{"id":1001160,"date":"2026-08-14T22:37:24","date_gmt":"2026-08-14T22:37:24","guid":{"rendered":"https:\/\/www.europesays.com\/us\/1001160\/"},"modified":"2026-08-14T22:37:24","modified_gmt":"2026-08-14T22:37:24","slug":"eitwatch-open-source-esp32-s3-smartwatch-implements-planar-eit-hand-gesture-recognition","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/us\/1001160\/","title":{"rendered":"EITWatch open-source ESP32-S3 smartwatch implements planar EIT hand gesture recognition"},"content":{"rendered":"<p>Researchers from Northwestern University have introduced <strong>EITWatch,<\/strong> an open-source ESP32-S3-based EIT (Electrical Impedance Tomography) gesture-sensing system that fits within a standard smartwatch footprint. It relies on a Seeed Studio XIAO ESP32-S3 board and eight electrodes arranged on the back of the case to detect hand gestures via impedance changes caused by muscle and tendon movement beneath the skin.<\/p>\n<p>Unlike <a href=\"https:\/\/pmc.ncbi.nlm.nih.gov\/articles\/PMC13115331\/\" rel=\"nofollow noopener\" target=\"_blank\">other wrist-EIT systems<\/a> that use circumferential electrode bands, EITWatch places all eight electrodes on the back of the smartwatch case. The sensing area consists of a 31 mm electrode ring that fits within a standard 40 mm watch case, while a 20 mm PCB extension carries the discrete analog front end (AFE).<\/p>\n<p><a href=\"https:\/\/www.cnx-software.com\/wp-content\/uploads\/2026\/08\/EITWatch.jpg\" rel=\"nofollow noopener\" target=\"_blank\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-medium wp-image-175517\" title=\"EITWatch\" src=\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2026\/08\/EITWatch-720x480.jpg\" alt=\"EITWatch\" width=\"720\" height=\"480\"   data-eio=\"p\"\/><\/a><\/p>\n<p>EITWatch hardware specifications:<\/p>\n<ul>\n<li>Wireless board \u2013 <a href=\"https:\/\/www.cnx-software.com\/2023\/03\/22\/xiao-esp32s3-tiny-esp32-s3-wifi-4-and-ble-5-0-module-for-iot-ai-robotics\/\" rel=\"nofollow noopener\" target=\"_blank\">XIAO ESP32-S3<\/a>\n<ul>\n<li>SoC \u2013 Espressif <a href=\"https:\/\/www.cnx-software.com\/2021\/01\/02\/esp32-s3-dual-core-wifi-and-bluetooth-le-5-soc-supports-ai-acceleration-for-aiot-applications\/\" rel=\"nofollow noopener\" target=\"_blank\">ESP32-S3R8<\/a>\n<ul>\n<li>CPU \u2013 Dual-core Tensilica LX7 microcontroller up to 240 MHz with vector instructions for AI acceleration<\/li>\n<li>Memory \u2013 512KB SRAM, 8MB PSRAM<\/li>\n<li>Wireless \u2013 Wi-Fi 4 and Bluetooth 5.0 dual-mode (Classic + BLE) connectivity<\/li>\n<\/ul>\n<\/li>\n<li>Storage \u2013 8MB SPI flash<\/li>\n<li>Antennas \u2013 External u.FL antenna for Wi-Fi and Bluetooth<\/li>\n<li>USB \u2013 USB Type-C for power supply and programming<\/li>\n<\/ul>\n<\/li>\n<li>Sensing surface \u2013 8x 2 mm \u00d8 gold-plated stainless steel disk electrodes<\/li>\n<li>Electrode arrangement \u2013 Arranged in a 31 mm diameter ring, with ~11.9 mm adjacent spacing<\/li>\n<li>Analog Front-End (AFE)\n<ul>\n<li>Excitation \u2013 AD5930 waveform generator outputting a 50 kHz sinusoid<\/li>\n<li>Drive \u2013 ADA4841 voltage-to-current drive providing ~1 mA peak-to-peak<\/li>\n<li>Sensing \u2013 AD8220 instrumentation amplifier and AD7450 12-bit SPI ADC<\/li>\n<li>Digital Potentiometers \u2013 AD5270 ICs to set drive current and sense gain<\/li>\n<li>Switching \u2013 4x ADG738 8-channel matrix switches for routing injection and sensing pair<\/li>\n<\/ul>\n<\/li>\n<li>Power supply\n<ul>\n<li>5v Via USB Type-C port<\/li>\n<li>3.7V, 300 mAh battery with 35mA consumption for approximately 8.6 hours of battery life<\/li>\n<li>TLV73325PDBV 2.5 V regulator; 35mA consumption<\/li>\n<\/ul>\n<\/li>\n<li>Dimensions \u2013 60 x 40 mm (6-layer PCB); fits beneath a standard 40 mm watch case<\/li>\n<\/ul>\n<p>Because a flat array cannot wrap around the wrist, EITWatch is using a multi-depth scanning protocol rather than standard adjacent injection. By keeping one electrode as a fixed source and cycling the negative sink through the remaining seven positions, the device can measure various depths and angular current paths, taking 35 impedance measurements per frame at 48 Hz.<\/p>\n<p>\n<a href=\"https:\/\/www.cnx-software.com\/wp-content\/uploads\/2026\/08\/EIT-system-showing-the-electrode-array-AC-signal-excitation-data-acquisition-boundary-measurements-and-image-reconstruction-process.jpg\" rel=\"nofollow noopener\" target=\"_blank\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-175513 size-medium lazyload\" title=\"EIT system showing the electrode array, AC signal excitation, data acquisition, boundary measurements, and image reconstruction process\" alt=\"EIT system showing the electrode array, AC signal excitation, data acquisition, boundary measurements, and image reconstruction process\" width=\"720\" height=\"403\" data-eio=\"p\" src=\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2026\/08\/EIT-system-showing-the-electrode-array-AC-signal-excitation-data-acquisition-boundary-measurements-a.jpeg\"  data- data-eio-rwidth=\"720\" data-eio-rheight=\"403\"\/><\/a>EIT system showing the electrode array, AC signal excitation, data acquisition, boundary measurements, and image reconstruction process<br \/>\n<a href=\"https:\/\/www.cnx-software.com\/wp-content\/uploads\/2026\/08\/EIT-wrist-sensing-setup-showing-the-electrode-array-bone-and-fat-layers-and-EIT-maps.jpg\" rel=\"nofollow noopener\" target=\"_blank\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-175514 size-medium lazyload\" title=\"EIT wrist sensing setup showing the electrode array, bone and fat layers, and EIT maps.\" alt=\"EIT wrist sensing setup showing the electrode array, bone and fat layers, and EIT maps.\" width=\"720\" height=\"405\" data-eio=\"p\" src=\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2026\/08\/EIT-wrist-sensing-setup-showing-the-electrode-array-bone-and-fat-layers-and-EIT-maps-720x405.jpg\"  data- data-eio-rwidth=\"720\" data-eio-rheight=\"405\"\/><\/a>EIT wrist sensing setup showing the electrode array, bone and fat layers, and EIT maps\n<\/p>\n<p>Researchers report that the ESP32-S3 smartwatch runs an ESP-IDF (v5.2+) application which streams the EIT data over Wi-Fi to a PC for logging and classification, reaching a gesture recognition accuracy of 92.5% for held macro-gestures, and 91.5% for micro-gestures like pinches and swipes. The paper also reports that accuracy drops when tested 48 hours later, to 73.2% for macro-gestures and 70.4% for micro-gestures. Accuracy drops further with new users, reaching 63.1% and 55.3%, respectively.<\/p>\n<p>The team also successfully tested an entirely on-device pipeline, using one ESP32-S3 core for data acquisition and the other for signal preprocessing and ExtraTrees inference. This on-device setup continuously draws around 35 mA at 4.3 V. This equates to approximately 8.6 hours of continuous battery life from an idealized 300 mAh battery.<\/p>\n<p>\n<a href=\"https:\/\/www.cnx-software.com\/wp-content\/uploads\/2026\/08\/EIT-Watch-macro-and-micro-gesture-examples-with-corresponding-EIT-signal-maps.jpg\" rel=\"nofollow noopener\" target=\"_blank\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-175515 size-medium lazyload\" title=\"ESP32-S3 EIT smartwatch  macro and micro gesture examples with corresponding EIT signal maps.\" alt=\"ESP32-S3 EIT smartwatch  macro and micro gesture examples with corresponding EIT signal maps.\" width=\"720\" height=\"434\" data-eio=\"p\" src=\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2026\/08\/EIT-Watch-macro-and-micro-gesture-examples-with-corresponding-EIT-signal-maps-720x434.jpg\"  data- data-eio-rwidth=\"720\" data-eio-rheight=\"434\"\/><\/a>The study tested six macro-gestures (Six, Gun, Point, Thumb Up, Stretch, Fist) and five micro-gestures (Swipe Left, Swipe Right, Pinch, Splay, Wrist Flip) alongside a relax class.\n<\/p>\n<p>Previously, we reported on various open-source and DIY smartwatch projects, including the <a href=\"https:\/\/www.cnx-software.com\/2022\/02\/08\/mutantw-v1-an-open-source-esp32-smartwatch-designed-with-autodesk-fusion-360-and-eagle\/\" rel=\"nofollow noopener\" target=\"_blank\">MutantW V1<\/a>, the<a href=\"https:\/\/www.cnx-software.com\/2024\/10\/01\/sensor-watch-pro-turns-the-casio-f-91w-into-a-modular-arm-cortex-m0-based-digital-smartwatch\/\" rel=\"nofollow noopener\" target=\"_blank\">\u00a0Sensor Watch Pro<\/a>, and <a href=\"https:\/\/www.cnx-software.com\/2025\/03\/19\/the-pebble-smartwatch-is-back-with-the-core-2-duo-and-core-time-2-models-running-pebbleos-open-source-firmware\/\" rel=\"nofollow noopener\" target=\"_blank\">Core 2 Duo<\/a>, but none of these support gesture recognition like the EITWatch.<\/p>\n<p>The EITWatch is fully open-source, and all the files, including Altium PCB design files, Gerbers, and BoM, are released under the CERN-OHL-P-2.0 license, while the ESP32-S3 C-based firmware is available under the Apache-2.0 license. You can find all the resources on the project\u2019s <a href=\"https:\/\/github.com\/XuanyouLiu\/EITWatch_Hardware\" rel=\"nofollow noopener\" target=\"_blank\">GitHub repository<\/a>, and for in-depth technical details, check out <a href=\"https:\/\/xuanyouliu.com\/projects\/eitwatch\/#citation\" rel=\"nofollow noopener\" target=\"_blank\">Xuanyou Liu\u2019s website<\/a>. He also posted a <a href=\"https:\/\/www.linkedin.com\/posts\/xuanyouliu_uist2026-hci-wearablecomputing-activity-7492366898362421248-SCl8\/\" rel=\"nofollow noopener\" target=\"_blank\">live demo on LinkedIn<\/a>.<\/p>\n<p><a href=\"https:\/\/www.cnx-software.com\/wp-content\/uploads\/2026\/08\/EITWatch-Overview.png\" rel=\"nofollow noopener\" target=\"_blank\"><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-medium wp-image-175516 lazyload\" title=\"EITWatch Overview\" alt=\"EITWatch Overview\" width=\"720\" height=\"432\" data-eio=\"p\" src=\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2026\/08\/EITWatch-Overview-720x432.png\"  data- data-eio-rwidth=\"720\" data-eio-rheight=\"432\"\/><\/a><\/p>\n<p><img loading=\"lazy\" alt=\"Debashis Das\" class=\"avatar avatar-100 photo lazyload\" height=\"100\" width=\"100\" itemprop=\"image\" src=\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2026\/08\/3746a4b12bb7f9d6ad70fdf2c1886c0ee5dece45404f2945e5efceb71716ca73.png\" decoding=\"async\"  data-eio-rwidth=\"100\" data-eio-rheight=\"100\"\/><\/p>\n<p>Debashis Das is a technical content writer and embedded engineer with over five years of experience in the industry. With expertise in Embedded C, PCB Design, and SEO optimization, he effectively blends difficult technical topics with clear communication<\/p>\n<p><strong>Support CNX Software! Donate via <a href=\"https:\/\/www.cnx-software.com\/donate-cryptocurrencies\/\" rel=\"nofollow noopener\" target=\"_blank\">cryptocurrencies<\/a>, <a href=\"https:\/\/www.patreon.com\/cnxsoft\" target=\"_blank\" rel=\"nofollow noopener\">become a Patron<\/a> on Patreon, or purchase goods on <a href=\"https:\/\/amzn.to\/3SXubZ0\" rel=\"nofollow noopener\" target=\"_blank\">Amazon<\/a> or <a href=\"https:\/\/s.click.aliexpress.com\/e\/_DmGIIRT\" rel=\"nofollow noopener\" target=\"_blank\">Aliexpress<\/a><\/strong>. We also use affiliate links in articles to earn commissions if you make a purchase after clicking on those links.<\/p>\n","protected":false},"excerpt":{"rendered":"Researchers from Northwestern University have introduced EITWatch, an open-source ESP32-S3-based EIT (Electrical Impedance Tomography) gesture-sensing system that fits&hellip;\n","protected":false},"author":3,"featured_media":1001161,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_share_on_mastodon":"0"},"categories":[18],"tags":[58062,705,2719,39081,3742,158,67,132,68,20267],"class_list":["post-1001160","post","type-post","status-publish","format-standard","has-post-thumbnail","category-gadgets","tag-esp32","tag-gadgets","tag-open-source","tag-sensors","tag-smartwatch","tag-technology","tag-united-states","tag-unitedstates","tag-us","tag-wearables"],"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/117096263421295367","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/1001160","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=1001160"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/1001160\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/1001161"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=1001160"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=1001160"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=1001160"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}