8 layers42.2 × 67.2 mm
OBC PCB
timohueser/OpenBikeComputer
Open source Bikecomputer with a focus on exploration and adventure.
186 parts11GPL-3.0
2 layers29 × 7.7 mm
USB Flex
timohueser/OpenBikeComputer11Open source Bikecomputer with a focus on exploration and adventure.
- Size
- 29 × 7.7 mm
- Copper layers
- 2
- Thickness
- 0.11 mm
- Parts
- 2
- Nets
- 6
- Pads
- 18
- Tracks, vias
- 0, 0
- Pours
- 2
- Routed
- Not yet
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 16 Jun 2026
- Updated
- 8 Nov 2026
Overview
USB Flex is an open-source printed circuit board by timohueser, from the timohueser/OpenBikeComputer repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 29 × 7.7 mm with 2 parts on 6 nets.
README
hardware/projects/OBC_PCB/README.mdOBC main board
Open OBC_PCB.kicad_pro in KiCad 10. Keep the project library tables with the files.
Run electrical checks from this directory:
kicad-cli sch erc --format json -o /tmp/obc-erc.json OBC_PCB.kicad_sch
kicad-cli pcb drc --schematic-parity --format json -o /tmp/obc-drc.json OBC_PCB.kicad_pcbBoard GPIO map
This table describes the main PCB. The firmware README
describes the development kit. Port the firmware pin assignments before running it on this board.
LCD_*_MCU is the net between U6 and its source resistor; LCD_* continues to J1.
| Device | Pad | GPIO | Signal | Connection |
|---|---|---|---|---|
| U6 | 1 | P2.01 | SD_CLK | R9, 33 Ω at U6; fixed SD pin |
| U6 | 2 | P2.02 | SD_D0 | Fixed SD pin |
| U6 | 3 | P2.03 | SD_D2 | Fixed SD pin |
| U6 | 4 | P2.04 | SD_D1 | Fixed SD pin |
| U6 | 5 | P2.05 | SD_CMD | Fixed SD pin |
| U6 | 7 | P1.29 | COM_SOURCE | |
| U6 | 8 | P1.30 | LCD_R0 | R69, 100 Ω at U6 |
| U6 | 9 | P1.31 | LCD_R1 | R70, 100 Ω at U6 |
| U6 | 10 | P1.00 | BUZZER_PWM | |
| U6 | 11 | P1.01 | LCD_GSP | R77, 220 Ω at U6 |
| U6 | 12 | P1.02 | LCD_GEN | R78, 220 Ω at U6 |
| U6 | 13 | P1.03 | LCD_BSP | R80, 220 Ω at U6 |
| U6 | 14 | P1.04 | LCD_GCK | R76, 220 Ω at U6 |
| U6 | 15 | P1.05 | LCD_BCK | R75, 100 Ω at U6 |
| U6 | 16 | P1.06 | LCD_G0 | R71, 100 Ω at U6 |
| U6 | 22 | P1.07 | LCD_G1 | R72, 100 Ω at U6 |
| U6 | 23 | P1.08 | LCD_B0 | R73, 100 Ω at U6 |
| U6 | 24 | P1.09 | LCD_B1 | R74, 100 Ω at U6 |
| U6 | 25 | P0.03 | GPS_TXD | UARTE30 RX (module TX) |
| U6 | 26 | P0.04 | BTN_SELECT | GPIO SENSE wake |
| U6 | 27 | P0.06 | BTN_NEXT | GPIO SENSE wake |
| U6 | 28 | P0.07 | BTN_BACK | GPIO SENSE wake |
| U6 | 29 | P0.08 | PMIC_INT | |
| U6 | 30 | P0.09 | GPS_RXD | UARTE30 TX (module RX) |
| U6 | 39 | P1.15 | BTN_PREV | GPIO SENSE wake |
| U6 | 40 | P1.16 | SDA | TWIM22 data |
| U6 | 41 | P1.18 | SCL | TWIM22 clock pin |
| U6 | 47 | P1.19 | ACC_INT1 | GPIO SENSE wake |
| U6 | 50 | P1.24 | LCD_INTB | R79, 220 Ω at U6 |
| U6 | 52 | P2.00 | SD_D3 | Fixed SD pin |
| U2 | 7 | GPIO0 | DISP_5V_EN | |
| U2 | 8 | GPIO1 | PMIC_INT | |
| U2 | 9 | GPIO2 | COM_EN | |
| U2 | 10 | GPIO3 | LOUD | |
| U2 | 11 | GPIO4 | DISP_DISCHARGE |
Use standard drive for the LCD outputs. Disable NFC through NFCT.PADCONFIG before
using GSP and GEN. Keep both low during reset. Set SCL and SDA on the same port.
Configure the crystal load capacitors and the internal DC/DC converter before use.
Program the bootloader through J5 before fitting the display.
For the LCD, measure 10–90% rise and fall times at J1. Target 25 ns or less; the panel limit is 50 ns. The resistor values are initial values for board testing. Check the image and GNSS reception while the display refreshes.
See Nordic's port capabilities, clock-pin rules and GPIO electrical specification.
Parts
2| Qty | Value | Footprint | References |
|---|---|---|---|
| 1 | FH12 CONTACT FINGERS | obc:FPC_12_P0.5_FH12_Tail | J2 |
| 1 | FROM USB DAUGHTERBOARD | obc:USB_Flex_Solder_6 | J1 |
Questions
How big is the USB Flex PCB?
It measures 29 × 7.7 mm and has 2 copper layers, 0.11 mm thick.
What parts does the USB Flex use?
2 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 USB Flex KiCad files?
From the timohueser/OpenBikeComputer repository on GitHub, at the commit this page was made from: the board is hardware/projects/USB_Flex/USB_Flex.kicad_pcb and its schematic hardware/projects/OBC_Fit_Test/OBC_Fit_Test.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the USB Flex design in my own project?
Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
More from timohueser/OpenBikeComputer
2- 2 layers24 × 8.7 mm
USB Baseboard
timohueser/OpenBikeComputer
Open source Bikecomputer with a focus on exploration and adventure.
5 parts11GPL-3.0
Similar boards
- 2 layers37 × 19 mm
Passive rpi hub75-adapter
hzeller/rpi-rgb-led-matrix
Controlling up to three chains of 64x64, 32x32, 16x32 or similar RGB LED displays using Raspberry Pi GPIO
2 parts4.4kGPL-2.0 - 2 layers33 × 19 mm
- 2 layers
Diode template
adamws/kicad-kbplacer
KiCad plugin for automatic keyboard's key placement and routing
2 parts547GPL-3.0 - 2 layers20.3 × 15.2 mm
L0 button
Luos-io/luos_engine
Open-source and real-time orchestrator for cyber-physical-systems, to easily design, test and deploy embedded applications and digital twins.
2 parts546MIT - 2 layers35.1 × 46.8 mm
SDEX2M2 Breakout Board
NVNTLabs/switch2-SDEX2M2
Micro SD Express to M.2 NVME Adapter for Nintendo Switch 2
2 parts542GPL-3.0 - 2 layers59.3 × 36.6 mm
ExpansionBoardTemplate
BlueSCSI/BlueSCSI-v2
BlueSCSI v2/Ultra - an open source, open hardware, SCSI emulator using the Pi Pico PR2040 and Pico 2 RP2350
2 parts459GPL-3.0 - 2 layers
Alpha.9mm.wire
ohmtech-rdi/eurorack-blocks
Software to Hardware Prototyping for Eurorack using C++, Max/Gen~ or Faust
2 parts410 - 2 layers26.7 × 64 mm
