STM32 Embedded Controller – RS-485 Motion & Encoder Control, PCB + FW

Job ID: 40113481

Budget: €10,000 – €20,000 EUR

Embedded HW & FW Engineer – RS-485 Motion Controller PCB (Camera + I/O)

Type: Fixed Price or Hourly
Location: EU preferred, remote possible
Language: English
Duration: Long-term cooperation expected

Project Description

We are looking for an experienced embedded hardware & firmware engineer (freelancer or small SME) to design a controller PCB and firmware for a positioning system with an industrial camera interface, auxiliary power outputs, IMU sensing, and external motion drivers.

The controller actively controls external motion drivers and must read and evaluate position feedback (encoders).
Low-level power stages are external, but driver control logic, encoder handling, IMU integration, safety supervision and state management are core parts of this project.

The system supports two fundamentally different motion control methods, requiring two separate firmware builds (shared codebase allowed).

This is a well-defined industrial control project, not research or a demo board.

Confidentiality & Documentation

Signing a Non-Disclosure Agreement (NDA) is mandatory before sharing detailed technical information.

System Requirement Specification (SRS) and Interface Control Document (ICD) are already prepared and will be provided after NDA execution.

The SRS and ICD clearly define:

system behavior and limits,

RS-485 protocol structure,

driver interaction,

safety and fault handling.

Motion Control Methods (Mandatory)

Control Method A – Step/Dir with encoder feedback

MCU directly generates STEP / DIR / ENABLE signals

External stepper drivers are controlled at signal level

MCU reads absolute encoder position directly (SPI or serial)

Encoder feedback is mandatory and used for:

position validation,

motion supervision,

fault detection and safety logic


Low-level motion control and supervision run inside the MCU

Control Method B – Intelligent driver control with feedback

MCU controls external intelligent motion drivers via RS-485

Motion control loops run inside the external drivers

MCU reads position and status feedback originating from encoders via the driver interface

MCU is responsible for:

command sequencing,

enable/disable logic,

fault detection and recovery,

continuous status and position supervision

Two distinct firmware builds are required.


Scope of Work

Firmware

RS-485 communication

slave towards host system

master/controller towards motion drivers


Encoder feedback handling (mandatory):

absolute position acquisition,

validation and plausibility checks,

safety supervision


IMU integration (mandatory):

TDK InvenSense ICM-42688-P

SPI (preferred) or I²C interface

basic filtering, validation, and diagnostics

Driver control logic:

initialization,

enable/disable sequencing,

fault handling


Command & telemetry protocol (frames, CRC, timeouts, error handling)

Control of:

motion drivers,

MOSFET power outputs,

camera trigger / strobe signals

Deterministic state machine: INIT / IDLE / ENABLED / FAULT

Watchdog and fail-safe behavior

Clean, modular firmware architecture (RTOS not required)

Hardware

MCU controller board:

schematic,

PCB layout (4–6 layers),

BOM and manufacturing files


Power input range: 24–36 V DC

Interfaces:

RS-485,

Industrial camera connector Hirose HR10 (12-pin),

Galvanically isolated Trigger / Strobe / GPIO


Outputs:

3× MOSFET power outputs (≥1 A, 12–48 V),

1 output with autonomous temperature-controlled heating

Sensors:

IMU: TDK InvenSense ICM-42688-P,

on-board PCB temperature sensor


Design for testability (SWD, test points, bring-up access)

Prototype

Manufacture and assembly of 1 fully functional PCB prototype

Basic functional verification

All costs included as a service (no separate material billing)

Camera Interface (Summary)

Isolated Trigger IN

Isolated Strobe / GPIO OUT

Configurable via RS-485

Compatible with standard industrial cameras (Hirose HR10, 12-pin)

Environmental & Reliability Requirements

Operating temperature: –40 °C to +85 °C

Low-pressure operation: reliable operation down to ~1 kPa

no reliance on convective cooling,

thermal design based on conduction and radiation,

conservative derating of MOSFETs and DC/DC converters

Industrial / automotive-grade design practices


Formal certification is not required.

Deliverables

Firmware source code (two motion-control builds)

PCB schematic and layout

BOM and manufacturing data

1× assembled prototype

Short technical documentation and test note


All intellectual property transfers to the client.

Proposal Requirements

Please include:

Short professional introduction

Relevant motion / robotics / industrial control references

Estimated cost or hourly rate

Rough timeline:

Firmware – Control Method A

Firmware – Control Method B

Hardware + prototype


Earliest availability

Confirmation of NDA acceptance and interest in long-term cooperation

Long-Term Cooperation

This engagement is intended as the start of a long-term collaboration, including:

firmware maintenance and extensions,

hardware revisions,

integration and support.


Applicants must be willing to sign an NDA and support the project beyond initial delivery.