Daniel Ansorregui has developed LightInk, an open-source solar-powered E-ink watch inspired by 90s solar digital watches. It features a 1.54-inch e-paper display and supports Wi-Fi, Bluetooth, LoRa, and GPS, running on a 100mAh battery. The project integrates a custom low-quiescent-power design using a TPS63900 buck-boost converter, capacitive-touch input, and deep-sleep-driven firmware, along with ultra-fast partial e-ink updates (<1 ms active time) and precise RTC timekeeping with drift calibration. It also supports solar-first operation (no dedicated charging IC) and dynamic power gating of peripherals, enabling around 9–10 months of operation on a small battery supplemented by solar power. LightInk specifications: System-in-package – ESP32-PICO-D4 SiP CPU – Dual-core processor @ 240MHz Memory – 520KB SRAM Storage – 4MB flash Wireless – 2.4 GHz Wi-Fi 4 up to 150 Mbps and Bluetooth 4.2 BR/LE connectivity Display – 1.54-inch 200×200 B/W e-Paper panel (GDEH0154D67 or compatible) Audio – 10-15mm piezo electric disc speaker Connectivity […]
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Read more here: https://www.cnx-software.com/2026/04/26/lightink-an-esp32-based-solar-powered-e-ink-smartwatch-with-up-to-10-months-of-battery-life/
