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Comment by TeMPOraL | Hacker News Reader

For values of forever equal to ~5-10 years?

I'm not criticizing the article, which is pretty solid, but covers only the power harvesting topic. I'm just commenting on the title ("Designing a Wireless Device That Lives Forever").

I would very much like to see a serious discussion about making electronics live decades. The primary concern would be internal degradation and environmental damages. How to make batteries that last 100 years? How to make solar panels that last so long? How to deal with the fact that today's electronic components are purposefully not designed to last long? That after many years, your uC will likely just give up and die?

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today's electronic components are purposefully not designed to last long

Well, how long do you want them to last? These things aren't designed in a vacuum, you know. If the customer is willing to pay for a CPU that will run reliably for 50 years, someone will produce it. However, given that most consumer electronics are considered disposable, don't be surprised that the components that go into them aren't designed to last very long.

Engineers -- good engineers, that is -- design to Requirements. If the requirement is that something last for 15 years and the Reliability engineers can predict lifespan to +/- 10% accurately, then a good manager will say "make sure it lasts at least 18 years." That ensures a 10% margin beyond what Reliability predicts and it makes sure you don't waste time building a gold-plated product that costs more than people are willing to pay.

Well, I agree. Note that I didn't criticize that fact here. However, I very much dislike the disposability of current products, because this is a harmful way of ensuring repeat purchases through perpetuating waste.

> don't be surprised that the components that go into them aren't designed to last very long

It's not surprising, but it's also not obvious that discrete electrical components like ICs can degrade with use over the span of the years. That's why I mentioned it.

> If the customer is willing to pay for a CPU that will run reliably for 50 years, someone will produce it.

It is a chicken-and-egg problem. No one will pay for such CPU because it costs a lot, and it costs a lot because no one will pay for it for competition and economies of scale to kick in...

Also beware of tin whiskers. NASA itself did some research on the subject because the problem is damn serious. https://nepp.nasa.gov/whisker/

Yes, this is an interesting topic! And even if you can make the hardware survive for a long time, even in harsh conditions (something like this comes to mind: https://sploid.gizmodo.com/this-old-ass-commodore-64-is-stil... ), the surrounding software ecosystem will still be an issue. Everything from compilers for building the firmware to the server side software will have progressed/aged in those decades.

Good Engineering Practice suggests that you archive the entire toolchain in case you need to make updates 15 years later.

You'll enjoy this article: "The Egg of the Phoenix: a computational time capsule", which discusses: "Could you build a portable computer that would still work if you buried it in the ground for a century?"

http://canonical.org/~kragen/eotf/

If you find the question of forever interesting, the Long Now Foundation may be of interest. They have more far reaching goals, but one of their projects is a clock that can run for 10,000 years with little to no human intervention.

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