2 layers111.5 × 94.4 mm
2 layers98.8 × 94 mm
26proto
old-bridge/pre-26thDensofor prototyping 26denso
- Size
- 98.8 × 94 mm
- Copper layers
- 2
- Thickness
- 1 mm
- Parts
- 80
- Nets
- 146
- Pads
- 370
- Tracks, vias
- 649, 171
- Pours
- 221
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 24 Oct 2025
- Updated
- 24 Feb 2026
Overview
26proto is an open-source printed circuit board by old-bridge, from the old-bridge/pre-26thDenso repository on GitHub. It is a 2-layer board of 98.8 × 94 mm with 80 parts on 146 nets, routed with 649 tracks and 171 vias.
It is built around the MAX3485ED, DS3231MZ/V+ and BNO085. Its parts include 32 resistors, 13 connectors, 8 ICs, 4 diodes and 3 capacitors. It belongs with the ESP32 and RISC-V boards of this library.
Main components
3
MAX3485ED
SOP-8-40℃~+85℃ 1 1 10Mbps 1mA 3.135V~3.465V 32 Half-Duplex Transceiver ±8kV SOP-8 RS-485 / RS-422 ICs ROHSHTC Korea TAEJIN TechRS-485 / RS-422 ICs
DS3231MZ/V+
SOIC-8-40℃~+85℃ 2.3V~5.5V Built-in I2C Temperature compensation、Backup power management and battery charging、Alarm function、Locking and tamper-proof、Periodic interrupt output SOIC-8 Real Time Clocks ROHSMaxim Integrated (Analog Devices)Real Time Clocks
BNO085
LGA-28(3.8x5.2)1.65V~3.6V 12bit、16bit IMU (accelerometer + gyroscope) SPI、I2C、UART X,Y,Z X,Y,Z ±2000dps ±8g LGA-28(3.8x5.2) Accelerometers ROHSCEVAAccelerometers
README
README.mdpre-26thDenso
for prototyping 26denso
Parts
80| Qty | Value | Footprint | References |
|---|---|---|---|
| 7 | 10k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R1, R2, R3, R9, R13, R18, R30 |
| 6 | 220k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R24, R28, R33, R34, R35, R36 |
| 6 | 2k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R6, R7, R8, R11, R12, R14 |
| 3 | 100 | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R22, R23, R31 |
| 3 | Conn_01x02 | Connector_JST:JST_PH_S2B-PH-SM4-TB_1x02-1MP_P2.00mm_Horizontal | Batt1, Batt2, Batt4 |
| 3 | LED | LED_SMD:LED_0603_1608Metric_Pad1.05x0.95mm_HandSolder | D1, D2, D4 |
| 3 | MAX3485 | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U2, U4, U8 |
| 2 | 120 | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R5, R32 |
| 2 | 3.3k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R10, R20 |
| 2 | 47uF | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C2, C3 |
| 1 | 0.1uF | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C1 |
| 1 | 100k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R29 |
| 1 | 2 | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R17 |
| 1 | 20k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R25 |
| 1 | 330 | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R26 |
| 1 | 3k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R27 |
| 1 | 5051104096 | footprints:CON_5051104096_MOL | J1 |
| 1 | 680 | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R4 |
| 1 | Adafruit DPS310 | Connector_PinHeader_2.54mm:PinHeader_1x07_P2.54mm_Vertical | DPS311 |
| 1 | AoA | Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Horizontal | AS5603 |
| 1 | AoS | Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Vertical | AS5602 |
| 1 | BNO085 | footprints:MODULE_4754_without_holes | J9 |
| 1 | Conn_01x03 encoder_direct | Connector_JST:JST_PH_B3B-PH-K_1x03_P2.00mm_Vertical | J6 |
| 1 | Conn_01x03 servo | Connector_JST:JST_PH_B3B-PH-K_1x03_P2.00mm_Vertical | J4 |
| 1 | Conn_01x03 speaker | Connector_JST:JST_PH_S3B-PH-K_1x03_P2.00mm_Horizontal | J13 |
| 1 | Conn_01x04 | Connector_JST:JST_XH_S4B-XH-SM4-TB_1x04-1MP_P2.50mm_Horizontal | J10 |
| 1 | D | Diode_SMD:Nexperia_CFP3_SOD-123W | D5 |
| 1 | DS3231MZ | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U6 |
| 1 | MOUDLE-SEEEDUINO-XIAO-ESP32C3_TFT | footprints:XIAO-ESP32C3-SMD | U1 |
| 1 | MOUDLE-SEEEDUINO-XIAO-ESP32C3_airdata | footprints:XIAO-ESP32C3-SMD | U9 |
| 1 | MOUDLE-SEEEDUINO-XIAO-ESP32C3_logger | footprints:XIAO-ESP32C3-SMD | U5 |
| 1 | MOUDLE-SEEEDUINO-XIAO-ESP32C3_pot | footprints:XIAO-ESP32C3-SMD | U11 |
| 1 | MS621 | Battery:BatteryHolder_Seiko_MS621F | BT2 |
| 1 | Micro_SD_Card | Connector_Card:microSD_HC_Hirose_DM3AT-SF-PEJM5 | J2 |
| 1 | NPN | Package_TO_SOT_SMD:SOT-23 | Q3 |
| 1 | RE12A | Connector_JST:JST_XH_S4B-XH-SM4-TB_1x04-1MP_P2.50mm_Horizontal | J11 |
| 1 | RS485_TFT | Connector_JST:JST_XH_S4B-XH-SM4-TB_1x04-1MP_P2.50mm_Horizontal | J5 |
| 1 | RS485_airdata | Connector_JST:JST_XH_S4B-XH-SM4-TB_1x04-1MP_P2.50mm_Horizontal | J12 |
| 1 | RS485_logger | Connector_JST:JST_XH_S4B-XH-SM4-TB_1x04-1MP_P2.50mm_Horizontal | J8 |
| 1 | RS485_logger_2 | Connector_JST:JST_XH_S4B-XH-SM4-TB_1x04-1MP_P2.50mm_Horizontal | J7 |
| 1 | SW_DIP_x01 | footprints:CLSB12A02T | SW1 |
| 1 | SolderJumper_2_Open | Jumper:SolderJumper-2_P1.3mm_Open_TrianglePad1.0x1.5mm | JP1 |
| 1 | URM37 | Connector_JST:JST_XH_S4B-XH-SM4-TB_1x04-1MP_P2.50mm_Horizontal | J3 |
The 70 most common of 80 parts.
Questions
How big is the 26proto PCB?
It measures 98.8 × 94 mm and has 2 copper layers, 1 mm thick.
What parts does the 26proto use?
80 parts, built around the MAX3485ED, DS3231MZ/V+ and BNO085. 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 26proto KiCad files?
From the old-bridge/pre-26thDenso repository on GitHub, at the commit this page was made from: the board is Kicad/boards/26proto.kicad_pcb and its schematic Kicad/boards/26proto.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the 26proto design in my own project?
Its repository states no licence, so its author keeps all rights: ask old-bridge before reusing the design.
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