Sim HandBrake DIY

🏁 DIY Sim Racing Handbrake (ESP32-S3 USB)

+ Optional Sequential Shifter Support (included in firmware below!)

If there is enough interest, I will also release a full DIY Sequential Shifter design in the future.
The firmware already supports both the handbrake and the shifter.

🔥 Introduction

This is a DIY analog sim racing handbrake designed for PC racing games like rally simulators and track racing titles.
It uses an ESP32-S3 with native USB to act as a plug-and-play HID device — no external Arduino or USB converter needed.

The design is compact, strong, and fully 3D printable, using mostly standard hardware components.

The handbrake works analog, meaning the position directly affects braking force — just like a real hydraulic handbrake.

🎮 Features

• ✅ Analog handbrake (linear position → braking force)
• ✅ USB HID via ESP32-S3 (plug & play on PC)
• ✅ Optional sequential shifter support (via firmware)
• ✅ Fully 3D printable
• ✅ Uses common, easy-to-source hardware
• ✅ Spring-loaded return (compression spring)

🧾 Bill of Materials (BOM)

Electronics

• ESP32-S3 (Super Mini recommended)
• 10K Linear Slide Potentiometer
  👉 https://nl.aliexpress.com/item/1005003684684538.html
• 3-wire cable (for potentiometer connection)

Hardware

• M8 nut
• M8x50 socket head bolt
• M8x16 bolt (1x) 
• M6x12 bolt (1x)
• M3x8 or M3x10 bolts (4x)
• Threaded rod M10 (60–70mm)
• Compression spring
  • Length: 40–50mm
  • Wire thickness: ~2.5mm
  • Outer diameter: max 19mm

Printed Parts

Included in this project:

• Base (Body)
• Lever / Hand lever
• Shaft components
• Lock shaft
• Rings / spacers
• Spring holder
• Lever shaft system
• Horizontal guiding shaft + ring
• Potentiometer bracket (linear mount)
• Top shaft + bolt parts
• Handle

(All parts are included in the STL files)

🧱 3D Printing Notes

For the best surface quality, I used PLA/PETG support interface filament.
This gives a much cleaner finish on supported surfaces compared to standard supports.

Recommended materials:

• PLA → easy to print, good enough for most use cases
• PETG → slightly stronger and more durable

Stronger materials are always possible if you want extra rigidity or long-term durability.

⚙️ How it Works

The handbrake uses a linear sliding mechanism:

• The lever pushes a slider
• The slider compresses a spring
• At the same time, it moves the linear potentiometer
• This gives a smooth analog signal to the ESP32

Important:

• This uses a compression spring, not a tension spring
• The return force comes from pushing the spring back

🔌 Wiring (ESP32-S3)

The potentiometer has 3 pins:

• Middle pin → GPIO (analog input)
• Side pin → 3.3V
• Other side → GND

⚠️ Use 3.3V only, not 5V

The firmware reads this signal and converts it into a USB axis.

💻 Firmware

• Firmware is included with this project
• Supports:
  • Analog handbrake (X-axis)
  • Sequential shifter (2 buttons)

You can use:

• Only handbrake ✔
• Handbrake + shifter ✔

🎮 Setup in Windows

1. Connect the ESP32 via USB

2. Open:

   joy.cpl

    

3. Select the device
4. Click Properties
5. Move the lever → should respond on an axis

Optional:

• Use Calibrate to fine-tune the range

🏎️ In-Game Setup

In games like:

• Assetto Corsa
• Dirt Rally
• iRacing

Simply:

• Assign handbrake → pull lever
• Assign shift up/down → press buttons

⚠️ Notes

• This is a DIY project, some basic technical skills are required
• ESP32 works as a PC USB device only (no direct console support)
• If something is missing or truly incorrect, feel free to report it
• Small improvements or “nice-to-have” suggestions are not needed

🚀 Future Plans

If there is enough interest, I will release:

👉 A full DIY Sequential Shifter (mechanical design) to match this handbrake

❤️ Final words

This project is designed to give you a realistic sim racing experience with minimal cost and maximum customization.

Build it, tweak it, improve it — and enjoy rallying the way it should be. 🏁

🔧 Firmware (Arduino / ESP32-S3)

#include "USB.h"

#include "USBHID.h"

USBHID HID;

const int handbrakePin = 2;

const int upShiftPin   = 6;

const int downShiftPin = 7;

// HID report buffer: 1 byte knoppen, 1 byte X, 1 byte Y

uint8_t report[3];

void setup() {

  Serial.begin(115200);

  pinMode(handbrakePin, INPUT);

  pinMode(upShiftPin, INPUT_PULLUP);

  pinMode(downShiftPin, INPUT_PULLUP);

  HID.begin();

  USB.begin();

  Serial.println("ESP32-S3 USB HID Gamepad gestart!");

}

void loop() {

  // Handrem uitlezen

  int rawHandbrake = analogRead(handbrakePin);     // 0–4095

  int8_t mappedHandbrake = map(rawHandbrake, 0, 4095, -127, 127);

  // Knoppen uitlezen

  bool upShift   = (digitalRead(upShiftPin) == LOW);

  bool downShift = (digitalRead(downShiftPin) == LOW);

  report[0] = 0;

  if (upShift)   report[0] |= 1;

  if (downShift) report[0] |= 2;

  report[1] = mappedHandbrake;

  report[2] = 0;

  // HID report sturen (report ID = 1)

  HID.SendReport(1, report, sizeof(report));

  delay(10);

}