2 layers100 × 80.2 mm
4 layers50 × 50 mm
Magnetic encoder node
pavan1713/Magnetic_encoder_nodeThis repository contains the hardware design and proposed firmware architecture for a compact, robust industrial encoder node intended for robotic and automation systems.
- Size
- 50 × 50 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 36
- Nets
- 71
- Pads
- 199
- Tracks, vias
- 272, 27
- Pours
- 5
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241129)
- Created
- 19 Jun 2026
- Updated
- 19 Jun 2026
Overview
Magnetic encoder node is an open-source printed circuit board by pavan1713, from the pavan1713/Magnetic_encoder_node repository on GitHub. It is a 4-layer board of 50 × 50 mm with 36 parts on 71 nets, routed with 272 tracks and 27 vias.
It is built around the AP63203WU, AS5048A and SP3485EN-Y, with the SS34 among its other parts. Its parts include 15 capacitors, 9 resistors, 4 ICs, 4 diodes and 2 connectors.
Main components
4
AP63203WU
TSOT-23-6-40℃~+85℃@(TA) 1 1.1MHz 22uA 2A 3.3V 3.8V~32V Buck Built-in Fixed Overcurrent Protection、Light load efficient mode、Cycle-by-cycle current limiting、Hiccup current limiting、EMI optimization (spread spectrum) Step-down type Yes TSOT-23-6 DC-DC Converters ROHSDiodes IncorporatedDC-DC Converters
AS5048A
TSSOP-14_4.4x5.0x0.65PTSSOP-14(4.4x5x0.65) New Arrivals ROHSAdvanced Monolithic SystemsUncategorised
SP3485EN-Y
SOP-8SOP-8 RS-485 / RS-422 ICs ROHSYLPTECRS-485 / RS-422 ICs
SS34
SMA(DO-214AC)-55℃~+125℃ 3A 40V 500uA@40V 550mV@3A Independent SMA(DO-214AC) Schottky Diodes ROHSMDDSchottky Diodes
README
README.mdIndustrial Magnetic Encoder Node
Project Type: Hardware Design & Firmware Architecture (Stage 2 Task)
Target Date: 19-06-2026
Project Overview
This repository contains the hardware design and proposed firmware architecture for a compact, robust industrial encoder node intended for robotic and automation systems. The node is designed to read continuous angular position data from a magnetic rotary encoder and reliably transmit it to a host controller over an RS485 multidrop network.
The system is optimized for deployment in electrically noisy industrial environments, specifically in close proximity to BLDC motors and switching power electronics. It leverages high-resolution 14-bit sensing capable of 0.0219° precision.
Key Technical Highlights
1. Hardware Architecture
- Microcontroller: STM32G0B1CBTx (Arm Cortex-M0+, 64 MHz) chosen for its 144KB RAM and extensive DMA support.
- Sensing: AS5048A 14-bit magnetic position sensor communicating via high-speed SPI (up to 10MHz).
- Power Management: Integrated AP63203WU 2A buck converter for stable 3.3V supply from 12V industrial rails.
- Form Factor: 4-layer stackup constrained strictly within a 50 mm × 50 mm footprint.
- RS485 Transeiver: Selected SP3485EN for cost cutting it has 2kw ESD protection but increased it by adding TVS diode array.
2. Firmware & Communication
- RTOS-Driven: Architecture designed around Free RTOS (or equivalent prioritized tasking).
- DMA Optimization: Zero-CPU-load telemetry using dedicated DMA channels for SPI1 (RX) and UART3 (TX/RX).
- Industrial Bus: RS485 half-duplex communication via the SP3485EN transceiver, supporting data rates up to 10 Mbps.
3. Reliability & Protection
- Transient Protection: SM712 TVS diode array for asymmetrical RS485 line protection (+12V/-7V).
- Reverse Polarity: SS34 Schottky diodes to prevent damage during dual-power (12V and USB-C) connection.
- EMI Mitigation: Comprehensive decoupling network (C1-C15) and Ferrite Bead (FB1) for analog supply isolation.
Repository Structure & Deliverables
Hardware (/hardware)
Native KiCad V9.0 project files and manufacturing outputs.
| Deliverable | Location | Description |
|---|---|---|
| Native Project | /hardware | KiCad V9.0 project (.kicad_pro), schematic, and PCB. |
| Gerber Files | /hardware/gerbers | Production-ready Gerber and drill files (X2 format). |
| SVG Exports | /hardware/gerbers_svg | Visual plots of the board layers. |
| BOM | /hardware/BOM/ | Detailed Bill of Materials for assembly. |
Documentation (/docs)
Comprehensive design justifications and operational procedures.
| Document | Link | Description |
|---|---|---|
| Design Document | Design Document | Component selection, power justification, and EMI strategy. |
| Firmware Spec | Firmware Architecture | RTOS task scheduling, DMA allocation, and data flow. |
| Protocol Spec | Protocol Specification | RS485 packet format, CRC-16, and SPI timing. |
| Risk Analysis | Reliability Report | FMEA, dual-power analysis, and failure mitigation. |
| Assumptions | Design Trade-offs | Open questions for production and mechanical constraints. |
Operational Notes
- Power: The node supports dual-power entry. For bench testing, USB-C provides 5V; for deployment, use the 12V industrial terminal.
- Termination: The RS485 bus includes provision for a 120 Ω termination resistor, to be populated if the node is at the bus terminus.
- Validation: For first-time assembly, refer to the Hardware Bring-Up & Validation Protocol located in the
/docsdirectory.
Parts
36| Qty | Value | Footprint | References |
|---|---|---|---|
| 5 | 100n | Diode_SMD:D_0201_0603Metric_Pad0.64x0.40mm_HandSolder | C1, C2, C6, C7, C15 |
| 3 | 22uf | Diode_SMD:D_0201_0603Metric_Pad0.64x0.40mm_HandSolder | C9, C12, C13 |
| 2 | 0.1uf | Diode_SMD:D_0201_0603Metric_Pad0.64x0.40mm_HandSolder | C11, C14 |
| 2 | 10R | Resistor_SMD:R_0603_1608Metric | R4, R5 |
| 2 | 1u | Diode_SMD:D_0201_0603Metric_Pad0.64x0.40mm_HandSolder | C3, C5 |
| 2 | 4K7 | Resistor_SMD:R_0603_1608Metric | R7, R8 |
| 2 | SS34 | Diode_SMD:D_SMA_Handsoldering | D2, D3 |
| 1 | 100pf | Diode_SMD:D_0201_0603Metric_Pad0.64x0.40mm_HandSolder | C10 |
| 1 | 10K | Resistor_SMD:R_0603_1608Metric | R3 |
| 1 | 10n | Diode_SMD:D_0201_0603Metric_Pad0.64x0.40mm_HandSolder | C4 |
| 1 | 10uf | Diode_SMD:D_0201_0603Metric_Pad0.64x0.40mm_HandSolder | C8 |
| 1 | 1k | Resistor_SMD:R_0603_1608Metric | R6 |
| 1 | 5K1 | Resistor_SMD:R_0603_1608Metric | R2 |
| 1 | 5k1 | Resistor_SMD:R_0603_1608Metric | R1 |
| 1 | 6.8uh | Inductor_SMD:L_0201_0603Metric_Pad0.64x0.40mm_HandSolder | L1 |
| 1 | AP63203WU | Package_TO_SOT_SMD:TSOT-23-6 | U3 |
| 1 | AS5048A | Package_SO:TSSOP-14_4.4x5mm_P0.65mm | U2 |
| 1 | Conn_01x04_Pin | Connector_PinSocket_2.54mm:PinSocket_1x04_P2.54mm_Vertical | J2 |
| 1 | FerriteBead | Inductor_SMD:L_0201_0603Metric_Pad0.64x0.40mm_HandSolder | FB1 |
| 1 | Green | LED_SMD:LED_0201_0603Metric_Pad0.64x0.40mm_HandSolder | D4 |
| 1 | J3 | Connector_USB:USB_C_Receptacle_GCT_USB4105-xx-A_16P_TopMnt_Horizontal | J3 |
| 1 | R9 | Resistor_SMD:R_0603_1608Metric | R9 |
| 1 | SM712_SOT23 | Package_TO_SOT_SMD:SOT-23 | D1 |
| 1 | SP3485EN | Package_SO:SOIC-8_3.9x4.9mm_P1.27mm | U4 |
| 1 | U1 | Package_QFP:LQFP-48_7x7mm_P0.5mm | U1 |
Questions
How big is the Magnetic encoder node PCB?
It measures 50 × 50 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Magnetic encoder node use?
36 parts, built around the AP63203WU, AS5048A, SP3485EN-Y and SS34. 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 Magnetic encoder node KiCad files?
From the pavan1713/Magnetic_encoder_node repository on GitHub, at the commit this page was made from: the board is hardware/magnetic_encoder_node.kicad_pcb and its schematic hardware/magnetic_encoder_node.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Magnetic encoder node design in my own project?
Its repository states no licence, so its author keeps all rights: ask pavan1713 before reusing the design.
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