Audi DTM Steering Wheel for SimRacing

This project is a remix of the Formula B1 sim racing steering wheel, designed primarily for the Thrustmaster T300 RS wheel base. With an alternative mount or quick-release system, it can also be adapted for other wheel bases.

All buttons are connected to an Arduino Nano using a common ground configuration. The Arduino communicates with the wheel base through a mini-DIN 6-pin connector using the SPI serial protocol. This means the wheel does not use a direct USB connection to the PC, and no external power supply or additional drivers are required.

Official Thrustmaster T300 RS product page: https://www.thrustmaster.com/products/t300rs/

For detailed background information, including Arduino code and communication details, see:
Thrustmaster T300RS Steering Wheel Arduino Emulator Guide

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Features

• Inspired by Audi DTM-style steering wheels
• Designed for the Thrustmaster T300 RS wheel base
• Can be adapted to other wheel bases with a different mount or quick-release system
• Arduino Nano-based button controller
• Common-ground wiring
• No external power supply or direct USB-to-PC connection required

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Bill of Materials (BOM)

• 3D printed parts
• 3 mm aluminum sheet (minimum 300 mm x 170 mm)
• 6D Carbon Black foil (glossy) Aliexpress
• 6x M5 x 70 mm bolts (DIN 7991)
• 6x M5 nuts (DIN 934)
• 4x M3 x 8 mm for panel (DIN 912)
• 4x M3 threaded insert nuts (for panel) Aliexpress
• 6x M3 x 25 mm for handles (DIN 912)
• 4x M3 x 8 mm for paddles (DIN 7991)
• 4x M3 x 8 mm for clutch paddles (DIN 912)
• 10x M3 nuts for handles and paddles (DIN 934)
• 6x M6 x 8 mm for shifter body (ISO 7380-2)
• 6x M4 x 8 mm for shifter body (DIN 7991)
• 6x M4 nut for shifter body (DIN 934)
• 6x M2.5 x 10 for micro-switches in shifter body
• 2x 2.9 mm x 6 mm screw (DIN 7981) for Arduino Nano Terminal Adapter
• 3x aluminum pipe 8 x 6 x 26 mm inserts for extra strength (8 mm outer diameter, 6mm inner diameter and 26mm length)
• 2x A4 Size Suede (Synthetic Leather) for handles Aliexpress
• 6x Neodynium magnet 20 mm x 3mm
• 3x micro-switch for paddles
• 12x 12mm mini switch Aliexpress
• Arduino Nano Aliexpress
• Arduino Nano Terminal Adapter Aliexpress
• Male mini-Din 6 pin connector (for Thrustmaster wheel base)
• Wires

Other components used in this project:

• 70mm Hub Adaptor https://www.thingiverse.com/thing:2630578

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Electronics & Wiring

All buttons share a common ground and connect to individual input pins on the Arduino Nano. The Arduino then communicates with the wheel base through the mini-DIN 6-pin connection using the SPI protocol.

Key points:

• Keep wiring short and secure
• Double-check the pin mapping before uploading firmware
• Use solid solder joints to avoid intermittent inputs
• Add only the inputs you actually plan to use in your build

Refer to the guide here:
Thrustmaster T300RS Steering Wheel Arduino Emulator Guide

Arduino pins - buttons:
D0 - Start (8)
D1 - Select (7)
D3 - L1 (1) - [Shift gear up]
D4 - R2 (9)
D6 - Circle (5)
D7 - Cross (6)
D8 - R1 (2) - [Shift gear down]
D9 - Square (4)
D11 - triangle (3)
A0 - D-Pad up
A1 - D-Pad left
A2 - D-Pad right
A3 - D-Pad down
A4 - L2 (10) - [Clutch]
A5 - PS (13)

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Assembly Instructions

1. Print all parts and clean up any support marks
2. Test-fit the buttons, encoders, and front plate
3. Install the controls in the wheel face
4. Wire everything to the Arduino Nano
5. Secure the Arduino inside the housing
6. Install the mini-DIN connector
7. Close the enclosure and fasten it with screws
8. Mount the wheel to your base

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Printing Recommendations

• Material: PLA for easier printing, PETG for extra durability
• Layer height: 0.2 mm
• Infill: 30–50%
• Supports: Use only where needed
• Orientation: Print the front plate facing upward for the best finish

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Notes

• This is an advanced DIY project and requires soldering and basic electronics knowledge
• If you use a different wheel base, you may need a different mount or quick-release adapter
• The current files are intended as a practical DIY base, so some parts may need to be adapted to match your exact hardware
• Verify compatibility and pin mapping before final assembly
• Sticker are in AUDI_DTM_stickers.pdf file in Thing files.
• Uploaded STEP file is converted from STL file and could be used in CNC service like JLCCNC or PCBWAY.

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Frequently Asked Questions

Can I just connect the Arduino to a PC with USB?
No. This project is designed to communicate with the wheel base through the mini-DIN connection, not as a direct USB game controller.
If you need the Arduino to be directly connected to a PC, refer to the original design here: https://www.thingiverse.com/thing:4058270

How do I connect the double clutch?
The current design does not include a dedicated dual-clutch setup. Adding one would require extra wiring, additional inputs, and firmware changes.

What is the difference between shifter.stl and shifter_magnet_15x2.stl?
shifter_magnet_15x2.stl is made for 15x2 mm magnets. shifter.stl is the standard version.

Is the front plate actually bent?
No, the front plate is flat. Any curve seen in photos is from the camera angle or assembly, not from a bent STL file.

Can I use different paddle switches?
Yes, as long as the switch fits the mount and works with your wiring setup. A small lever micro switch is typically suitable.

Can this work on PS4, PS5, or Xbox?
Compatibility depends on the wheel base and console support. This project is built around the Thrustmaster T300 RS ecosystem.