Tablet powered by indoor lighting - help, please?

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Tablet powered by indoor lighting - help, please?

Postby AlienBZ » July 14th, 2013, 6:50 pm

Now that I finally got my tablet from eBay, I'm thinking of making it so that it would be powered by indoor lighting, like a standard photoelectric charged household calculator, which I believe are powered by amorphous solar panels.

For about a week now I did online research on solar powered computerized devices, and a lot of this research turns out to be discussions and how-to's on making photoelectric chargers for cell phones that use the sun as their power source.

However, I'd like to try to come up with a way to use amorphous solar panels to power my tablet the way photoelectric calculators use indoor lighting as their source of energy.

Based on my research, I'm thinking of salvaging the photoelectric panels from discarded/used calculators from secondhand shops and somehow wiring them up and affixing them to the tablet so that the tablet would use indoor lighting as its power source, and I came across a couple of online how-to's that show you how to do this, although these how-to's deal with sunlight as the energy source, although there may be danger of overcharging and damaging the phone if precautions are not taken to go over 5 volts.

I'm wondering if I can somehow adapt or modify the method in these how-to's to use calculator photoelectric panels instead of the sun-powered solar panels from radio shack, and I even did a search on radio shack's website for amorphous solar panels but I came up empty, thus my idea of salvaging photoelectric panels from calculators.

I don't know if my idea has any merits, or even if it will work, but I'd like to experiment with this and try it.

What are your thoughts on this?

If so, is there a better way (but I don't want to have to pay thru the nose for one of these indoor chargers on amazon) of have to make my own amorphous solar panels, (which involves using chemicals and I'd rather not go that route of creating my own panels)?


Below is the link to that how-to for a phone solar charger using the sun as the power source.
http://makezine.com/projects/solar-usb-charger/

And here is the link to a calculator battery mod
http://www.youtube.com/watch?v=pKf-CtvscT0

and here's something about a solar cell salvaged from a calculator
http://www.youtube.com/watch?v=jE-wEOQq-M8

Thanks in advance.
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Re: Tablet powered by indoor lighting - help, please?

Postby st2000 » July 14th, 2013, 8:58 pm

Sorry AlienBZ, but I doubt this will work. Solar powered calculators almost always use passive LCDs. And the power needed for processing is minimal. Compare that power with the power needed by graphic rendering chips and video decompression chips. You will probably find the difference to be several orders of magnitude.

At the proper voltage you might be able to recharge the tablet's batteries when the tablet is off. But until you are able to generate 100s of mAs (perhaps near an Amp) of current at the proper voltage you will probably not be able to sustain the tablet's operations indefinitely.
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Re: Tablet powered by indoor lighting - help, please?

Postby AlienBZ » July 14th, 2013, 10:03 pm

EDIT - since I did not see any signs of a AC/DC power cord connected to that video book, I assumed it was powered from panels such as from old calculators - but how else could it be powered, leaving no sign of a battery/battery charger nor power cord?

however, upon furhter exploration of this guy's website/close examination of one of the images (middle image) on this webpage shows a small circle that seems to be embedded in the side/edge of this video book, I think it may be a port of some kind, possibly a power jack maybe for powering/charging the video player that is embedded in the back of this guy's video book, but I really don't know, this is only my guess.

http://www.thevideobookcompany.com/videobookco_005.htm

I have another thread here in the brainstorm pit about a video book that I'm hoping to create here.

http://forums.hackaday.com/viewtopic.php?f=8&t=3323

I'd like to create a video book similar to that wedding video book I linked to above, but with a larger screen, hence the tablet I bought.

Totally stumped re my inexpensive power source for my video book - help, advice, tips?
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Re: Tablet powered by indoor lighting - help, please?

Postby st2000 » July 15th, 2013, 6:38 am

I'll admit I didn't read all the pages you linked to. So if I miss something speak up. It is likely that people are putting picture frames into these books. That's what I would do. Compared to a tablet, picture frames use slow processors and some decompression hardware. You will (probably) not find: multiple core processors, WIFI radios, GPS radios, Bluetooth radios, Accelerometers, electronic compass, forward facing camera, rear facing camera, camera light, microphone, battery management or even a battery in a picture frame. So the power requirements of a picture frame are (should be) much lower.

The down side, for you, is that they are usually not portable.

Still, I think you will be hard pressed to create a solar charging panel the size of the book to sustain playing a video on a picture frame indefinitely. What will most likely trip you up are the dozen or so LEDs ued to back light the LCD.
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Re: Tablet powered by indoor lighting - help, please?

Postby UAirLtd » July 15th, 2013, 10:30 am

http://www.thevideobookcompany.com/videobookco_007.htm

Battery
  • 9 hours video playing
  • 850 hours standby
  • Rechargeable lithium polymer battery


Have you worked out how many solar panels you will need to power your device? Let me run you through this. Let's say your tablet consumes somewhere around 1Awhile playing video, this is not an unreasonable estimate, it would imply that if you had a 4Ah battery pack, you'd be playing video for 4 hours. At 3.7V nominal, that's a power consumption of 3.7W. This is our target figure, generate 3.7W of energy and you're flying.

So first, let's work out how much energy we actually do have: I'm have to make some massive assumptions and simplifications to give you a ballpark figure. Say you're using a 100W tungsten incandescent light bulb (with luminous efficiency of just 2%, so you're outputting just 2W of light energy. Do you see the problem? 2W output, 3.7W requirement. You need more energy than is output in a form collectable by solar cells by a single incandescent, the other 98W is lost as heat, which incidentally is exactly why incandescents are rubbish unless you intend to also use them for heating your room. (Other lighting isn't any better, we're talking light energy here, unless you like your room unusually bright or you live in a grow house, regardless of which lighting type you use, you'll end up with about the same amount of light energy, just less waste heat).

This is made worse by the fact that you're not going to be covering your entire light with solar panels. Your light is on the ceiling, your solar panels are on the wall. If you assume that the radiation pattern for the light bulb is perfectly spherical, and your solar panel array is 2m away from the light source, you can approximate how much energy per square area is falling on it. the surface area of a sphere is 4/pi r ^2, at r=2 this is about 50m^2. So your 2W of energy at 2m is spread over 50m^2 area, giving you an entire 0.04W/m^2.

This is then made even worse by the fact that solar cells of the type used in calculators are about 10% - 14% efficient. So really you're getting about 5mW of energy per square meter of solar cell using your indoor lighting.

Basically you will NEVER be able to power a tablet of today's technology continuously playing video using solar panels of today's technology (especially not those form pocket calculators) and indoor lighting. Even if you covered all of your walls, floor and ceiling with solar panels, or stripped down your tablet to use a fraction of the energy, or used an unusually large amount of indoor lights, you still won't generate enough energy to run a tablet. Think about it: they don't even make graphing calculators with solar cells because the energy requirement even for those are too high, and all solar powered scientific calculators use a battery too - the solar panels being there only to supplement the battery and prolong its life (a scientific calculator with a solar cell and a flat battery will only work in the daylight-lit rooms); only those very very basic calculators that do basic arithmetic can get away with solar-only operation.

Outdoors is a different question, on a summer's day, we can get a whopping 800W/m^2 to 1000W/m^2 of solar insolation. Compare that you your measly 0.04W/m^2 from indoor lighting. With that amount of insolation, suddenly you're getting 100W/m^2 out of your 10-14% efficient cells, meaning you only need 0.037m^2 of solar panel to run your tablet (that's a panel about two-thirds the size of a sheet of paper).

One alternative feasibility is to use the solar cells to trickle-charge a lithium battery...if you don't mind waiting weeks between each video watching session.
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Re: Tablet powered by indoor lighting - help, please?

Postby modder_mike » July 20th, 2013, 7:52 pm

Actually it still won't work. To charge the battery of a modern tablet, some core systems in the tablet have to be alive to monitor progress and control the charge circuitry. There's a good chance that in an indoor setting, you won't even generate enough power to offset what is consumed by the charging circuitry overhead.

And for that matter, amorphous solar cells are much lower in efficiency that what is noted here - about 6-8% is common for low-cost cells. Consider that the record efficiency for amorphous silicon is currently 13.4% (https://upload.wikimedia.org/wikipedia/ ... encies.png), but this is only achievable in controlled laboratory conditions and is not available in commercial cells.
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Re: Tablet powered by indoor lighting - help, please?

Postby map » October 10th, 2013, 7:59 pm

Thread is old, but man you should Google: 6000T Pocket Power which has a solar panel and a 5000mAh battery, also comes with an a/c charger, a usb cable with different types of power connectors for tablets and cell phones and cost this thing costs $20 shipped to your door. Honestly I don't think it's worth the trouble of engaging in a solar project if there is a $20 solution.
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Re: Tablet powered by indoor lighting - help, please?

Postby JakeBush » November 6th, 2013, 11:21 pm

AlienBZ wrote:Now that I finally got my tablet from eBay, I'm thinking of making it so that it would be powered by indoor lighting, like a standard photoelectric charged household calculator, which I believe are powered by amorphous solar panels.

For about a week now I did online research on solar powered computerized devices, and a lot of this research turns out to be discussions and how-to's on making photoelectric chargers for cell phones that use the sun as their power source.

However, I'd like to try to come up with a way to use amorphous solar panels to power my tablet the way photoelectric calculators use indoor lighting as their source of energy.

Based on my research, I'm thinking of salvaging the photoelectric panels from discarded/used calculators from secondhand shops and somehow wiring them up and affixing them to the tablet so that the tablet would use indoor lighting as its power source, and I came across a couple of online how-to's that show you how to do this, although these how-to's deal with sunlight as the energy source, although there may be danger of overcharging and damaging the phone if precautions are not taken to go over 5 volts.

I'm wondering if I can somehow adapt or modify the method in these how-to's to use calculator photoelectric panels instead of the sun-powered solar panels from radio shack, and I even did a search on radio shack's website for amorphous
solar panel but I came up empty, thus my idea of salvaging photoelectric panels from calculators.

I don't know if my idea has any merits, or even if it will work, but I'd like to experiment with this and try it.

What are your thoughts on this?

If so, is there a better way (but I don't want to have to pay thru the nose for one of these indoor chargers on amazon) of have to make my own amorphous solar panels, (which involves using chemicals and I'd rather not go that route of creating my own panels)?


Below is the link to that how-to for a phone solar charger using the sun as the power source.
http://makezine.com/projects/solar-usb-charger/

And here is the link to a calculator battery mod

http://www.youtube.com/watch?v=pKf-CtvscT0


and here's something about a solar cell salvaged from a calculator
http://www.youtube.com/watch?v=jE-wEOQq-M8

Thanks in advance.

It seems like very effective way of generating electricity... Were you successful? I would love to have similar kind of set up so please share some useful information
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Re: Tablet powered by indoor lighting - help, please?

Postby rodroc » December 3rd, 2013, 4:41 pm

I also have my doubts about this working, but I am sure that there are now plenty of solar powered gadgets, which you can use to get your tablet's battery charged.

Regards
Rod
http://allaboutthepipes.com/ 8-)
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Re: Tablet powered by indoor lighting - help, please?

Postby CalebClarke » December 30th, 2013, 4:16 am

AlienBZ wrote:Now that I finally got my tablet from eBay, I'm thinking of making it so that it would be powered by indoor lighting, like a standard photoelectric charged household calculator, which I believe are powered by amorphous solar panel.

For about a week now I did online research on solar powered computerized devices, and a lot of this research turns out to be discussions and how-to's on making photoelectric chargers for cell phones that use the sun as their power source.

However, I'd like to try to come up with a way to use amorphous solar panels to power my tablet the way photoelectric calculators use indoor lighting as their source of energy.

Based on my research, I'm thinking of salvaging the photoelectric panels from discarded/used calculators from secondhand shops and somehow wiring them up and affixing them to the tablet so that the tablet would use indoor lighting as its power source, and I came across a couple of online how-to's that show you how to do this, although these how-to's deal with sunlight as the energy source, although there may be danger of overcharging and damaging the phone if precautions are not taken to go over 5 volts.

I'm wondering if I can somehow adapt or modify the method in these how-to's to use calculator photoelectric panels instead of the sun-powered solar panels from radio shack, and I even did a search on radio shack's website for amorphous solar panels but I came up empty, thus my idea of salvaging photoelectric panels from calculators.

I don't know if my idea has any merits, or even if it will work, but I'd like to experiment with this and try it.

What are your thoughts on this?

If so, is there a better way (but I don't want to have to pay thru the nose for one of these indoor chargers on amazon) of have to make my own amorphous solar panels, (which involves using chemicals and I'd rather not go that route of creating my own panels)?


Below is the link to that how-to for a phone solar charger using the sun as the power source.
http://makezine.com/projects/solar-usb-charger/

And here is the link to a calculator battery mod
http://www.youtube.com/watch?v=pKf-CtvscT0

and here's something about a solar cell salvaged from a calculator

http://www.youtube.com/watch?v=jE-wEOQq-M8

Thanks in advance.


It really seems very effective to me.. Which system have you use of charging? Share your experience as it will help others a lot.
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