4 layers80 × 50 mm
HadesNT
pms67/HadesFCS
Complete flight control system designed from scratch. Hardware designed with KiCad.
103 parts1kBSD-3-Clause
4 layers62 × 21 mm
Keysatron
fablackner/keysatronKeysatron is built around the STM32F405RGT6 ARM Cortex-M4 microcontroller, which features two independent USB OTG controllers: 1.
- Size
- 62 × 21 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 32
- Nets
- 22
- Pads
- 147
- Tracks, vias
- 282, 48
- Pours
- 2
- Routed
- Yes
- KiCad
- KiCad 5 (file 20171130)
- Created
- 28 Oct 2026
- Updated
- 28 Oct 2026
Overview
Keysatron is an open-source printed circuit board by fablackner, from the fablackner/keysatron repository on GitHub. It is a 4-layer board of 62 × 21 mm with 32 parts on 22 nets, routed with 282 tracks and 48 vias.
It is built around the STM32F405RGT6, MP2451DT-LF-Z and SRV05-4, with the B5819W among its other parts. Its parts include 14 capacitors, 7 resistors, 3 ICs, 3 diodes and 3 connectors. It belongs with the STM32 boards of this library.
Main components
4
STM32F405RGT6
LQFP-64(10x10)-40℃~+85℃ 1.8V~3.6V 12bit 12bit 168MHz 192KB 1MB 32 Bit 51 ARM Cortex-M4 Built-in FLASH LQFP-64(10x10) Microcontrollers (MCU/MPU/SOC) ROHSSTMicroelectronicsMicrocontrollers (MCU/MPU/SOC)
MP2451DT-LF-Z
SOT-23-6-40℃~+125℃ 1 130uA 2MHz 3.3V~36V 600mA 800mV~28.8V Adjustable Buck Buck Built-in No SOT-23-6 DC-DC Converters ROHSMonolithic Power SystemsDC-DC ConvertersSRV05-4
SOT-23-6L-55℃~+150℃ 15V 1pF 4A 5V 5uA 6V 80W ESD Four channels IEC 61000-4-2、IEC 61000-4-5 Unidirectional SOT-23-6L ESD and Surge Protection (TVS/ESD) ROHShongjiachengESD And Surge Protection (TVS/ESD)
B5819W
SOD-123-55℃~+125℃ 1.5A 1mA@40V 25A 40V 600mV@1A Standalone SOD-123 Schottky Diodes ROHSMDDSchottky Diodes
README
README.mdKeysatron
Keysatron is an inline USB-to-USB hardware adapter designed to intercept, transform, and remap USB HID keyboard input in real-time. By sitting transparently between your physical keyboard and your computer, it allows hardware-level key translation—such as converting German ISO (QWERTZ) keystrokes into Colemak ISO layout—without requiring any software, drivers, or administrative privileges on the host operating system.
Hardware Overview
Keysatron is built around the STM32F405RGT6 ARM Cortex-M4 microcontroller, which features two independent USB OTG controllers:
- USB OTG FS (Full-Speed): Operates as USB Host on port
USB_IN(J2) to read input reports from connected USB keyboards. - USB OTG HS (with embedded Full-Speed PHY): Operates as USB Device on port
USB_PC(J3) to emulate a USB HID keyboard to the host PC.
Specifications
| Feature | Description |
|---|---|
| Microcontroller | STM32F405RGT6 (ARM Cortex-M4 @ 168 MHz, 1 MB Flash, 192 KB SRAM) |
Input Port (USB_IN, J2) | USB Type-A Female – USB OTG FS Host (PA11 DM, PA12 DP) |
Output Port (USB_PC, J3) | USB Type-A Female / Cable – USB OTG HS Device in FS mode (PB14 DM, PB15 DP) |
| Power Supply | MP2451DT step-down buck converter (5 V VBUS to 3.3 V core rail) |
| Oscillator | 16 MHz external crystal (HSE) |
| ESD Protection | SRV05-4 transient voltage suppressors on USB data lines |
| Status LEDs | Red LED (D1): Power indicator (3.3 V rail)Green LED ( D3): Status / activity indicator (GPIO PA0) |
| Debug Header | 5-pin 2.54 mm SWD header (J1) |
SWD Header Pinout (J1)
The board provides a 5-pin single-row header (J1, 2.54 mm pitch) for programming and debugging via SWD:
[ 1: GND ] [ 2: NRST ] [ 3: CLK ] [ 4: IO ] [ 5: 3.3V ]| Pin | Label | STM32 Pin | Function |
|---|---|---|---|
| 1 | GND | VSS (Pins 12, 18, 60, 63) | Ground |
| 2 | NRST | NRST (Pin 7) | Active-low system reset |
| 3 | CLK | PA14 (Pin 49) | SWD Clock (SWCLK) |
| 4 | IO | PA13 (Pin 46) | SWD Data (SWDIO) |
| 5 | 3.3V | VDD (Pins 1, 13, 19, 32, 48, 64) | 3.3 V Power rail |
Connecting to an ST-LINK / Nucleo Debugger
When using the built-in ST-LINK/V2-1 on an STM32 Nucleo-64 board (CN4 header):
[!IMPORTANT] Remove the two jumpers on
CN2on the Nucleo board to disconnect the debugger from the onboard microcontroller and direct SWD lines to headerCN4.Note that
CN4Pin 1 (VDD_TARGET) is a voltage-sensing line and does not power the target. Power Keysatron via USB or connect3V3from the Nucleo power header (CN6Pin 4) to KeysatronJ1Pin 5.
Wiring between Nucleo CN4 and Keysatron J1:
| Nucleo CN4 Pin | Nucleo Function | Wire to Keysatron J1 Pin | Keysatron Function |
|---|---|---|---|
| Pin 1 | VDD_TARGET | Pin 5 | 3.3V |
| Pin 2 | SWCLK | Pin 3 | CLK |
| Pin 3 | GND | Pin 1 | GND |
| Pin 4 | SWDIO | Pin 4 | IO |
| Pin 5 | NRST | Pin 2 | NRST |
Repository Contents
keysatron.kicad_pcb– KiCad PCB layout (4-layer board)keysatron.sch– KiCad schematickeysatron.pro– KiCad project configurationkeysatron.csv– Bill of Materials (BOM) with LCSC component part numbersassembly/– Pick-and-place component position files (keysatron-all-pos.csv) and BOM (keysatron_bom.csv) for automated assemblygerber/– Gerber fabrication files and drill files ready for PCB manufacturing (keysatron_gerber.zip)
Firmware
The companion firmware for this board is maintained in the keysatron-firmware repository.
Parts
32| Qty | Value | Footprint | References |
|---|---|---|---|
| 5 | 100n | Capacitor_SMD:C_0402_1005Metric | C6, C7, C8, C9, C10 |
| 2 | 12p | Capacitor_SMD:C_0402_1005Metric | C13, C14 |
| 2 | 1k | Resistor_SMD:R_0603_1608Metric | R5, R6 |
| 2 | 2u2 | Capacitor_SMD:C_0603_1608Metric | C11, C12 |
| 2 | USB | Connector_USB:USB_A_Molex_67643_Horizontal | J2, J3 |
| 1 | 100k | Resistor_SMD:R_0603_1608Metric | R1 |
| 1 | 100n | Capacitor_SMD:C_0603_1608Metric | C1 |
| 1 | 10u | Capacitor_SMD:C_1206_3216Metric | C4 |
| 1 | 120k | Resistor_SMD:R_0603_1608Metric | R2 |
| 1 | 16Mhz | Crystal:Crystal_SMD_3225-4Pin_3.2x2.5mm | Y1 |
| 1 | 2.2u | Inductor_SMD:L_Sunlord_MWSA0518_5.4x5.2mm | L1 |
| 1 | 33p | Capacitor_SMD:C_0603_1608Metric | C3 |
| 1 | 39k | Resistor_SMD:R_0603_1608Metric | R4 |
| 1 | 47 | Resistor_SMD:R_0402_1005Metric | R7 |
| 1 | 4u7 | Capacitor_SMD:C_1206_3216Metric | C2 |
| 1 | 4u7 | Capacitor_SMD:C_0603_1608Metric | C5 |
| 1 | 68k | Resistor_SMD:R_0603_1608Metric | R3 |
| 1 | B5819W | Diode_SMD:D_SOD-123 | D2 |
| 1 | GREEN | Diode_SMD:D_0603_1608Metric | D3 |
| 1 | MP2451DT-LF-Z | Package_TO_SOT_SMD:SOT-23-6 | U1 |
| 1 | RED | Diode_SMD:D_0603_1608Metric | D1 |
| 1 | SRV05-4 | Package_TO_SOT_SMD:SOT-23-6 | U2 |
| 1 | STM32F405RGT6 | Package_QFP:LQFP-64_10x10mm_P0.5mm | U3 |
| 1 | SWD | Connector_PinHeader_2.54mm:PinHeader_1x05_P2.54mm_Vertical | J1 |
Questions
How big is the Keysatron PCB?
It measures 62 × 21 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Keysatron use?
32 parts, built around the STM32F405RGT6, MP2451DT-LF-Z, SRV05-4 and B5819W. 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 Keysatron KiCad files?
From the fablackner/keysatron repository on GitHub, at the commit this page was made from: the board is keysatron.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Can I use the Keysatron design in my own project?
Its repository states no licence, so its author keeps all rights: ask fablackner before reusing the design.
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