LightInk: E-ink smartwatch with solar, LoRa and GPS lasts 10 months on single charge

Solar-powered smartwatches are still niche products in the overall market, though that does not mean such watches do not exist. The best-known models are probably Garmin Fenix smartwatches such as the Garmin Fenix 8 that we reviewed back when it launched. On these smartwatches, the solar panel is more or less invisibly integrated into the display.

The so-called LightInk takes a different approach. On this smartwatch, the solar panel is clearly visible and separated from the display. There is another major difference, as the LightInk is not a commercially available product but comes from the DIY scene and therefore cannot simply be bought. Instead, interested users have to assemble the watch themselves. A detailed guide is available. In most cases, users have to have a circuit board manufactured by a service provider, own or have paid access to a 3D printer, and be able to do some soldering.

The LightInk is designed to offer several months of battery life. More specifically, up to 10 months should be possible with the 100mAh battery. There is no accelerometer because it would simply consume too much power. However, LoRa is supported, it uses an E Ink display that remains readable in sunlight and also has a backlight for use in the dark, and there is a speaker as well. GPS is available, but there is no companion app yet, which means the LightInk sits somewhere on the boundary between a regular wristwatch and a smartwatch, at least in this respect.