Matrix adds a solar cell to its battery-free smartwatch

The company claims it can do GPS and optical heart-rate tracking without a battery.

In announcing the third in its range of battery-free smartwatches, Matrix Industries is going where few others have gone before. Whereas the first two PowerWatches relied upon thermocouples to generate power, the new model has two different ways to get energy. As well as drawing a charge from the heat on your wrist, the PowerWatch 2 will harvest solar radiation to keep itself going.

Adding a solar cell below the dial has given the PowerWatch 2 enough juice to add the sort of features most folks expect from a smartwatch. That includes built-in heart-rate monitoring, a full-color display and, most surprising of all, onboard GPS. The cell is, like with other watches of this type, sat in a ring below the crystal and over the face, so better roll your sleeves up.

Thermocouples and solar cells are old-school pieces of technology that have been used to drive battery free devices for decades. Thermocouples rely upon the difference in temperature between your wrist and the case, using the disparity to generate energy. But that power is only sufficient for a dainty wristwatch, and so Matrix's efforts building a low-power smartwatch have to be applauded.

Similarly, optical heart-rate tracking and GPS are both hugely power hungry, and Matrix says that it's had to work hard to optimize both. The compromise is that you won't be able to run the GPS for longer than 30 minutes a day, and that the heart-rate tracking will be set on intervals. Even that has required the size of the watches capacitor to be doubled, meaning that the PowerWatch 2 is pretty chunky.

The device is currently available for pre-order on Indiegogo, priced at just $200 for early birds, and -- if the company meets its deadlines -- will begin shipping by June. That deadline is firmer than you may expect, as representatives have said that they don't want to repeat the missed deadlines that plagued its first-generation watches.

Update 8/2/19 9:51am: Due to the positive response to the campaign, the company has added a higher-tier timepiece, the PowerWatch 2 Luxe. The limited run of 1,000 pieces comes with a shark mesh stainless steel band in either black or gold, as well as a plated warranty card.