Update - US Shipping (28/09/2025) With NZ Post halting all postal services to the US and US territories, I am unable to ship any items to the US and US territories as of now. Once these restrictions have been lifted, I will update the shipping rate to include these areas

The RE_SWC (Rotary Encoder Steering Wheel Controller) is a plug-and-play kit to add a volume knob back into your car

Features:

• Simple, plug-and-play solution. Mount the volume knob to a panel in the car, solder two wires into your stereo's steering wheel control input and you are good to go
• USB powered. Most headunits have female USB connectors for you to plug this into and power up
• MCU: ATtiny414 - Industrial rated
• Interrupt-driven firmware results in a smooth, user-freindly experience
• Built-in USB to UPDI serial converter for easy programming. If you want to tinker with firmware, do so
• Fully open source hardware and firmware. This includes all design files, BOM, firmware, etc

Update - Firmware Version 2.0.0

FW version 2.0.0 makes the RE_SWC compatible with (most likely) every JVC and Kenwood headunit. SWC is achieved with the blue and yellow stripe SWC input wire on the headunit. Read more below

What's in the box:

• 1pc RE_SWC PCB
• 1pc Rotary encoder board
• 1pc JST connector (5-pin SH series)
• 1pc JST connector (2-pin SH series)

Optional Accessories:

• 1pc Aluminium volume knob cover/cap
• 1pc 3D Printed case
• 1pc 0.5m Braided USB C cable (data & power)

SWC Functions

Documentation and Source Code

• Compatibility List
• User Guide
• Video Demo
• Hardware Documentation and Source
• Firmware Source

Compatibility:

• Headunits that support resistance based steering wheel control learning/programming - this includes most Android headunits
• Several named brand headunits support resistance based steering wheel control learning/programming e.g the Sony XAV series, Kenwood DMX5020S, Alpine iLX-W670
• The RE_SWC should be compatible with (most likely) all JVC and Kenwood headunits using the Blue/Yellow SWC input wire

I am building a compatibility list which will be updated as more people confirm functionality with their headunit. If you are unsure whether your headunit is supported, consult the matrix and/or read the headunit's instruction manual, particularly any section regarding steering wheel control input.

Note: I cannot guarantee this will work with your headunit - there is a decent chance it should if I list it as compatible

Why did I make this?

• No kits like this exist: a plug-and-play solution to add a volume knob back into your car. Mount the volume knob to a panel in the car, solder two wires and you are good to go

My headunit does not have a USB socket to power this??

No worries, purchase an automotive 12V to USB adapter and plug this into it.

• Note: The 12V rail in cars is harsh. Do not cheap out on this component

Shipping

Please note, the price of this item is exclusive of GST and/or VAT etc. Any import taxes and duties shall be born by the customer.

Warranty and Returns

I will happily accept warranty claims for products that are DOA. If your headunit is listed as Compatible - Unconfirmed and it ends up being incompatible, I will also happily provide a refund. Buyer's remorse will not be warrantied or refundable.

Regulatory Notice

While care has been taken to reduce EMI and maintain EMC, this product has not been certified. The user must operate this device in a way that is not harmful to important radio stations while also not being affected by these radio stations.