life span durable ground based 'satellite' device.

So, you should look into RF transponders.

Fine.

They don't need to run on batteries, but you might. Depending on you goals and requirements, you might need rechargable batteries. They would be the first to have problems.

YOu should look over that thread from back in July (21st to be exact) where someone asked about the lifespan of satellites. It got a lot of replies.

Wait, that was you. At least you've figured out a better question to ask.

Michael

could you clarify this...you want the device to STORE the data for years before it is collected?

bad idea...

collect the data on a regular basis so that the data is not lost if the device should fail...

how do you intend to collect the data?

Mark

My initial concern with using a solar panel over a long duration would be environmental. Rain, hail or wind damage, bird droppings, insects, etc. If you're expecting to make this thing operate for decades without any contact, a solar panel would be a poor start.

Tadiran batteries

On a side note, you do need to address how you're going to get your data out of the device...

Chris

Okay, so you have something like a video camera that runs for a few seconds every day, drawing about 5 watts of power. That sounds about right for a video camera.

Radio frequency (RF) transponders? What do you mean by that? Ahh... to sent the data out, you mean. No, this has to be (it probably sounds pretty weird to you) a time capsule. So the data will be retrieved after it's life span. Maybe one radio transmitting at the end to alert people. That will be if it squeezes out it's last bit of power or in case of full HD's or Flash memory.

Yes, I agree. There're batteries which last for 20 years. (shelf-time). This one for example. http://64.233.183.104/search?q=cache:mS6pNL1HhgcJ:nms.csail.mit.edu/fun/battery.ppt+durable+batteries+20+years&hl=nl&gl=nl&ct=clnk&cd=5 But I'm hoping to let the device running longer than 20 years.

I'm curious why the shelf time is strictly limited to about 20 years. These batteries are so durable because the chemicals are separated. So why couldn't it be longer. (there's obviously a good reason for that.... which I don't know yet).

I can remember reading an article long ago that archaeologists found some strange jars in Mesopotamia/Iran/Irak. 2500 years old and filled with crude chemicals. They were batteries. The article said they still gave some current. ....but maybe that part is bogus.

Yes. That was me. Sorry for that. The formulation of the question was way of. ahum.... The reason for that is I didn't want to spoil the idea yet and the analogy with a satellite didn't work out so it backfired. Very smart people started to discuss and advice me about orbit maintenance, radiation shielding and heat isolation. That was kind of stupid of me. My apologies to all the people who contributed all those extensive comments.

I hope this one is better.

Basicly I want to know how long a self sufficient electronic (solid state) device, which consumes about 5 watts a day for =B1 5 second (long enough take a picture (ccd or cmos) and write it on a flash memory module or highly reliable hard disk.... (cheaper but uses more power (=B115 watts))), will last in years and what kind of technology I should use.

I would start by trying to find a MILspec and/or NASAspec on a component that you are familiar with and read it properly to understand what is involved in chosing this part for reliably performing long and unattended activity.

Believe me, such things are "a little awkward" for a group of professional engineers.

Nothing!!! One sample of many components can have a lifespan from zero to whatever and still conform to statistical calculations.

Those are performing past their design limit, just luck.

Being your satelite is earth based have you considered wind?

I want to make this device as an electronic time capsule. When there's almost no energy left or the memory is full (the end of it's functional life), it will transmit a signal and/or sound to make people aware of it's presence. If there are now people, it just stays there till it's found.

CCD/CMOS and sound (microphone)

The minimum power I need, I can get from a 8 square inch solar cell panel. If a make the panel's surface as big as something like 3 square feet I can lose a lot of power.

And maybe rain and decay of organic material will reduce the power loss. I have no information about this issue yet.

Thanks for the link.

I won't. The idea is to make a time capsule full of daily recorded sounds and token pictures.

I agree that my estimate of the size (square meter) of the solar cell panel is far more then enough. That's because I'm not sure what storage media is going to be used. Flash needs only =B11 watt to read/write 1 gb but a hard disc about 15 watts.

Also the panel's power will reduce over years by LID (light-induced degradation).

working on that.

I was already afraid of that. But anyway, I thank you for your comments. :D

Good point. But then you need moveable parts, barings etc. and I might think that these will wear down very quikly by friction and clogging with dirt.

Although somebody just pointed me out Kinetic power watches which are running and generating electrical power for a life time.

KINETIC POWER Some movements are powered by the movement of the wearer of the watch. Kinetic powered quartz watches make use of the motion of the wearer's arm turning a rotating weight, which in turn, turns a generator to supply power. The concept is similar to that of self-winding spring movements, except that electrical power is generated instead of mechanical motion alone. (text:

Can this be scalled up or made in a combo of wind energy?

snipped-for-privacy@doglover.com wrote: ...

...

The "time capsule" idea has some problems; for example, you wouldn't know if the device stopped working a few days after you put it up, and as others have mentioned, could lose all the data at any time.

As far as lifetime goes, proper electronics could last several decades, maybe a century, without any heroic effort. There are scads of 1940's tube radios, 1960's transistor radios, and

However, unexpected problems could shut your thing down at any time and it seems to me that you should expect your first effort to work less than a month before failing, your second one to work less than a year, etc. What climate would your device be in? Will it be sheltered, or out in the dust, rain, snow, wind, and freeze/thaw cycle?

For the long run, I think you would need to build it with no moving parts, which in my opinion rules out wind power, disk drives, motors, pumps, flywheels, automatic cleaning or active aiming of your solar panel, etc. Except for Edison cells, most batteries aren't worth considering. Super-capacitors don't have a long-term proven track record yet, but probably are worth considering. Anyway, all this said, I suggest you use an RTG (radioisotope thermoelectric generator), or a solar-powered TG.

-jiw

Is this building abandoned? I'd think you could schedule at least a yearly walk-around - I know if I owned a building, I'd try to maintain it. ...

I'd shoot for a year, and find a way to get my ass up there and maintain it at least once a year.

Or is this some kind of spy thing, in some restricted area? ;-)

Well, like somebody said, one of those little nuclear thermoelectric pile thingies, but that's a little impractical. Just use some PVs, some decent GelCell batteries (watch your temp. range), and check on it once a year or so.

Or when you lose the signal.

Good Luck! Rich

Use a GSM phone. The have a packet radio mode which sends the bytes fairly cheap. You can also have a two way communication this way.

Rene

Not wanting to sound like a "Free Energy" kook, but you might want to look into how much receive power you could siphon from local AM radio stations. From the numbers you've provided, I came up with you needing less than 300 microwatts continuous (obviously you'd need some charge/collection circuitry). How big an antenna can you tolerate?

It is kinda late...

Chris

From my past in aerospace electronics (including mechanics) mechanical components have much better defined reliability than electronic parts. Just notice the work being done by them in cars. So a solution, when working on a "satelite" is to have experts in every possible technology involved, and hearing pros and cons.

Good luck

Stanislaw

Well you've got a heck of a problem here. Typical electronic stuff these days isnt all that well designed to last. They're chock-full of unreliable components-- switches, connectors, LCD displays, elastomeric connectors, zoom lenses, motors, rubber parts, plastic gears, lubricants, electrolytic capacitors, eproms, flash roms, and probably more. There's no guarantee the camera will last for any length of time.

Even if you buy an expensive, perhaps mil-spec "hi-rel" camera, how do you test it and the rest of the equipment to verify it will last for many years? You probably don't have ten years to waste testing the stuff in real-time, plus at the end of that time, none of the parts will be available, so you'll have to start over qualifying the components.

One method that's often used is to assume, like chemicals, the rate of deterioration doubles for every 10 degrees C, so you could test your setup at say 50 degrees C for 1/8th the expected time. Better test at least ten of the complete systems in parallel so you get some statistical significance in the results. Not easy or cheap, but that's a start at measuring reliability.

The price/reliability curve is quite steep, so you may find it much cheaper to just replace the cameras every X years, or as they fail, than to try to build ultra-reliable ones.

I suspect hard disks are out of the question-- all those moving parts are unlikely to stay well lubed for more than a few years.

Solar cell reliability varies widely depending on type. At the high end are single crystal cells with acrylic encapsulation on the back of glass. Good luck finding one. At the low end are first generation polycrystaline cells silicone encapsulated on the back of glass. This type is readily available, but deteriorates rapidly (several percent per year IIRC) due mainly to water diffusion into the grain boundaries creating shorts and also slightly due to light induced yellowing of the silicone. Prime new second generation polycrystaline cell panels have passivated grain boundaries and have switched back to the more difficult acrylic encapsulation; these are supposedly almost as good as the old single crystal versions, but they are not generally available in small quantities yet since production is not yet able to meet the demand from the few system installers with buying agreements in place. You might be able to persuade a system installer to sell you a second generation panel but you will not find any for sale from distributors that sell panels yet and they are only made in relatively large sizes. So for any small panel you can get easily you should plan on several percent per year reduction in capacity.

Glen