Crowdfunded 'PowerWatch' Runs on Body Heat, Never Needs Charging (engadget.com)

Engadget reports on a new watch that suggests the possibility of a future without chargers: This thermal-powered wearable doesn't need one -- it gets energy by converting your body heat into electricity. It's been a year since I saw an early prototype of the PowerWatch -- a smart(ish) watch that tracks basic fitness metrics. Now, the self-proclaimed energy-harvesting company is finally ready to ship PowerWatches to the early adopters who backed its Indiegogo campaign...

Because its functions are pretty basic and its LCD screen is relatively low-powered, it doesn't take too much electricity to keep the watch running... The PowerWatch can not only tell the time, set alarms and timers but also track your activity and sleep... Matrix co-founder Douglas Tham said the PowerWatch will keep running for up to 12 months if you don't wear it, and a PowerSave mode kicks in to conserve energy by killing non-timekeeping functions.

Comments

And

[Anonymous Coward]

It's also been a year since the debunking video existed

Re:Not what was promised

[AmiMoJo]

There are many bullshit claims on their page. "Accurate calorie count" via thermal management... No, skin temperature is not correlated with calorie burn to any useful extent.

They are extremely vague about how they will monitor your sleep quality too. It's not really a smart watch either, it doesn't have any connectivity.

My guess would be that it's a basic LCD watch with step counter built in. The calorie burn and sleep monitor are faked from the step counter data.

Re:Huh?

[hey!]

Watch geek here.

A watch doesn't take much power at all. Digital watches can run for years on tiny, tiny batteries. The classic Casio F-91w, also known at the "al Qaeda watch" runs for seven years on a CR2016 cell which delivers 100 maH at 3V: in other words roughly 1000 joules. That translates to a power draw of 5 microwatts.

Now a smart watch is going to draw a lot more power than that, because it has a processor and probably a part time on luminous display to power. But "a lot more than 5 microwatts" leaves a lot of headroom.

Now there are mechanical watches that are powered by photovoltaics, but combining this with a display could be tricky. But another possibility might be a small dynamo powered by wrist action. Of course non-electronic "automatic" watches have been doing this for decades, but every since Seiko introduced it's "kinetic" watch movements in the mid 80s there have been quartz watches powered by mechanical generators with capacitive storage. Currently Seiko and Swiss manufacturer ETA produce "mechanical quartz" movements.

The question is whether you get more power out of a mechanical generator or a thermoelectric generator. I believe Bulova introduced a thermoelectric quartz watch in the 80s, but it never caught on, where as kinetically powered and photovoltaic powered quartz watches remain quite popular. Undoubtedly the technology has improved since then.