half.
Rotary Encoders
The EC11 encoders provide rotation and switch inputs for additional keyboard controls.
Display Circuit
The display connections allow the ESP32-S3 to communicate with the TFT modules.
RFID Circuit
The RC522 reader connections provide the interface for RFID card detection.
Power Management
The power circuit includes LiPo battery charging, 3.3 V regulation, MOSFET switching, and resettable overcurrent protection.
USB-C Connectivity
USB-C connectors provide the interfaces intended for charging, firmware uploading, and supported wired connections.
PCB Design
The custom schematic and PCB layout were designed in KiCad, with the boards manufactured by Zbotic. The PCB integrates the keyboard matrix, controller connections, peripheral interfaces, backlighting, and power circuitry.
CAD Design
The keyboard enclosure is modelled in Fusion 360 to accommodate the custom PCB, switches, displays, rotary encoders, and internal electronics.
Enclosure
Complete Assembly
Firmware
The firmware is implemented using the Arduino framework and PlatformIO for the ESP32-S3 microcontrollers. It enables wireless communication between the two halves of the split keyboard using ESP-NOW, while the left half acts as the primary Bluetooth HID device.
The firmware scans the 4 × 6 key matrix, detects key presses and releases, and maps them to keyboard characters. The left half sends keystrokes to the connected device over Bluetooth Low Energy (BLE), while the right half transmits key events wirelessly to the left half.
The implementation uses the BleKeyboard library for Bluetooth keyboard functionality and ESP-NOW for communication between the two halves. The current firmware provides the foundation for the keyboard's core input functionality and can be extended with additional key mappings, layers, and peripheral integrations.
Bill of Materials (BOM)
The following table lists the components required to build the REIKAI split mechanical keyboard, including specifications, quantities, estimated costs, and sourcing links.
Component Breakdown
| Category | Component | Qty | Specifications | Unit Price (INR) | Total (INR) | Unit Price (USD) | Total (USD) | Source |
|---|---|---|---|---|---|---|---|---|
| Processing & Communications | ESP32-S3-WROOM-1 | 2 | Dual-core, Wi-Fi/BLE, 16MB Flash, 8MB PSRAM | ₹569.00 | ₹1,138.00 | $6.0324 | $12.06 | Robu |
| Processing & Communications | RC522 Mini NFC Module | 2 | Mini PCB, SPI interface | ₹139.00 | ₹278.00 | $1.4736 | $2.95 | Indian Hobby Center |
| Processing & Communications | 1.8" TFT Display | 2 | SPI interface, ST7735 | ₹309.00 | ₹618.00 | $3.2759 | $6.55 | Robu |
| Inputs & Key Matrix | MX Mechanical Switches | 42 | Cherry MX2A, ₹391 per pack of 10 | ₹39.10 | ₹1,642.20 | $0.4145 | $17.41 | Meckeys |
| Inputs & Key Matrix | Switch Diodes | 42 | 1N4148WS, SOD-323 | ₹1.09 | ₹45.78 | $0.0116 | $0.49 | Sunrom |
| Inputs & Key Matrix | EC11 Rotary Encoder | 2 | 5-pin, through-hole, push button | ₹58.00 | ₹116.00 | $0.6149 | $1.23 | Robu |
| Illumination | 0805 White LEDs | 42 | SMD backlight LEDs | ₹0.58 | ₹24.36 | $0.0061 | $0.26 | KTRON |
| Illumination | AO3400A N-Channel MOSFET | 2 | SOT-23, LED PWM dimming | ₹6.00 | ₹12.00 | $0.0636 | $0.13 | Robu |
| Power & Connectivity | USB Type-C Receptacle | 4 | 16-pin SMD connector | ₹5.55 | ₹22.20 | $0.0588 | $0.24 | KTRON |
| Power & Connectivity | 10,000 mAh LiPo Battery | 2 | Single-cell, 3.7V–4.2V | ₹399.00 | ₹798.00 | $4.2301 | $8.46 | MakerBazar |
| Power & Connectivity | TP4056 IC | 2 | SOP-8, LiPo charger | ₹5.05 | ₹10.10 | $0.0535 | $0.11 | KTRON |
| Power & Connectivity | ME6211A33M3G IC | 2 | SOT-23-5, 3.3V LDO regulator | ₹8.00 | ₹16.00 | $0.0848 | $0.17 | Robu |
| Power & Connectivity | Resettable PTC Fuse | 2 | 1206, 500mA | ₹9.00 | ₹18.00 | $0.0954 | $0.19 | Robu |
| Power & Connectivity | SMD Push Switches | 4 | 3×4×2.5mm, BOOT/EN | ₹4.29 | ₹17.16 | $0.0455 | $0.18 | Robu |
| Power & Connectivity | Slide Switch | 2 | SPDT, battery disconnect | ₹2.70 | ₹5.40 | $0.0286 | $0.06 | Robu |
| Supporting Passives | 100Ω Resistor | 42 | 0805 SMD, LED current limiting | ₹0.30 | ₹12.60 | $0.0032 | $0.13 | KTRON |
| Supporting Passives | 10kΩ Resistor | 12 | 0805 SMD, pull-up/pull-down | ₹0.30 | ₹3.60 | $0.0032 | $0.04 | KTRON |
| Supporting Passives | 56kΩ Resistor | 4 | 0805 SMD, HOST_PWR_EN divider | ₹0.30 | ₹1.20 | $0.0032 | $0.01 | KTRON |
| Supporting Passives | 5.1kΩ Resistor | 4 | 0805 SMD, HOST_PWR_EN divider | ₹0.30 | ₹1.20 | $0.0032 | $0.01 | KTRON |
| Supporting Passives | 1.2kΩ Resistor | 2 | 0805 SMD, TP4056 PROG pin | ₹0.30 | ₹0.60 | $0.0032 | $0.01 | KTRON |
| Supporting Passives | 10µF Capacitor | 10 | 0805 SMD, decoupling | ₹7.98 | ₹79.80 | $0.0846 | $0.85 | KTRON |
| Supporting Passives | 1µF Capacitor | 2 | 0805 SMD, power filtering | ₹8.50 | ₹17.00 | $0.0901 | $0.18 | KTRON |
| Supporting Passives | 100nF Capacitor | 8 | 0805 SMD, noise decoupling | ₹1.00 | ₹8.00 | $0.0106 | $0.08 | KTRON |
| PCB | Custom PCB | 1 | Custom-designed PCB fabrication | ₹4,243.50 | ₹4,243.50 | $45.00 | $45.00 | Zbotic |
Cost Summary
| Description | Amount |
|---|---|
| Grand Total (INR) | ₹9,128.80 |
| Grand Total (USD) | $96.80 |
Tools & Technologies
- PCB Design: KiCad
- CAD Modelling: Fusion 360
- Firmware: Cpp, ESP-IDF, FreeRTOS
- Microcontroller: ESP32-S3
- PCB Manufacturing: Zbotic
Parts
251| Qty | Value | Footprint | References |
|---|---|---|---|
| 42 | 0805 | Resistor_SMD:R_0805_2012Metric | R1, R2, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23 +26 |
| 42 | 1N4148WS T4 | easyeda2kicad:SOD-323_L1.8-W1.3-LS2.5-RD | D1, D2, D10, D11, D12, D13, D14, D15, D16, D17, D18, D19, D20, D21, D22, D23 +26 |
| 42 | BL | easyeda2kicad:LED0603-R-RD_WHITE | LED1, LED2, LED10, LED11, LED12, LED13, LED14, LED15, LED16, LED17, LED18, LED19, LED20, LED21, LED22, LED23 +26 |
| 40 | SW_Push | Button_Switch_Keyboard:SW_Cherry_MX_1.00u_PCB | SW1, SW2, SW10, SW11, SW12, SW13, SW14, SW15, SW16, SW17, SW18, SW19, SW20, SW21, SW22, SW23 +24 |
| 12 | 10k | Resistor_SMD:R_0805_2012Metric | R43, R44, R47, R48, R55, R56, R57, R58, R59, R60, R65, R66 |
| 8 | 100n | Capacitor_SMD:C_0805_2012Metric | C7, C8, C9, C10, C15, C16, C19, C20 |
| 8 | 10u | Capacitor_SMD:C_0805_2012Metric | C1, C2, C5, C6, C11, C12, C13, C14 |
| 8 | 5.1k | Resistor_SMD:R_0805_2012Metric | R45, R46, R51, R52, R61, R62, R63, R64 |
| 4 | 56k | Resistor_SMD:R_0805_2012Metric | R67, R68, R69, R70 |
| 2 | 1.2K | Resistor_SMD:R_0805_2012Metric | R49, R50 |
| 2 | 10U | Capacitor_SMD:C_0805_2012Metric | C3, C4 |
| 2 | 1u | Capacitor_SMD:C_0805_2012Metric | C17, C18 |
| 2 | AO3400A | easyeda2kicad:SOT-23-3_L2.9-W1.3-P1.90-LS2.4-BR | Q1, Q2 |
| 2 | BATT | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J5, J6 |
| 2 | ESP32-S3-WROOM-1-N4R8 | easyeda2kicad:WIRELM-SMD_ESP32-S3-WROOM-1 | U1, U2 |
| 2 | J_LINK | easyeda2kicad:USB-C_SMD-TYPE-C-31-M-12_1 | USBC3, USBC4 |
| 2 | ME6211A33M3G-N | easyeda2kicad:SOT-23-3_L2.9-W1.6-P1.90-LS2.8-BR | U5, U6 |
| 2 | NFC2 | Connector_PinHeader_2.54mm:PinHeader_1x08_P2.54mm_Vertical | J7, J8 |
| 2 | RotaryEncoder_Switch | Rotary_Encoder:RotaryEncoder_Alps_EC11E-Switch_Vertical_H20mm | SW43, SW44 |
| 2 | SMD1206P050TF/13.2_C393935 | easyeda2kicad:F1206 | F1, F2 |
| 2 | SW_Push | Button_Switch_Keyboard:SW_Cherry_MX_1.50u_PCB | SW41, SW42 |
| 2 | SW_Wuerth_450301014042 | Button_Switch_THT:SW_Slide-03_Wuerth-WS-SLTV_10x2.5x6.4_P2.54mm | SW51, SW52 |
| 2 | TFTTT | Connector_PinHeader_2.54mm:PinHeader_1x08_P2.54mm_Vertical | J3, J4 |
| 2 | TP4056_C725790 | easyeda2kicad:ESOP-8_L4.9-W3.9-P1.27-LS6.0-BL-EP | U3, U4 |
| 2 | TYPE-C-31-M-12 | easyeda2kicad:USB-C_SMD-TYPE-C-31-M-12_1 | USBC1, USBC2 |
| 2 | VAL** | Panelization:mouse-bite-5mm-slot | mouse-bite-5mm-slot, mouse-bite-5mm-slot |
| 2 | boot | Button_Switch_SMD:SW_SPST_EVQPE1 | SW48, SW50 |
| 2 | reset | Button_Switch_SMD:SW_SPST_EVQPE1 | SW47, SW49 |
The 244 most common of 251 parts.
Questions
How big is the Splitkeybaord PCB?
It measures 335.7 × 101 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Splitkeybaord use?
251 parts, built around the ESP32-S3-WROOM-1-N4R8, ME6211A33M3G-N, TP4056 and 1N4148WS. 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 Splitkeybaord KiCad files?
From the garvita4/split-keyboard repository on GitHub, at the commit this page was made from: the board is PCB/splitkeybaord.kicad_pcb and its schematic PCB/splitkeybaord.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Splitkeybaord design in my own project?
Its repository states no licence, so its author keeps all rights: ask garvita4 before reusing the design.
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