Mononymous telecom engineer Daniel has designed a smartwatch for the energy-conscious \u2014 using sleep modes and an ePaper display to deliver a LoRa-connected wearable powered solely via harvested solar light.<\/p>\n
“This project started long time ago in 2019, with the idea to build a solar watch that can use LoRa packets to communicate to a receiver at home,” Daniel explains of the Lightink. “Back then I started with a Heltec Wireless Stick Lite and an external [ePaper] display. Then I discovered [Sqfmi’s] Watchy [ePaper smartwatch] and immediately bought one, [but] it didn’t have what I wanted (sleek design, LoRa, and solar), however, I thought it was a very good foundation. Back then, I contributed to Watchy many patches to optimize the display as much as I could, but at some point that was not enough and new hardware was needed.”<\/p>\n
This slick smartwatch delivers near-infinite battery life, thanks to a low-power design and a built-in solar panel. (\ud83d\udcf9: Daniel)<\/p>\n
That search for new hardware led to an entirely new watch, built around an Espressif ESP32-PICO-D4 microcontroller module, a Wio-SX1262 radio for the LoRa connectivity, and a compact 1.54″ ePaper display \u2014 an electrophoretic panel that requires power only when changing states, and which can be powered down entirely while still retaining the last-shown image. Running at 2.7V, below-spec for the parts but seemingly functional, Daniel got battery life up to two months before hitting a wall.<\/p>\n
“The ESP32 takes 28ms to boot, and that uses around 1mA of current,” Daniel explains. “About 60% of the total power was being used by the ESP32 just to boot (not to update or display anything). This is when i had an idea, not boot the ESP32 at all, use a wake-up stub to run RTC [Real-Time Clock] code. I implemented code to handle the SPI communication and to update the region of the display controller buffer. With this I could boot+send+update display in less than 1ms.”<\/p>\n
The firmware executes updates from the ESP32’s low-power real-time clock subsystem to reduce boot times and power draw. (\ud83d\udcf9: Daniel)<\/p>\n
With the new low-power system in place and a compact solar panel \u2014 of the type found on the calculators once-common to everyone’s desk \u2014 the watch’s battery life is, theoretically at least, infinite. “I finally managed to have a watch with battery running [for] nine months,” Daniel says, “until I decommissioned it for a new [hardware revision.] Since then I have polished the code, the case, added LoRa (yeah!), even GPS (was a bad idea), and I am still building the project up.”<\/p>\n
More information is available on Hackaday.io<\/a>, while source code and hardware design files are available on GitHub<\/a> under an unspecified license.<\/p>\n","protected":false},"excerpt":{"rendered":"Mononymous telecom engineer Daniel has designed a smartwatch for the energy-conscious \u2014 using sleep modes and an ePaper…\n","protected":false},"author":2,"featured_media":603918,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[42],"tags":[166,74],"class_list":{"0":"post-603917","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-gadgets","8":"tag-gadgets","9":"tag-technology"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/603917","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/comments?post=603917"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/posts\/603917\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media\/603918"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/media?parent=603917"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/categories?post=603917"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us\/wp-json\/wp\/v2\/tags?post=603917"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}