Relativty
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| Relativty | |
|---|---|
| |
| Basic Info | |
| VR/AR | Virtual reality |
| Type | Head-mounted display |
| Subtype | PC-Powered VR |
| Platform | SteamVR |
| Creator | Maxime Coutté, Gabriel Combe |
| Release Date | September 2020 (as Relativty); earlier Relativ design published from December 2017 |
| Price | About US$100 in parts (2018-2019 builds); about US$200 in parts (2020 build) |
| Website | https://github.com/relativty/Relativty |
| System | |
| CPU | Atmel SAM3X8E ARM Cortex-M3 (Relativty Motherboard, 2020 build) |
| Display | |
| Display | 5.5-inch LCD (Relativ builds); 2K dual display (2020 reference build); any PC-compatible display can be used |
| Resolution | 2560 x 1440 (original build) |
| Refresh Rate | 120 FPS (2020 reference build, per the creators) |
| Optics | |
| Optics | Fresnel lenses, 50 mm focal length (January 2018) and 80 mm focal length (February 2019); 40 mm diameter, 50 mm focal length lenses (2020 build) |
| Tracking | |
| Tracking | 3DoF rotational head tracking; experimental webcam-based body tracking |
| Device | |
| Sensors | MPU-6050 IMU (original and 2020 builds) |
Relativty is an open-source 3DOF-tracked VR headset.[1] It is a do-it-yourself virtual reality head-mounted display that hobbyists assemble from a microcontroller, an inertial measurement unit, a small PC display, lenses and 3D-printed parts, and it runs games through SteamVR on a PC.[2] The hardware designs, firmware and SteamVR driver are published on GitHub under the GNU General Public License v3.0.[2]
Maxime Coutté and Gabriel Combe started the project as teenagers in France because they could not afford a commercial headset. An earlier version called Relativ drew press coverage in January 2018, and the project was relaunched with new hardware and software as Relativty in September 2020.[3][4] The creators describe it as "NOT A CONSUMER PRODUCT" and expect users to build it themselves with a soldering iron and a 3D printer. It tracks only the rotation of the head, with three degrees of freedom, and has no built-in controller support.[2]
The original version, published as Relativ, ran on an Arduino Due board.[5][1]
History
Relativ (2017-2019)
The project's GitHub repository was created on 3 December 2017, when Coutté uploaded the first 3D models of the headset; Gabriel Combe made his first contributions to the repository the following day.[6][7] Coutté's Hackaday.io project page for Relativ was created on 20 January 2018.[8]
In the January 2018 README, Coutté wrote that he was 16 years old and lived in a small village in France. He built the headset with his friends Jonas Ceccon and Gabriel Combe and their mathematics teacher Jerome Dieudonne, whom they called "Sensei" and who had started the robotics club the three attended. Coutté wrote that he became interested in VR through the anime Sword Art Online but found the Oculus Rift too expensive, so he and Combe decided to build their own headset for about US$100. The README also says that Atman Binstock, then chief architect at Oculus, advised him to "open source it", after which Coutté rewrote the code from scratch and the team released the project publicly.[5]
Hackaday covered the project on 22 January 2018 under the headline "We Couldn't Afford An Oculus, So We Built One". Al Williams listed the bill of materials as an Arduino Due, a 2K LCD screen, a Fresnel lens and an accelerometer and gyroscope. He reported that the team built it for about 100 euros, a little over US$100 at the exchange rate of the time and under US$150 for builders with their own 3D printer, and that the team expected the screen to be the least predictable cost.[3] The software side used two libraries by the team: FastVR, for building virtual reality scenes in Unity, and WRMHL, which handled communication between Unity and the Arduino.[3][8] Early builders could download Unity demo scenes or make their own applications with the FastVR SDK.[9]
On 20 February 2019 the Arduino Blog described Relativty as a SteamVR-compatible headset that could be made for around US$100. It listed a 3D-printed frame holding a 2560 x 1440 LCD, a pair of 80 mm Fresnel lenses, an Arduino Due and an MPU-6050 sensor that sent head-tracking data to the host system.[1]
By May 2019 the README listed two community-designed housings, by contributors TheYXXY and Vang1, based on a model from Horizon Lab, and marked the founders' original design as deprecated. The new designs used biconvex lenses with a 45 mm focal length. A note dated 17 April 2019 recommended an STM32 "Blue Pill" board instead of the Arduino Due, because the Due code had been reported to throw compiler errors and Due-based trackers had shown stability issues, and said Due support would be phased out. The README from this period told builders they could use the headset with SteamVR and OSVR.[10]
Relativty (2020)
On 9 September 2020 the repository was reset with a "fresh-start" commit, followed by a commit titled "new hardware, software and firmware" and a GPL-3.0 license file.[11][7] The relaunched project was presented as an open-source headset that could be built for about US$200, with full SteamVR support, a 2K display running at 120 frames per second, and experimental body tracking.[12][2] On the project website, Coutté (credited there as Maxime Coutte-Peroumal) wrote that he and Combe were 15 when they built their first headset, and that they started Relativty because they wanted to make their own VR games after watching Sword Art Online.[12]
Hackster.io wrote on 10 September 2020 that the device had "matured significantly" since the build began five years earlier and could now "support any SteamVR game at a DIY price of $200".[4] Hackaday's Al Williams covered the new version on 13 September 2020 and referred readers to the team's earlier headset.[13]
Later development
Community contributors continued to maintain the project after the 2020 relaunch. In May 2023 the README gained a new "current recommended build" guide aimed at a minimum working headset, while the earlier instructions were kept as a legacy build.[2][7] A contribution adding a field of view setting to the driver, written in October 2023, was merged in February 2024 together with a typo fix; these merges were the most recent changes on the repository's master branch as of September 2026.[7] At that time the repository had about 7,200 stars and 389 forks on GitHub.[2]
The current README describes Relativty as a basic 3DoF headset and notes that the lack of controllers limits its use in games that need knuckle-style controllers. For a DIY headset with six-degrees-of-freedom tracking and controller support, it recommends the separate HadesVR project instead.[2]
Design and hardware
Relativty is split into two parts. A microcontroller reads an inertial measurement unit and sends orientation data to the computer over USB, while the display connects directly to the computer and is driven like an extra monitor.[2] Because the display is a standard PC screen, builders can choose any panel their computer can drive; the 2020 project website mentioned options from 90 Hz 1080p screens to 4K panels.[12][13]
The recommended parts changed several times:
| Build | Controller board | Sensor | Display | Lenses | Parts cost stated by the project |
|---|---|---|---|---|---|
| Relativ, January 2018 | Arduino Due | GY-521 MPU-6050 | 5.5-inch 2560 x 1440 LCD with HDMI to MIPI board | Fresnel lens, 50 mm focal length | About US$100[5] |
| Relativ, February 2019 | Arduino Due | GY-521 MPU-6050 | 5.5-inch 2560 x 1440 LCD with HDMI to MIPI board | Fresnel lenses, 80 mm focal length | About US$100[9] |
| Community designs, 2019 | STM32 "Blue Pill" (recommended) | GY-521 MPU-6050 | 5.5-inch 2560 x 1440 LCD with HDMI to MIPI board | Biconvex lenses, 45 mm focal length, 37 mm diameter | Not stated[10] |
| Relativty, September 2020 | Relativty Motherboard (Atmel SAM3X8E ARM Cortex-M3) or Arduino Due | MPU-6050 (MPU-9250 with alternative firmware) | 2K dual display at 120 FPS | 40 mm diameter, 50 mm focal length | About US$200[2][12] |
| Recommended build, May 2023 | ATmega32U4 board such as the Arduino Pro Micro | Any IMU supported by the FastIMU library | Small high-resolution PC display with driver board | 40 mm diameter, 50 mm focal length | Not stated[2] |
The 2020 Relativty Motherboard is a custom printed circuit board built around the Atmel SAM3X8E ARM Cortex-M3 processor with an MPU-6050 IMU. The project website put the cost of the bare board and its components at about US$25, and the build guide said the bare PCB could be ordered for around US$4.[12][2] The firmware is based on ArduinoCore-sam, so it also runs on the Arduino Due or other boards whose processors support the ArduinoCore.[12] The display used in the reference build was a 2K dual display running at 120 frames per second; the README said similar screens cost from US$150 to US$190 depending on the vendor.[2]
The 3D-printable housing is provided as STL files. The 2020 build used a replacement strap and face foam bought separately, and the 2023 guide suggests replacement parts for the HTC Vive. As a simpler alternative to 3D printing, the 2023 guide suggests modifying a smartphone VR case, which often includes interpupillary distance adjustment.[2]
Software
The 2018 and 2019 versions sent sensor data from the Arduino to applications built with the team's FastVR SDK for Unity through the WRMHL library.[3][9]
From 2020, Relativty uses two main software components: firmware on the microcontroller and a SteamVR driver on the PC. The driver is configured through a settings file where the builder enters the USB vendor and product IDs of the microcontroller, the position and resolution of the headset display within the Windows desktop, the interpupillary distance (0.063 m by default in the legacy guide), and two lens distortion coefficients. Builders using the 2023 recommended build upload the Calibrated_relativty example sketch from the FastIMU library; the library's calibration tool can store calibration data on the IMU, which the guide says may help with sensor drift.[2] In the legacy build, the headset calibrates itself a few seconds after it is plugged in while lying on a flat surface.[2]
The 2020 release added experimental body tracking. It uses a webcam and an artificial neural network trained to estimate the user's 3D body position, and requires an NVIDIA GPU because it depends on CUDA. The README states that this method "is nothing close to the precision or freedom of movements of a dedicated sensor".[2] Hackster.io described the feature as room-scaling through the computer's webcam that was "still very much in the experimental stages".[4]
Reception
The Arduino Blog wrote in February 2019 that the device was "clean though fairly basic" and hoped it would be the start of "a truly excellent open source project as features are added".[1] In its 2018 article, Hackaday stressed that the original build was not "just a box to put a phone in like a Google Cardboard".[3] Reviewing the 2020 version, Hackaday's Al Williams contrasted it with homemade headsets that depend on special software, pointed to its full SteamVR support, and wrote that the 3D-printed case "looks great and overall it seems like an impressive design".[13]
See also
References
- ↑ 1.0 1.1 1.2 1.3 "Relativty is a low-cost VR headset you can build yourself". Arduino Blog. 2019-02-20. https://blog.arduino.cc/2019/02/20/relativty-is-a-low-cost-vr-headset-you-can-build-yourself/. Retrieved 2025-07-12.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 2.15 Maxim xyz, Gabriel Combe. "Relativty - Open-source VR headset with SteamVR support". GitHub. Relativty. https://github.com/relativty/Relativty. Retrieved 2026-09-27.
- ↑ 3.0 3.1 3.2 3.3 3.4 Al Williams (2018-01-22). "We Couldn't Afford An Oculus, So We Built One". Hackaday. https://hackaday.com/2018/01/22/we-couldnt-afford-an-oculus-so-we-built-one/. Retrieved 2026-09-27.
- ↑ 4.0 4.1 4.2 Jeremy Cook (2020-09-10). "Relativty Is an Open Source VR Headset You Can Build for $200". Hackster.io. Avnet. https://www.hackster.io/news/relativty-is-an-open-source-vr-headset-you-can-build-for-200-cfe0bd1ec522. Retrieved 2026-09-27.
- ↑ 5.0 5.1 5.2 Maxime Coutté (2018-01-09). "Relativ README (revision of 9 January 2018)". GitHub. Relativty. https://github.com/relativty/Relativty/blob/3f66c2b4f0ae63d09f0fbf33991ab895d3b8cb1a/README.md. Retrieved 2026-09-27.
- ↑ Maxime Coutté (2017-12-03). "Initial commit". GitHub. Relativty. https://github.com/relativty/Relativty/commit/6cc91cde66a6bd9039c7b401bc8922634a5c379c. Retrieved 2026-09-27.
- ↑ 7.0 7.1 7.2 7.3 "Commits - relativty/Relativty". GitHub. Relativty. https://github.com/relativty/Relativty/commits/master. Retrieved 2026-09-27.
- ↑ 8.0 8.1 Maxime Coutte-Peroumal. "Relativ - Build your own VR headset for $100". Hackaday.io. https://hackaday.io/project/36519-relativ-build-your-own-vr-headset-for-100. Retrieved 2026-09-27.
- ↑ 9.0 9.1 9.2 Maxime Coutté (2019-02-08). "Relativ README (revision of 8 February 2019)". GitHub. Relativty. https://github.com/relativty/Relativty/blob/b99274ede8b78a62f09185d4ed821072da05adbc/README.md. Retrieved 2026-09-27.
- ↑ 10.0 10.1 Hugo Garritsen (2019-05-27). "Relativ README (revision of 27 May 2019)". GitHub. Relativty. https://github.com/relativty/Relativty/blob/2231b051acb47fe80c575c2e631e50322f6da477/README.md. Retrieved 2026-09-27.
- ↑ maximecperoumal (2020-09-09). "new hardware, software and firmware". GitHub. Relativty. https://github.com/relativty/Relativty/commit/82b47026d804b60829f3caa03f5add52b44c099e. Retrieved 2026-09-27.
- ↑ 12.0 12.1 12.2 12.3 12.4 12.5 Maxim Perumal, Gabriel Combe (2020). "Relativty an Open-source VR headset for $200". Relativty. https://web.archive.org/web/20251001171107/https://www.relativty.com/. Retrieved 2026-09-27.
- ↑ 13.0 13.1 13.2 Al Williams (2020-09-13). "Open Source VR Headset For $200". Hackaday. https://hackaday.com/2020/09/13/open-source-vr-headset-for-200/. Retrieved 2026-09-27.