This video camera is powered by light | Hacker News Reader

This video camera is powered by light

cs.columbia.edu

82 pointspraba23089017 comments

That's the elegant solution I love about welding equipment. They realized hrm super bright light source.... lets use solar cells. Need just enough power in battery form to keep the micro alive. Been doing it since way back in the '90s.

As we go increasingly wireless, we become keenly aware of recharging batteries. Consequence is greater interest in "ambient power harvesting". A device powered by its own sensor's energy input is insightful. What next? keyboards powered by typing? trackpad/mouse by clicking & movement? Screens with an extra sub-pixel for light collection? Smart watch "self-winding"?

Backlit screens and backlit watches are never going to be self-powered. It's more feasible that a passive e-paper like display could be self-powered.

Depends on how you define the phrase "self-powered." Today, an "electric-powered" car may not necessarily mean to the exclusion of gasoline as an additional power source.

If a backlit device harvests the unused light from its own backlight, it would surely be powered by itself. Not _purely_, but it would be harvesting its own outputs for energy.

Unused light? What did you mean by that?

Fueling an electric car with gasoline has has nothing to do with self powered ambient harvesting machines. It looks like you're just trying to stretch concepts to suit your initial arguments.

I apologize for not responding sooner.

LCD displays operate by partially blocking or completely blocking the backlight to produce an image. The blocked backlight photons are not used to generate the image. As opposed to a CRT or OLED display, which generate light to produce an image.

What original argument? This is my only comment on this thread. My point was that "X-powered" does not mean "powered-solely-by-X."

They can at least reduce total power, and perhaps store power when not in use.

> Screens with an extra sub-pixel for light collection?

Hmm, that sounds intriguing. You might be on to something.

EDIT: The screen's backlight could be used to (partially) recharge its own battery.

That's a really interesting thought -- after all, the "off" subpixels don't have a job except to sit and block light from passing by.

Combine this with the recent millimeter scale computer motes http://robotics.eecs.berkeley.edu/~pister/SmartDust/ and we get real close to several sci-fi themes such as optical camouflage and universal panopticon.

What happened to make http://robotics.eecs.berkeley.edu/~pister/SmartDust/in2010 so wildly off? Did those projections seem realistic 10 years before? Is it just taking a little longer?

This is very interesting!

"it could lead to a fully self-powered solid-state image sensor that produces a useful resolution and framerate"

In this case would it be able to output colors?

Color just means putting red, green and red filters in front of the pixels in some pattern and so it is definitely not a principle problem but you will lose a large part of the light spectrum for every pixel and therefore harvest a lot less energy.

In theory, you could put the filters on for just a fraction of the time to measure the colors, and spend most of the time collecting all the light. I'm not sure how to do that and stay low power.

You could have separate smaller color sensing pixels, using only a fraction of the surface area.

ETA: There are also transparent solar panels which only absorb UV. If that were tuned for visible colors, you could have three transparent layers over an ordinary panel, and maybe not lose anything.

Use a lens and prism to gather incoming photons, split by wavelength, then harvest and record their intensity.

Can it also be used to power other electronics attached to it, such as a CPU?

URL changed from http://www.engadget.com/2015/04/15/self-powered-camera/, which points to this.

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