2 layers60 × 31 mm
Usb bridge
Tai-Min/Robo-Bus
Modular series of MCUs and hardware boards designed for robotics, providing a unified bus system for seamless and reliable communication between robotic components
61 parts
2 layers54 × 69 mm
Pico expansion board
Tai-Min/Robo-BusModular series of MCUs and hardware boards designed for robotics, providing a unified bus system for seamless and reliable communication between robotic components
- Size
- 54 × 69 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 64
- Nets
- 98
- Pads
- 306
- Tracks, vias
- 624, 250
- Pours
- 10
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 9 Nov 2025
- Updated
- 5 Nov 2026
Overview
Pico expansion board is an open-source printed circuit board by Tai-Min, from the Tai-Min/Robo-Bus repository on GitHub. It is a 2-layer board of 54 × 69 mm with 64 parts on 98 nets, routed with 624 tracks and 250 vias.
It is built around the MAX3485ED, TJA1051T/3/1 and 74HC04D, with the 74HC165D, BSMD0603C-0500T and CDSOT23-T24CAN among its other parts. Its parts include 26 resistors, 11 capacitors, 8 diodes, 5 ICs and 2 connectors. It belongs with the RP2040 boards of this library.
Main components
9
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 ICsTJA1051T/3/1
-- CAN Transceivers ROHSNXP SemiconductorsCAN Transceivers
74HC04D
SOP-14-40℃~+125℃ 1 1.5V~4.2V 1.9V、3.7V、5.2V 100mV、400mV、400mV 14ns@6V,50pF 2V~6V 2uA 5.2mA 5.2mA 500mV~1.8V 6 74HC SOIC-14 Inverters ROHSNexperiaInverters
74HC165D
SO-16-40℃~+125℃ 1 28ns@6V,50pF 2V~6V 35MHz 500mW 74HC 8 Parallel or Serial to Serial SOIC-16 Shift Registers ROHSNexperiaShift Registers
BSMD0603C-0500T
0603Disposable FusesBHFUSE
CDSOT23-T24CAN
SOT-2317pF 2 24V 250W@8/20us 32V 5.5A@8/20us 50V 80nA Bidirectional IEC 61000-4-2、IEC 61000-4-5、IEC 61000-4-4 SOT-23 ESD and Surge Protection (TVS/ESD) ROHSTECH PUBLICESD And Surge Protection (TVS/ESD)DMG2305UX-7
SOT-23-55℃~+150℃ 1 P-Channel 1.4W 10.2nC@4.5V 20V 52mΩ@4.5V、100mΩ@2.5V 5A 77pF 808pF 85pF 900mV P-Channel SOT-23 MOSFETs ROHSDiodes IncorporatedMOSFETs
DSHP08TSGER
SMD,P=1.27mm-30℃~+85℃ 1.27mm 24V 25mA 3,000 Cycles 8 Black SPST SMD,P=1.27mm DIP Switches ROHSkangshenDIP SwitchesSM712-02HTG
SOT-23ESD And Surge Protection (TVS/ESD)DOWO
README
README.mdRobo-Bus
Modular series of MCUs and hardware boards designed for robotics, providing a unified bus system for seamless and reliable communication between robotic components
Parts
64| Qty | Value | Footprint | References |
|---|---|---|---|
| 14 | 10K | Resistor_SMD:R_0603_1608Metric | R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R21, R22, R23 |
| 6 | 100n | Capacitor_SMD:C_0603_1608Metric | C1, C2, C3, C4, C6, C10 |
| 5 | 1K | Resistor_SMD:R_0603_1608Metric | R1, R2, R3, R4, R5 |
| 5 | yellow | LED_SMD:LED_0603_1608Metric | D1, D2, D3, D4, D5 |
| 4 | 0R | Resistor_SMD:R_0603_1608Metric | R17, R18, R19, R20 |
| 4 | MountingHole_Pad | MountingHole:MountingHole_3.2mm_M3_Pad_Via | H1, H2, H3, H4 |
| 3 | 22u | Capacitor_SMD:C_1812_4532Metric | C5, C7, C9 |
| 1 | 191K | Resistor_SMD:R_0603_1608Metric | R25 |
| 1 | 22n | Capacitor_SMD:C_0603_1608Metric | C11 |
| 1 | 25V | Diode_SMD:D_SOD-123 | D9 |
| 1 | 300p | Capacitor_SMD:C_0603_1608Metric | C8 |
| 1 | 49.9K | Resistor_SMD:R_0603_1608Metric | R26 |
| 1 | 6.8u | Inductor_SMD:L_APV_ANR4010 | L1 |
| 1 | 74HC04 | Package_SO:TSSOP-14_4.4x5mm_P0.65mm | U1 |
| 1 | 74HC165 | Package_SO:TSSOP-16_4.4x5mm_P0.65mm | U2 |
| 1 | 90.9K | Resistor_SMD:R_0603_1608Metric | R24 |
| 1 | ADDR_EN | Connector_PinHeader_2.54mm:PinHeader_2x03_P2.54mm_Vertical | J1 |
| 1 | BSMD0603C-0500T | Fuse:Fuse_0603_1608Metric | F2 |
| 1 | CDSOT23-T24CAN | Package_TO_SOT_SMD:SOT-23 | D6 |
| 1 | DE9 | Connector_Dsub:DSUB-9_Pins_Horizontal_P2.77x2.84mm_EdgePinOffset7.70mm_Housed_MountingHolesOffset9.12mm | J2 |
| 1 | DMG2305UX-7 | Package_TO_SOT_SMD:SC-59 | Q1 |
| 1 | DSHP08TSGER | Button_Switch_SMD:SW_DIP_SPSTx08_Slide_KingTek_DSHP08TS_W7.62mm_P1.27mm | SW1 |
| 1 | LOGO | symbols:robo-bus-qr-small | G*** |
| 1 | MAX3485E | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U4 |
| 1 | MP2338 | Package_TO_SOT_SMD:SOT-583-8 | U5 |
| 1 | OSHW-Logo2_7.3x6mm_SilkScreen | Symbol:OSHW-Logo2_7.3x6mm_SilkScreen | osh |
| 1 | RaspberryPi_Pico | Module:RaspberryPi_Pico_Common_Unspecified | A1 |
| 1 | SM712-02HTG | Package_TO_SOT_SMD:SOT-23 | D7 |
| 1 | TJA1051T-3 | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U3 |
The 63 most common of 64 parts.
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Questions
How big is the Pico expansion board PCB?
It measures 54 × 69 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Pico expansion board use?
64 parts, built around the MAX3485ED, TJA1051T/3/1, 74HC04D and 74HC165D. 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 Pico expansion board KiCad files?
From the Tai-Min/Robo-Bus repository on GitHub, at the commit this page was made from: the board is hw/pico_expansion_board/pico_expansion_board.kicad_pcb and its schematic hw/breakout/breakout.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Pico expansion board design in my own project?
Its repository states no licence, so its author keeps all rights: ask Tai-Min before reusing the design.