Start small, as in 1 or 2 GPUs. It's easy to add more later. It helps to have the machine be multi purpose so paying back the entire cost would merely be a bonus.

I'm pretty impressed with mine. It works great for upscaling 1080p to 4K, but a carefully tuned desktop with a good GPU does it better. The latter is obviously a lot more expensive, of course. If you're not a hardcore videophile, it will be more than good enough.

Possible but unlikely to be profitable.

I knew a fat, mean girl named Jean Ma in high school. Jean Ma sounds like "golden horse" in Chinese. She's fat so she's massive, so Massive Golden Horse, MGH. That's the formula for potential energy and she's storing a lot of that in the form of fat!

We make life more complex than it really needs to be because it's better that way. Otherwise, we would just be another species of apes...

I use technology to help my best friend who is another special person, even more special in fact.


Speaking of technology, I have been curious about it since preschool, got my first electronics kit in 1st grade, and built my first switching power supply in 4th grade. A very early start on electronics and it definitely paid off!

It's largely a dead coin nowadays, but here's what's left of the community:
https://www.reddit.com/r/perktv/

In my experience, the cheap ZTEs I used for mining Perk would last about 6 months. Back then (2 years ago), it only took a week to break even so it was a good investment.

High end smartphones have never been profitable for mining - they cost way too much for the performance. Cheap smartphones like $20 Moto Es give way more performance per dollar for mining.

I have also tried mining earnhoney with a Pi 3. It is profitable when it runs, but it proved too unstable to be worth running.

Hack some cheap server PSUs to perform MPPT, then parallel the output with unmodified server PSUs to get a constant voltage. Hack the load share to give preference to the solar PSUs, with the normal PSUs supplying the remainder. It will take a lot of electronics knowledge to do it.

I have done that, but on a much smaller scale with one 100W solar panel. The miners (cheap smartphones and small ASIC board) run from a TI DC/DC module. At 89% efficient, it's a bit dated, but works well enough for now. (I plan to replace it with a homemade 96% converter based on a LT chip just for the fun of it.) There's a LiFePO4 battery pack to provide power at night (although the main purpose is as a UPS/Ohmconnect battery for my IT setup) and since the solar panel easily generates more than what the miners use, I have the DC/DC converter (custom design) in my PC to use whatever is left over.

BTW, I would suggest not having a DC bus voltage that can be both higher and lower than the load voltage, since buck boost converters are less efficient than plain buck converters. The reason that was used in my PC was because back then, lead acid was the only economical option for a UPS battery. (And going 24V would require two batteries which doubles the cost.) When that needed replacement, I replaced it with LiFePO4 which is very close to a drop in replacement. If I were to redesign it from scratch, I would use LiMn batteries which is 14.4V nominal for a 4S configuration, so the DC/DC for the PC would only need to be a buck converter.

What would be interesting for larger setups would be to get a hybrid car inverter and hack it to act as a grid tie inverter/rectifier. With continuous power ratings well into the 10s of kW, it would be plenty for a very sizable mining setup. It would also require a very expert level of electronics knowledge.

At one point (over a year ago), it was profitable to mine with cheap ($20 or less) smartphones, but now it won't return enough to break even in a reasonable time.

Solar power. More for the fun of it than anything else, but long story short, I did get pretty popular with many of my friends.

I got in early enough that the hobby practically supports itself.

You actually can if you do it right. Catch is, even a $20 phone is going to take a while - a month or more - to break even, and that doesn't even account for increasing difficulty. The winners are the ones who started early. A further catch is that the few who are making a good profit mining with cheap smartphones are going to keep a secret which coins they're mining so as not to invite a lot of new miners and greatly increase the difficulty.

I recently put together a solar powered altcoin mining setup, used it to help a friend of mine, and got a bit of fame in return.
Background info:
http://www.newsweek.com/naomi-wu-sexy-cyborg-misogyny-silicon-valley-704372
https://www.bunniestudios.com/blog/?p=5046

https://twitter.com/RealSexyCyborg/status/932136250454163458
Probably worth a thread of its own.

The Panasonic GH5 is said to be one of the best "affordable" 4K cameras currently available, but it's still anything but cheap.

On a side note, invest in some LED lights if you film indoors. They're very cheap nowadays. There are many Youtube videos getting great quality from a smartphone by using that trick.

If it's profitable, they'll already be doing it.

Pretty sure a S5 is worth too much to make it worth mining with. Even 2 years ago, when difficulty was considerably lower, $20 for a mining phone was on the expensive side.

You're about a year late since the last time it was worth buying cheap smartphones to mine with. By cheap, that's $20 or less per phone. If you started back then or earlier, it's worth keeping it running (as I do right now), but it's not worth getting started now.

Smartphone CPUs can do better in performance per watt compared to desktop CPUs. They can't compete with GPUs or ASICs, which is why smartphone coins are GPU and ASIC resistant.