a 100y lifetime project : incredibly difficult ?

[tszaboo]

Someone who is less lazy than me still should work out the math... what would the TOTAL power consumption of the device be over 100 years?

1uA over 100 years is 876mAh so in principle an AA cell or 2477 lithium, but shelf-life is going to be the dominant factor by far with any chemical battery.
I'd say for a solution based on readily available tech, solar plus large value low-leakage capacitor probably has the best chance, as long as it's kept somewhere that  receives some light each day.

Not to mention he wants display.

[charlespax]

There always a nuclear option. It looks like a NanoTritium will last about twenty years. Maybe a few of these?

You can even get one on TaoBao

[ker2x]

Not to mention he wants display.

Some kind of display indeed.
It need a way to show the days. but temporarly , not a permanent display.

[ker2x]

There always a nuclear option. It looks like a NanoTritium will last about twenty years. Maybe a few of these?

You can even get one on TaoBao

Perhaps 
But if they all die of old age after 20y, it won't help to have 1 or many of them 

[charlespax]

Perhaps 
But if they all die of old age after 20y, it won't help to have 1 or many of them 

The page states
The NanoTritium™ betavoltaic power source provides a source of continuous nanoWatt power for twenty years or more in microelectronic platforms. Sounds like it's only a matter of half-life. 

[ker2x]

The page states
The NanoTritium™ betavoltaic power source provides a source of continuous nanoWatt power for twenty years or more in microelectronic platforms. Sounds like it's only a matter of half-life. 

 

Available commercially, the device is expected to be valued in the “couple thousand dollar range” at first, Cabauy said, but in time as the company produces more the price may become less. The battery is currently available in “engineering” quantities, according to the company, up to 1,000 a year, and is assembled in the company’s lab.

[janekm]

Perhaps 
But if they all die of old age after 20y, it won't help to have 1 or many of them 

The page states
The NanoTritium™ betavoltaic power source provides a source of continuous nanoWatt power for twenty years or more in microelectronic platforms. Sounds like it's only a matter of half-life. 

Yeah, but the half-life seems to be around 12 years... The  "capacity-halflife" of the lithium thionyl chloride batteries at <1% self discharge should be >60 years theoretically, but perhaps  they degrade in somer other way.

[sunnyhighway]

Not to mention he wants display.

Some kind of display indeed.
It need a way to show the days. but temporarly , not a permanent display.

Mike already tackled that issue here, by having the display and its display logic powered from a solar power alone. Much like those purely solar powered calculators. No buttons required to activate it either, just supply enough (solar)light to read the display.

[Zero999]

It's certainly possible with today's technology.

There's the Oxford electric bell which is powered from batteries and has been ringing since 1840.
http://en.wikipedia.org/wiki/Oxford_Electric_Bell

[PA0PBZ]

It's certainly possible with today's technology.

There's the Oxford electric bell which is powered from batteries and has been ringing since 1840.
http://en.wikipedia.org/wiki/Oxford_Electric_Bell

Yeah, try to run a clock oscillator and a display from that...

[Phyvel]

Firstly, I haven't the time to read all the comments, I won't pretend to have done so:

Power - Solar could work just fine, given the right amount of cells, it would last an overnight discharge process. However, you'll run into problems during winter, and rainfall. It is entirely possible to keep a container sealed from the elements, with it being glass, even if you have a cable running into it; You simply need to ensure all holes are sealed. Epoxy resins can do this rather well.

Moisture, et cætera - You would be surprised how much heat electronics can survive, for intermittent periods, as it would take to seal a glass container. Regardless, I would try treating the whole thing like a vacuum tube, and flash some kind of "getter" into the sealed container, to remove an gasses which might develop over time; As gases are emitted from glass and other elements over time ... Especially in a vacuum. 

Interface: It could be powered on/off with a magnetic switch. No need for any fancy switching/remotes (which die, or get lost, and replacing them can be difficult, in say, 50 years). Magnets will be around for a looooooong time; some might even say "forever."

PCB: That, I would say, is personal preference. I like seeing things which are like a sculpture, not flat. Those things rarely get done, anymore.

Anyway, good luck. I assume you'll post something herein.

[lapm]

Maybe instruction of maintenance could be made in clay tablets? Some of those has already survived collapse of civilization that created them...

[ker2x]

Firstly, I haven't the time to read all the comments, I won't pretend to have done so:

Power - Solar could work just fine, given the right amount of cells, it would last an overnight discharge process. However, you'll run into problems during winter, and rainfall. It is entirely possible to keep a container sealed from the elements, with it being glass, even if you have a cable running into it; You simply need to ensure all holes are sealed. Epoxy resins can do this rather well.

Moisture, et cætera - You would be surprised how much heat electronics can survive, for intermittent periods, as it would take to seal a glass container. Regardless, I would try treating the whole thing like a vacuum tube, and flash some kind of "getter" into the sealed container, to remove an gasses which might develop over time; As gases are emitted from glass and other elements over time ... Especially in a vacuum. 

Interface: It could be powered on/off with a magnetic switch. No need for any fancy switching/remotes (which die, or get lost, and replacing them can be difficult, in say, 50 years). Magnets will be around for a looooooong time; some might even say "forever."

PCB: That, I would say, is personal preference. I like seeing things which are like a sculpture, not flat. Those things rarely get done, anymore.

Anyway, good luck. I assume you'll post something herein.

The problem with solar+cell is that the cell will die after ~20years
The magnetic switch is a good idea
About sculpture : agreed 

[Zero999]

It's certainly possible with today's technology.

There's the Oxford electric bell which is powered from batteries and has been ringing since 1840.
http://en.wikipedia.org/wiki/Oxford_Electric_Bell

Yeah, try to run a clock oscillator and a display from that...

Come on, you know what I meant. If it couldbe done back then, it can be done today but better.

[FrankBuss]

The problem with solar+cell is that the cell will die after ~20years

Do you have a reference for this? In this posting I wrote about solar cells. And for even higher lifetime, you don't need to exposure it to full sun light, like the solar cell calculators, which work in the shadow or dim artificial lighting, too.

[ker2x]

The problem with solar+cell is that the cell will die after ~20years

Do you have a reference for this? In this posting I wrote about solar cells. And for even higher lifetime, you don't need to exposure it to full sun light, like the solar cell calculators, which work in the shadow or dim artificial lighting, too.

Sorry, misunderstanding here.
i was thinking about battery to support the solar cell but that's not what you wrote. 

[ker2x]

That, would be incredibely awesome if it didn't suck so much power :


Edit : well, i'm assuming it use an insane lot of power compared to what could provide a small solar panel. But i may be wrong.

[FrankBuss]

I see, you meant solar cell + battery cell. Just "solar" means "relating to the Sun", only, for me, if you don't say "solar cell" or "solar panel", but this might be because English is not my native language

A vacuum fluorescent display needs a heated filament. Wikipedia says at least 0.2 W (but it doesn't say if this is per digit or per display). Might work, if you have a big solar panel and a lot of ceramic backup capacitors.

[ker2x]

I see, you meant solar cell + battery cell. Just "solar" means "relating to the Sun", only, for me, if you don't say "solar cell" or "solar panel", but this might be because English is not my native language

A vacuum fluorescent display needs a heated filament. Wikipedia says at least 0.2 W (but it doesn't say if this is per digit or per display). Might work, if you have a big solar panel and a lot of ceramic backup capacitors.

And since english isn't my main language isn't english either : we're in troubles 

[Jeroen3]

There is only one power source capable of supplying a project like this, standalone, for a long time.
A radioisotope thermoelectric generator, the Russians powered lighthouses from that.  I even think electric cars can be equipped with these if they weren't dangerous when opened.

[ker2x]

There is only one power source capable of supplying a project like this, standalone, for a long time.
A radioisotope thermoelectric generator, the Russians powered lighthouses from that.  I even think electric cars can be equipped with these if they weren't dangerous when opened.

Too expensive 

[miguelvp]

It serves Voyager well, maybe a smaller version that don't need that much power?

http://en.wikipedia.org/wiki/MHW-RTG

But back to the solar panels, if a solar calculator can last as long as they do, heck even battery power calculators I do have one that I never changed the batteries and still goes after 20 years with a couple of LR44s (or equivalent).

Actually I opened the case and they are energizers 357 I'm not sure if they are OEM anymore, I do think so.

I can envision an old solar power calculator being around after 100 years, then again not sure how often it's been used, like mine I don't use it but it's around and I power it every now and then, it was the only programmer's decent calculator back then, or at least I thought so. (1990s or so)

[tautech]

Or the 30 yr old Texas Instruments one I have,
BTW Made in China

[janekm]

Solar cell should be fine indeed, so long as it's sufficiently over-dimensioned to allow for the drop-off in power output: http://energyinformative.org/lifespan-solar-panels/

Looks like real-life figures are even better: http://www.engineering.com/ElectronicsDesign/ElectronicsDesignArticles/ArticleID/7475/What-Is-the-Lifespan-of-a-Solar-Panel.aspx

I was curious about the drop-off since a solar cell seems like a fairly stable device to me, looks like it's mostly due to mechanical stresses.

The display output is more tricky in my view... All the obvious choices either have known lifetime issues or not proven yet:

• the liquid crystal in all types of LCDs are known to degrade over time
• E-ink isn't proven and manufacturer claims of 5 years: http://www.eink.com/sell_sheets/pearl_spec_sheet.pdf
• LEDs have a theoretical life expectancy of 20000 - 50000 years (but real-life figures are variable)
• Mechanical devices have obvious wear issues

Any other ideas?

[Rerouter]

a very small flip dot display for the day fields onwards, and an lcd for the hours minutes seconds, that stays on for a few minutes after pushing a button? in my own experience an LCD lasts longer when not constantly on and not in even medium brightness sunlight for extended periods,

I Commonly deal with automotive displays from the early 90's which have suffered mechanical faults but have not faded by any great measure, By mechanical faults it is generally from a poorly designed plastic housing warping over time and stressing the die on glass controllers connections, or the flat flex traces debonding from the material, in the direct sunlight cases,

That on its own would likely be a decent place to look, as there are a large number of automotive LCD clock displays out there, and i have no doubts if you kept a few spares tucked under some cover it would not be cheating as long as it did not loose time while replacing,