Embedded Electronics Engineer Needed – Custom Automotive Volume Knob Controller
Budget: €45 – €60 EUR
I am looking for an experienced embedded electronics engineer to design a custom hardware and firmware solution that adds a physical rotary volume knob to an aftermarket car stereo.
The goal is to create a compact PCB that interfaces with the head unit's steering wheel control (SWC) input and translates rotary knob movement into volume up/down commands. The finished product should provide a smooth, factory-quality user experience with minimal latency and reliable operation in an automotive environment.
This is a custom automotive electronics project. I am looking for someone who can design both the hardware and firmware from scratch.
Project Scope
The engineer will be responsible for designing, developing, testing, and documenting the complete system.
This includes:
Electronic schematic
PCB layout
Firmware development
Prototype testing
Bill of Materials (BOM)
Production-ready design files
Functional Requirements
The finished controller should:
Interface with a Kenwood DMX958XR head unit through the Steering Wheel Control (SWC) input.
Accept input from a rotary encoder or equivalent high-quality rotary control.
Detect clockwise and counterclockwise rotation.
Increase and decrease volume smoothly.
Support continuous scrolling while the knob is rotated.
Have adjustable rotation sensitivity and acceleration.
Feel responsive with virtually no noticeable delay.
Power from a standard automotive 5V supply or USB-C.
Be compact enough to mount behind a dashboard panel.
Preferred Design Approach
The implementation method is left to the engineer; however, possible approaches include:
Microcontroller-based design
Digital potentiometer / digitally controlled resistor network
Resistance ladder simulation
Steering Wheel Control protocol emulation
Analog or digital signal conditioning as required
Possible microcontrollers include (or equivalent):
ESP32
STM32
RP2040
CH32
ATmega
The engineer should recommend the most appropriate architecture.
Hardware Requirements
The PCB should include, where appropriate:
Rotary encoder interface
Microcontroller
SWC output interface
Power regulation
ESD protection
Reverse polarity protection
Automotive noise filtering
Programming interface
Status LED (optional)
Firmware update capability (USB or programming header)
The board should be automotive-grade where practical.
Firmware Requirements
Firmware should include:
Rotary encoder decoding
Debouncing
Adjustable acceleration
Smooth volume changes
Error handling
Stable startup
Low latency response
Expandable architecture for future features
Source code must be included.
Future Expandability
The design should allow room for future additions such as:
Mute button
Track forward/back
Play/Pause
Source selection
Voice assistant activation
Multiple programmable buttons
OLED or LCD status display
RGB status lighting
Bluetooth configuration
Firmware updates
CAN/LIN integration (optional)
Deliverables
Complete schematic
PCB files (KiCad preferred)
Gerber files
Bill of Materials
Assembly drawings
Fully documented firmware
Programming instructions
Prototype build recommendations
Testing procedure
Experience Required
Please apply only if you have experience with:
Embedded systems
PCB design
Automotive electronics
Microcontroller firmware
Rotary encoder implementation
Digital signal processing
Reverse engineering communication protocols (if required)
Low-latency embedded applications
Experience with aftermarket automotive audio systems is a strong plus.
What I'm Looking For
I'm looking for someone who enjoys designing high-quality embedded hardware and can recommend the best technical solution rather than simply following a fixed design. The finished controller should be reliable, responsive, compact, and engineered to a professional standard suitable for long-term use in a custom automotive installation.
The goal is to create a compact PCB that interfaces with the head unit's steering wheel control (SWC) input and translates rotary knob movement into volume up/down commands. The finished product should provide a smooth, factory-quality user experience with minimal latency and reliable operation in an automotive environment.
This is a custom automotive electronics project. I am looking for someone who can design both the hardware and firmware from scratch.
Project Scope
The engineer will be responsible for designing, developing, testing, and documenting the complete system.
This includes:
Electronic schematic
PCB layout
Firmware development
Prototype testing
Bill of Materials (BOM)
Production-ready design files
Functional Requirements
The finished controller should:
Interface with a Kenwood DMX958XR head unit through the Steering Wheel Control (SWC) input.
Accept input from a rotary encoder or equivalent high-quality rotary control.
Detect clockwise and counterclockwise rotation.
Increase and decrease volume smoothly.
Support continuous scrolling while the knob is rotated.
Have adjustable rotation sensitivity and acceleration.
Feel responsive with virtually no noticeable delay.
Power from a standard automotive 5V supply or USB-C.
Be compact enough to mount behind a dashboard panel.
Preferred Design Approach
The implementation method is left to the engineer; however, possible approaches include:
Microcontroller-based design
Digital potentiometer / digitally controlled resistor network
Resistance ladder simulation
Steering Wheel Control protocol emulation
Analog or digital signal conditioning as required
Possible microcontrollers include (or equivalent):
ESP32
STM32
RP2040
CH32
ATmega
The engineer should recommend the most appropriate architecture.
Hardware Requirements
The PCB should include, where appropriate:
Rotary encoder interface
Microcontroller
SWC output interface
Power regulation
ESD protection
Reverse polarity protection
Automotive noise filtering
Programming interface
Status LED (optional)
Firmware update capability (USB or programming header)
The board should be automotive-grade where practical.
Firmware Requirements
Firmware should include:
Rotary encoder decoding
Debouncing
Adjustable acceleration
Smooth volume changes
Error handling
Stable startup
Low latency response
Expandable architecture for future features
Source code must be included.
Future Expandability
The design should allow room for future additions such as:
Mute button
Track forward/back
Play/Pause
Source selection
Voice assistant activation
Multiple programmable buttons
OLED or LCD status display
RGB status lighting
Bluetooth configuration
Firmware updates
CAN/LIN integration (optional)
Deliverables
Complete schematic
PCB files (KiCad preferred)
Gerber files
Bill of Materials
Assembly drawings
Fully documented firmware
Programming instructions
Prototype build recommendations
Testing procedure
Experience Required
Please apply only if you have experience with:
Embedded systems
PCB design
Automotive electronics
Microcontroller firmware
Rotary encoder implementation
Digital signal processing
Reverse engineering communication protocols (if required)
Low-latency embedded applications
Experience with aftermarket automotive audio systems is a strong plus.
What I'm Looking For
I'm looking for someone who enjoys designing high-quality embedded hardware and can recommend the best technical solution rather than simply following a fixed design. The finished controller should be reliable, responsive, compact, and engineered to a professional standard suitable for long-term use in a custom automotive installation.