Since my last post clearly outlining why bitcoin should not be mined with a smartphone, not now, not in the future, people still keep posting in this thread. It's still being treated like it's an opinion piece while in reality this thread should rely on simple math.

Since my previous post didn't do the trick, i'll simply do the maths proving once and for all that mining with a cellphone should not be done...

Let's take a "normal" cellphone CPU: a Cortex-A9. https://en.bitcoin.it/wiki/Non-specialized_hardware_comparison#Other teaches us this CPU is hashing at a whopping speed of 1,3 Mh/s. If you underclock this CPU and it runs at 0.57 Mh/s, it draws 0.5 Watt. Let's just assume that making this cpu hash @ 1.3 Mh/s also draws 0.5 Watt (eventough it won't).

Let's take the current difficulty of 5949437371609

Let's take the current block reward of 12.5 BTC + 0.12 BTC in fees = 12.62 BTC

Now... Let's plug these numbers into the formula to calculate how much BTC you'll mine on average with such a CPU:
(((1300000 * 12.62  * 600 * 65535) / 2^48) / 5949437371609) * 6 * 24) = 0.000000000055 BTC/day = 2 satoshi per year!

An "average" pool seems to have a payout threshold of ~0.005 BTC (https://www.f2pool.com/help/?). So, in reality, it'll take 250000 years to reach the minimum payout treshold.

If you decide to solo mine, it'll take (on average) 631.000.000 years to solve a block (yes, that's 631 million years).

During these 631 million years, you'll have burned 2,7 TerraWattHour, i doubt the block reward will cover the power costs. Do realise that every 210000 blocks, the block rewards will halve... Cutting in your profits.

Now for the people continueing to claim that in the future you'll be able to mine with your cellphone: just look at the above formula... If, some day, cellphones will have chips that are as performant as current ASIC's, the ASIC company's WILL have access to the same technology. An ASIC is built for the sole purpose of creating sha256d hashes, it will ALWAYS be more performant than a CPU...
So, in the future, the only 2 things that can happen are:
- bitcoin might be worthless, so ASIC companies are not interested in creating new ASIC's, the future CPU's become more performant than the old ASIC's and you'll be able to mine worthless coins
- if bitcoin prices continue to be this high, ASIC companies will use the new technology to create new ASIC's. In this case, the network's hashrate will rise exponentially, the diff will rise, so the number 5949437371609 in the above formula rises exponentially, making it impossible to mine with new cellphones due to the high diff