Open Source AR Glasses

1.1 General Overview

The first chapter introduces the overall project and introduces the assembly method of the optical part.

Chapter 2 introduces the circuit part and program part of AR in detail.

Chapter 3 introduces you to the current project status.

The entire production process is to assemble the optical part first, then align it with the screen, and then burn the hardware circuit into the firmware.

1.2 Features

OSAR is biased toward exploration and is equipped with a 1920x1080 OLED display. The upper part is a removable the thermal imaging module, after being removed, has an infrared camera inside.

This is the function of watching the drama:

 This is the gesture recognition demo (based on midiapipe):

1.3 Mainboard Principle

To drive the display, there must be a computing platform for support. At the earliest, I tried the direct drive display part of the mobile phone, but I could not call the infrared camera on the glasses. Without the infrared camera, night vision and homemade applications could not run away. I also tried the development board drawn by myself, JLC six-layer gold sinking process, above is Linux, drive optical part is no problem, but can not run Android AR application, that is, can not see the stars can not measure. So is there a solution with good compatibility and complete functions? I thought of the embedded Android module commonly used on this AD machine: RK3399. That is the one in the video, over time, I bought the market In the sale of AR glasses Thunderbird Air, after the market research, I think: 2024 AR industry does not need to be too ambitious, run an Android system, what functions, replace the phone, but do a good job of specialized functions, to toB thinking, in certain occasions to become just need. The reason is no it, the hardware computing power and battery life is not good, so the operation is appropriate. Please look at the architecture diagram below:

You'll find that AR glasses are essentially a monitor and a camera hanging on his face, so he's fine with his phone, computer and development board, including Raspberry Pi. Raspberry Pi was used in early testing (how did I play all the development boards?) But now I choose to modify the h616 based teak school, so that the operation can bring the highest efficiency and cost ratio, help you complete the lowest cost to complete the drama, hot imaging hot fusion, night vision instrument, these core demands, that is, practical and handsome, hot imaging tutorial see the attachment doc document. Main board available mirror:

https://115.com/s/swzzh0c33g7?password=k716
https://115.com/s/swzzw6a33g7?password=l2c0

For detailed information on the motherboard, see the engineering PCB section. The HDMI adapter circuit is required, otherwise it will not work.

I personally recommend that you use JLC SMT. After all, it is difficult to successfully weld the three BGAs on the motherboard at one time.

1.4 Display Part

If you want to assemble, see the 1.4.2 animation disassembly or attachment video, where the bottom blue is the lens (convex lens and semi-permeable and semi-reverse combination)

Can't you see the screen so close to the eye? The lens in the eye can automatically adjust the focus distance, so that we can see the object, but too close to the distance will exceed the focus ability of the eye, that is, can not see clearly. VR's solution is to add a lens in front of the screen to mistake your eyes for objects as far away. AR on the basis of the same principle to also add a semi-permeable and semi-reverse coating, so as to achieve the virtual and real superposition display.

1.4.2 Assembly

The key part of the optical lens, you can buy on Xianyu, it is easy to find, after buying the above lcos part removed, above lcos no open source drive can use, removed after replaced with our own ecx335 screen. The screen can be bought on Taobao. Price is within 850.

In the middle is the glasses frame, OLED, and driver board. The model is ECX335AF. Above is the camera and its bracket.

The first step of assembly is to install the camera and lens to their respective brackets, model number OV5647 (IR)

In the second step of assembly, install the ECX335 into the lower part and strictly align it with the imaging part of the lens, install the driver board to the upper part. The FPC lines of the two are not shown in the picture, but please be careful when installing.

The last step is to glue the upper and lower parts together. It is recommended to use AB glue here. After the bonding is completed, connect the HDMI cable and USB.

The display effect is as shown in the figure: no purple fringing or distortion, but the FOV is not large, and the eye brightness is about 300nit.

Before and after assembly, the weight is 67g, which is okay.

1.5 Open Source Agreement

This project is under the MIT license. Commercial development does not require authorization, and the original author's logo and name cannot be used.

1.6 Project Properties

This project is made public for the first time and is my original project. The project has not won any awards in other competitions.

1.7 Reference:

Yuzuki Chameleon card computer based on H616 - JLC EDA open source hardware platform (oshwhub.com)

The motherboard is modified based on Teak Pie, with USB, HDMI, audio, and Ethernet

Change it to an onboard interface suitable for small spaces, and modify the crystal oscillator material number to match the Lichuang mall library.

1.8 Thermal Imaging

In fact, thermal imaging is essentially a kind of camera, consumer commonly used is usb inside the uvc protocol, the uvc is simple, all kinds of software can decode, even do not need to write their own program. My open this method advantage is that the cost is relatively low, more friendly to individual lovers, after all, is rubbing second-hand goods (music), because this content is relatively large, I made a separate doc attachment, please download and view.