Quote from: Massimo80 on May 02, 2014, 01:31:58 PM

Nice idea, but a device like this would need power

One of the big appeals of ARM-core processors are their low power consumptions. For example, a cortex-M4 core processor with 1.2V core consumes only 33 uW / MHz. At 1.25 MIPS/MHz and 150 MIPS operation, this gives a power consumption of ~4 mW. I believe a large portion of the energy requirements would go towards ECDSA signature verification. I estimated earlier in this thread that an ARM-core processor running at 150 MHz could execute secp256k1 verifies in 20 ms, which at 4 mW represents 80 microjoules per verify. Assuming 2 signature checks per TX and 10 TXs / s, this is 1600 uJ/s or 1.6 mW. So this is very low power.

Of course there are many other activities that will consume power too (reading and writing to the SD card, TCP/IP communication), but I think it is generally agreed that performing the signature checks is the most work and this process can be made fairly low power.

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and an Internet connection. And possibly a wireless connection, if you are unable to get it near an Ethernet cable.

This is actually quite straight forward, as there are both chips that implement TCP/IP and processors with integrated ethernet modules.

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And of course a custom-designed board, which has development and production costs.

Yes, you would need this.

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On the software side, it would require at the very least a TCP/IP stack and network drivers, and probably much more in order to be able to port bitcoind to it.

The TCP/IP stack can come as part of an IC, or as a code library for the processor. Attaching a microcontroller to the internet is routine nowadays. However, implementing all the networking features of bitcoin would still certainly be a lot of work.

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What I'm saying it's not this is not feasible, but it could get much more complex and costly than you think.

I'm starting to feel confident that it is feasible too. But how do you know how complex or costly I think the R&D process would be? I assume it would be a great deal of work. But I am interested in the question "how simple, cheap and low-power can a useful bitcoin node by made?" I think this is an important question.

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And this calls for the main question: why? What would be the purpose of developing, building, selling, buying and running such a device, which can only give a very small benefit to the Bitcoin network and can't perform any useful function at all for his owner?

From my experience, once a project like this is complete and working, people find all sorts of applications.

For example, a lower-power, small and inexpensive bitcoin node could be integrated in certain point-of-sales hardware, or it could come with bitcoin miners and run P2P pool by default (helping to decentralize mining efforts).