OpenAR 2.2

OpenAR 2.2 Bluetooth glasses.

Introducing OpenAR 2.2 Bluetooth augmented reality glasses!

With OpenAR 2.1 Thermal glasses we showcased a possible functionality of the OpenAR platform. Now, with OpenAR 2.2, we are enhancing OpenAR with the integration of a Bluetooth module!

OpenAR 2.2 has the same optics and almost identical 3D-printed parts as version 2.0. The largest modification is the addition of an HC-06 Bluetooth module. If you have already built your own OpenAR 2.0 glasses following our instructions, you can simply upgrade them by adding the Bluetooth module. Only minor modifications to the electronic connections are required.

Bluetooth technology opens endless possibilities by enabling wireless communication between devices, in this case, your phone and OpenAR 2.2 glasses.

We developed an Android app to demonstrate how OpenAR’s Bluetooth integration can be leveraged for fun and interactive experiences. The app is a mockup of the classic Flappy Bird game. As the center of photonics research in Finland, we of course named the game Flying Photon! When playing the game, your phone acts as a controller and by tapping the screen, you can make the photon fly. Try to dodge obstacles and aim for a high score!

Images of the Flying Photon game. Note the addition of buttons and a cursor!

How it works

The optics are the same as in OpenAR 2.0. We only had to connect the Bluetooth module to the Blue Pill development board used in OpenAR 2.0. Below is an image of the optical setup for those unfamiliar.

A top-down look at the optical path light takes from the display to the user’s eyes.
  • The LCD display we use is a 240×240 1.3-inch LCD display.
  • The two reflective glasses are cut from a thin large plate of clear glass (possibly flint glass) using a glass cutting tool.
  • The lens is a +3.5-diopter lens taken from a pair of reading glasses that were bought from our local hardware store.
  • The mirror is cut from a rectangular makeup mirror that also was bought from our local hardware store.

And that is pretty much the whole optical setup. Next, we need the rest of the electronics to run the LCD display.

  • HC-06 Bluetooth module. Programming this module to communicate with an Android phone enables wireless interaction with the OpenAR 2.2 glasses.
  • The developer board (CPU) is a STM32 Blue Pill which is programmed using a ST-LINK V2 Programmer. Blue Pill doesn’t have a voltage regulator built into it, so we had to make one ourselves. It requires a couple of capacitors and a 3V3 LDO Voltage Regulator. More information and the complete circuit diagram can be found in the OpenAR 2.0 documentation.
  • The battery is a rechargeable 3.7 V 1500 mAh LiPo battery with an integrated Protection Circuit Module (PCM) bought from a hardware store. A micro-USB charger board is also needed to charge the LiPo battery.

The circuit diagram is included in the OpenAR 2.2 documentation. Note that the optical and headband setup are almost identical to OpenAR 2.0. For this reason, the written documentation only contains what is new in OpenAR 2.2 and OpenAR 2.0 documentation is still the go-to for full assembly instructions. Click to view and download the OpenAR 2.0 documentation.

All the 3D models, f3d files, and the Android app for OpenAR 2.2 can be downloaded below.

Downloads

You can find the OpenAR 2.2 documentation, the Android app, and files here.

Licenses

The OpenAR 3D model files provided in this documentation are under the following license:

OpenAR © 2025 by University of Eastern Finland is licensed under CC BY-NC 4.0. To view a copy of this license, visit https://creativecommons.org/licenses/by-nc/4.0/

The OpenAR demo programs provided in this documentation are licensed under the Apache License, Version 2.0:

 Copyright 2025 University of Eastern Finland

 Licensed under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.