{"id":2236,"date":"2026-11-09T12:38:51","date_gmt":"2026-11-09T10:38:51","guid":{"rendered":"https:\/\/sites.uef.fi\/openar\/?page_id=2236"},"modified":"2026-11-09T12:38:52","modified_gmt":"2026-11-09T10:38:52","slug":"openar-s","status":"publish","type":"page","link":"https:\/\/sites.uef.fi\/openar\/openar-s\/","title":{"rendered":"OpenAR-S"},"content":{"rendered":"\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"886\" height=\"382\" src=\"https:\/\/sites.uef.fi\/openar\/wp-content\/uploads\/sites\/263\/2026\/11\/image.png\" alt=\"\" class=\"wp-image-2237\" srcset=\"https:\/\/sites.uef.fi\/openar\/wp-content\/uploads\/sites\/263\/2026\/11\/image.png 886w, https:\/\/sites.uef.fi\/openar\/wp-content\/uploads\/sites\/263\/2026\/11\/image-300x129.png 300w, https:\/\/sites.uef.fi\/openar\/wp-content\/uploads\/sites\/263\/2026\/11\/image-768x331.png 768w\" sizes=\"auto, (max-width: 886px) 100vw, 886px\" \/><\/figure>\n\n\n\n<p>OpenAR-S (S for Scan) is a tiny AR device that listens to Bluetooth Low Energy advertisements and displays the information in the user\u2019s field of view. This model emphasizes low weight and ergonomics, utilizing the smallest possible components you can find with pocket money as of 2026. With components costing roughly 35 \u20ac, model S is the smallest and most accessible device in the OpenAR family.<\/p>\n\n\n\n<p>The program turns an ESP32-C3 development board into a real-time Bluetooth receiver. It listens passively for RuuviTag Bluetooth Low Energy (BLE) advertisements, decodes their sensor data, and displays the information from a single tag on a small OLED screen. RuuviTags periodically broadcast information such as their MAC address, signal strength (RSSI), temperature, humidity, pressure, battery voltage, and movement data without requiring an active connection. The program can monitor multiple RuuviTags simultaneously; the displayed tag is selected based on signal strength and freshness as an estimate of proximity.<\/p>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"671\" height=\"390\" src=\"https:\/\/sites.uef.fi\/openar\/wp-content\/uploads\/sites\/263\/2026\/11\/image-3.png\" alt=\"\" class=\"wp-image-2240\" style=\"width:543px;height:auto\" srcset=\"https:\/\/sites.uef.fi\/openar\/wp-content\/uploads\/sites\/263\/2026\/11\/image-3.png 671w, https:\/\/sites.uef.fi\/openar\/wp-content\/uploads\/sites\/263\/2026\/11\/image-3-300x174.png 300w\" sizes=\"auto, (max-width: 671px) 100vw, 671px\" \/><figcaption class=\"wp-element-caption\"><em>Sensor data photographed through the glass plate. Note, the large size of the text is an artefact of taking the photo from a distance. When worn, the text is fully visible and sharp.<\/em><\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Features<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Small components:<\/strong> This model explores what can be achieved by reducing the size of the components without increasing the cost or requiring specialized tools. The weight of the device has been cut by more than half compared to the previous models, significantly improving the user experience.<\/li>\n\n\n\n<li><strong>Redesigned frame:<\/strong> The frame of the headset resembles regular eyeglasses and makes use of curves and smooth surfaces to improve aesthetics. As the headset is light, it doesn\u2019t require fasteners to be worn, but an ordinary cord with a lock can be attached to keep the headset secure.<\/li>\n\n\n\n<li><strong>Moving parts:<\/strong> Model S has few bolts, instead relying on friction and snap covers to keep things in place. The reflective glass plate can be placed both in front of the left or the right eye, or you may use two identical plates.<\/li>\n\n\n\n<li><strong>Software: <\/strong>The provided example code passively scans for BLE advertisements\u2014namely, data broadcast by nearby RuuviTag sensors. The headset, therefore, works as a handsfree reader or monitor. The main principle of listening to nearby devices via Bluetooth can easily be adjusted to individual needs.<\/li>\n\n\n\n<li><strong>Wireless and rechargeable:<\/strong> The device operates on a 400 mAh battery that can be charged through the USB port. Under normal operation, a fully charged battery may last up to eight hours before needing to be charged.<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"886\" height=\"597\" src=\"https:\/\/sites.uef.fi\/openar\/wp-content\/uploads\/sites\/263\/2026\/11\/image-2.png\" alt=\"\" class=\"wp-image-2239\" style=\"aspect-ratio:1.48411107930146;width:625px;height:auto\" srcset=\"https:\/\/sites.uef.fi\/openar\/wp-content\/uploads\/sites\/263\/2026\/11\/image-2.png 886w, https:\/\/sites.uef.fi\/openar\/wp-content\/uploads\/sites\/263\/2026\/11\/image-2-300x202.png 300w, https:\/\/sites.uef.fi\/openar\/wp-content\/uploads\/sites\/263\/2026\/11\/image-2-768x517.png 768w\" sizes=\"auto, (max-width: 886px) 100vw, 886px\" \/><figcaption class=\"wp-element-caption\"><em>In model S, the reflective glass plate is easy to move according to individual needs.<\/em><\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Optical design<\/h2>\n\n\n\n<p>OpenAR-S places the optical components in front of the head. The components are designed to be small to avoid excess weight and pressure on the nose.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"939\" height=\"408\" src=\"https:\/\/sites.uef.fi\/openar\/wp-content\/uploads\/sites\/263\/2026\/11\/image-1.png\" alt=\"\" class=\"wp-image-2238\" srcset=\"https:\/\/sites.uef.fi\/openar\/wp-content\/uploads\/sites\/263\/2026\/11\/image-1.png 939w, https:\/\/sites.uef.fi\/openar\/wp-content\/uploads\/sites\/263\/2026\/11\/image-1-300x130.png 300w, https:\/\/sites.uef.fi\/openar\/wp-content\/uploads\/sites\/263\/2026\/11\/image-1-768x334.png 768w\" sizes=\"auto, (max-width: 939px) 100vw, 939px\" \/><figcaption class=\"wp-element-caption\"><em>The OLED display emits light towards the glass plate, which transmits most of the incident light. The mirror\u2013lens system collimates the light and reflects it back. Once light arrives at the glass plate for the second time, most is transmitted but some will be reflected toward the eye. These reflected rays form the image the user sees.<\/em><\/figcaption><\/figure>\n\n\n\n<p>Due to the small size of the components, they must be aligned properly for the image to reach the eye. To make the alignment process easy, the headset utilizes very few bolts. Instead, the mirror and the glass plate can be slid into place along the groove in the frame.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">How to make it<\/h2>\n\n\n\n<p>To build the OpenAR-S glasses, we used the components listed below. Note that these are only examples; many, if not all, can easily be replaced with suitable alternatives. The links lead to retailers where you can order the components or find their technical specifications.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Display<\/strong>: <a href=\"https:\/\/fi.farnell.com\/midas\/mdob064032av-wi\/oled-graphic-display-cob-64-x\/dp\/3154936?srsltid=AfmBOopE5JyLhm0cJiYb_kBAb9VPE1Q6Dz_GOaf7POpNOu6uXlJAtsFw\">64&#215;32 OLED display<\/a> (9.50 \u20ac)<\/li>\n\n\n\n<li><strong>Glass plate<\/strong>: Cut from a painting frame (2 \u20ac)<\/li>\n\n\n\n<li><strong>Lens<\/strong>: Cut from +3.5 diopter reading glasses (3 \u20ac)<\/li>\n\n\n\n<li><strong>Mirror<\/strong>: Cut from a makeup mirror (2 \u20ac)<\/li>\n\n\n\n<li><strong>Development board<\/strong>: <a href=\"https:\/\/fi.farnell.com\/en-FI\/seeed-studio\/113991054\/development-board-risc-arduino\/dp\/4060379\">XIAO Seeed Studio ESP32C3<\/a> (5.50 \u20ac)<\/li>\n\n\n\n<li><strong>Battery<\/strong>: Rechargeable&nbsp;<a href=\"https:\/\/www.akkuasiantuntija.fi\/fi\/artiklar\/beats-studio-buds-charging-case-ym.html\">3.8 V 400 mAh LiPo battery<\/a> (9 \u20ac)<\/li>\n\n\n\n<li><strong>Switch<\/strong>: 3-pin ON\/ON <a href=\"https:\/\/partco.fi\/tuote\/1-napainen-liukukytkin-on-on-4857\">slide switch<\/a> (0.50 \u20ac)<\/li>\n\n\n\n<li><strong>Accessories<\/strong>: Wires, bolts, cord, filament, heat-shrink tubing, foam rubber, tape\u2026 (~5 \u20ac)<\/li>\n<\/ul>\n\n\n\n<p>Let\u2019s put the total cost at roughly 35 \u20ac! The exact price will vary depending on the supplier, availability, and shipping costs. Note that the optical components do not need to be of high quality; even scrap glass may suffice.<\/p>\n\n\n\n<p>The frame of the glasses can be 3D printed using regular PLA filament. The 3D-printed components may require modifications to ensure a comfortable fit.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Downloads<\/h2>\n\n\n\n<p>Click the following links to download the files.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/studentuef.sharepoint.com\/:u:\/r\/sites\/www-documents\/Jaetut%20asiakirjat\/Forms\/AllItems.aspx?id=%2Fsites%2Fwww%2Ddocuments%2FJaetut%20asiakirjat%2FOpenAR%2DS%20Full%20archive%2Ezip&amp;parent=%2Fsites%2Fwww%2Ddocuments%2FJaetut%20asiakirjat&amp;p=true&amp;share=cQq%5FwKFHi9k2Qrly6dEhpUrAEgUCXrsSobRhY73dR7C0c85S1w\">Full archive<\/a>, incl. documentation, assembly instructions, 3D models, and software (2 MB)<\/li>\n\n\n\n<li><a href=\"https:\/\/studentuef.sharepoint.com\/:b:\/r\/sites\/www-documents\/Jaetut%20asiakirjat\/Forms\/AllItems.aspx?id=%2Fsites%2Fwww%2Ddocuments%2FJaetut%20asiakirjat%2FOpenAR%2DS%20Documentation%2Epdf&amp;parent=%2Fsites%2Fwww%2Ddocuments%2FJaetut%20asiakirjat&amp;p=true&amp;share=cQpmNsK45krHRJaydta4ndGUEgUCchKr5UviRUGsUS%5FlrITsBA\">Documentation<\/a> (PDF)<\/li>\n<\/ul>\n\n\n\n<p>The documentation provides a listing of the 3D components and their features, explains the optical design and electronic components in detail, and highlights the main features of the provided example code. This document is more general in nature and helps you to understand how the glasses work, underlining some critical concerns from a design perspective.<\/p>\n\n\n\n<p>The assembly instructions contain a full parts listing, the settings we used for 3D-printing, detailed instructions for preparing the optical components, a circuit diagram for soldering, a guide for uploading the ino-file to the Arduino board, and finally the step-by-step assembly of prepared components. It will walk you through manufacturing your own copy of the OpenAR-S glasses.<\/p>\n\n\n\n<p>The 3D models include a F3D file for modeling software such as Autodesk Fusion. The STL file is a slice-ready file for Bambu Studio. The Arduino code is provided in the INO file.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Licenses<\/h2>\n\n\n\n<p><strong>3D models<\/strong>: OpenAR \u00a9 2026 by University of Eastern Finland is licensed under CC BY-NC 4.0. To view a copy of this license, visit <a href=\"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/\">https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/<\/a><br><br><strong>Demo program<\/strong>: Copyright 2026 University of Eastern Finland. Licensed under the Apache License, Version 2.0 (the \u201cLicense\u201d); you may not use this file except in compliance with the License. You may obtain a copy of the License at&nbsp;<a href=\"https:\/\/www.apache.org\/licenses\/LICENSE-2.0\">https:\/\/www.apache.org\/licenses\/LICENSE-2.0<\/a>. Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an \u201cAS IS\u201d 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.<\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>OpenAR-S (S for Scan) is a tiny AR device that listens to Bluetooth Low Energy advertisements and displays the information in the user\u2019s field of view. This model emphasizes low weight and ergonomics, utilizing the smallest possible components you can find with pocket money as of 2026. With components costing roughly 35 \u20ac, model S [&hellip;]<\/p>\n","protected":false},"author":1405,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"class_list":["post-2236","page","type-page","status-publish","hentry"],"acf":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.6 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>OpenAR-S - OpenAR<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/sites.uef.fi\/openar\/openar-s\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"OpenAR-S - OpenAR\" \/>\n<meta property=\"og:description\" content=\"OpenAR-S (S for Scan) is a tiny AR device that listens to Bluetooth Low Energy advertisements and displays the information in the user\u2019s field of view. 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