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Solar Powered Smartwatch Successfully Crowdfunded on Kickstarter (theverge.com)
An anonymous reader quotes the Verge:
Battery life on smartwatches is, in a word, bad. And while most of today's watches can more or less make it through a day without dying, they're still a far cry from the months or even years that traditional watches can run for. What if you never had to charge your smartwatch? That's the promise of Lunar, a new Kickstarter project that claims to be the world's first solar-powered smartwatch... The company says that the watch can charge off both indoor and outdoor light, and can run off as little as one hour of exposure a day. (The company also includes a traditional inductive charger as a backup.)
As for the watch itself, it's a pretty standard hybrid smartwatch, solar power aside. It'll be able to do basic activity and sleep tracking, offer some limited notification support through a colored LED, and automatically set time zones through a connected smartphone app. Also, given the need for low power consumption for the solar charging to feasibly work, there's no screen on the Lunar. Instead, there's just a ring of LED lights located where hour markers would be.
The campaign reached its funding goal wIthin two days of launching -- and one week later had double that amount, raising a total of $101,987 from 564 backers.
It's not clear if Slashdot readers love or hate smartwatches. Does it make a difference if the watch is solar powered?
As for the watch itself, it's a pretty standard hybrid smartwatch, solar power aside. It'll be able to do basic activity and sleep tracking, offer some limited notification support through a colored LED, and automatically set time zones through a connected smartphone app. Also, given the need for low power consumption for the solar charging to feasibly work, there's no screen on the Lunar. Instead, there's just a ring of LED lights located where hour markers would be.
The campaign reached its funding goal wIthin two days of launching -- and one week later had double that amount, raising a total of $101,987 from 564 backers.
It's not clear if Slashdot readers love or hate smartwatches. Does it make a difference if the watch is solar powered?
is solar powered? no. next question.
[very small print] If you live on Mercury. [/]
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
Maybe I'm missing some sort of killer feature; but it looks like their power budget forced them to axe a pretty substantial percentage of the 'smart'; while still tying the watch to a phone(and the hope that it won't lose most of its utility if the company bleeds out and stops updating their little app) and keeping power draw high enough that you do at least sometimes have to worry about the battery, unlike non-smart watches which draw so little power that the solar ones usually run for the life of the device and the battery powered ones have battery lives in years rather than hours.
I could see the notification LED maybe being useful if you already have your phone's constant demands for attention pared down enough that a simple "$APP$ is bothering you" indicator, without room for displaying 'from', 'subject', or anything of that sort would actually be helpful; but my experience has been that 'social' apps are relentless about their notification spam because user engagement metrics are the stuff of which inflated valuations are built; and email notifications are hard to make helpful without at least knowing you the message is from; or that it has passed a particular set of filter rules; because most mailboxes get a constant torrent of low value chatter.
I, um, guess it's less silly looking than the rubbery-bracelet style activity trackers? And the advertising photos imply that it will make me a rugged outdoorsman enjoying an active lifestyle and adequate vitamin D? Plus, the advanced 'have your watch tell you if the sun has risen or set' feature!
Kickstarter funded startup for solar powered watch ends in disaster as startup discovers that watch size solar panels that are covered by sleeves don't produce enough power to run anything.
Todays best solar panels produce about 15 watts per square foot under ideal conditions (south facing, unshaded direct sunlight). A watch is about 1 square inch (1/144th of a square). So you can start with 1/144th of 15 watts, and under ideal conditions the watch will generate 81 mW. Now you automatically have to divide that in half because you have about 50% nighttime, so the watch has to run on less than 40mW. Now because it still has to work at night, it needs some kind of energy storage, and charging and drawing from that storage will cost you about 15% of your efficiency round trip, so you can take that down to about 35mW. Next, you have to account for more northern climates where your solar load factor is lower because of the amount of atmosphere the light has to pass through, and you have to assume worst case that it will only provide 50% of the rated performance, so now you are down to 17mW. Now, a good microprocessor in sleep mode will draw about 1mA at 3.3V, or about 3.3mW, but during active function will draw around 10mA minimum (33mW). Although Bluetooth Low Energy itself will not use much power for low bandwidth usage, processing that information will require the CPU to be in the active state for a not-insignificant amount of the time. Assume that it will have to spend about 20% of its time actively handling status messages (remember the only way to get a processor that runs on so little power is that it is a 50MHz processor (about the same compute power as a 386 DX). So your average processor power draw should be about 7 mW under normal usage.
All of that adds up to about a 2x power margin, but all of that has one fundamental assumption that kills the concept in the real world: The solar is only effective when pointed in the general direction of the sun. A watch (even without sleeves) will almost never be directly exposed to sunlight for any significant duration. (Note that light from indoor sources only produces about 1% of the energy as direct natural sunlight. That is why sitting in direct sunlight makes you warm, and indoor lighting doesn't).
At the end of the day, a dumb watch would probably work just fine for this sort of thing, since a dumb watch only draws uAs. Once you add any kind of external communication protocol, even if it is BLE, you up the power draw to a level that simply can't be powered by energy harvesting of any kind (be it solar or motion, or anything else). I think they have a very nice design for a solar watch that can probably even work for non-smart usage, but if they think they are going to put anything in this thing that can talk to a smartphone, wifi, or any other wireless device, they are dreaming.
I wish I had a good sig, but all the good ones are copyrighted
Meeting their funding goals isn't the hard part, delivering a product is. Let us know if they manage that. http://www.thegamer.com/failur...
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