I agree with the previous posters, but wanted to give you some more background info...
A cpu, GPU, fpga, old ASIC can
technically create sha256d hashes.
Basically, you need the block header of the previous valid block, you need the merkle tree of the transactions in your current block (the block you're trying to get into the blockchain), you need to be able to iterate over nonces and create a sha256d hash of the header of your own new block. If you find a sha256d hash of your new block's block header that's under the current target, your block is valid... and
TECHNICALLY, you can use pen and paper, a cpu, a gpu, an fpga, and old asic to do this...
TechnicallyPlease not that i used the word technically..
There's a nice article on the bitcoin wiki:
https://en.bitcoin.it/wiki/Non-specialized_hardware_comparisonIf you're asking about mining with a cellphone, the benchmark puts you in the "less than 1.000.000 hashes per second" category (<1Mh/s).
If you look at the current hashrate chart:
https://www.coinwarz.com/mining/bitcoin/hashrate-chart you'll see that the current estimated hashrate is around 1 ZH/s.
1 ZettaHash = 1.000.000.000.000.000 MegaHash
This means that your cellphone would have one chance in 1.000.000.000.000.000 to solve the current block because your cellphone has about 1/1.000.000.000.000.000 of the network's estimated hashrate...
This looks "feasible" because people are notoriously bad when it comes to interpreting large numbers...
I looked at the powerball odds, those are one in 292.200.000 to win the jackpot... It's about 3,5 million times more plausible to win the powerball lottery jackpot than it is to find a valid block with your cellphone... Even if the average time between blocks is ~10 minutes and powerball draws seems to be once every two days, it's still 11.833 times more plausible to win the current powerball jackpot than to solve any block in the time between two powerball draws... AND, if you win powerball, it seems to be a multi million dollar jackpot vs solving a block for ~300k... I did not calculate the cost of running a cellphone cpu, but i'm pretty sure it would be more or less on par with a powerball ticket (since you'd need a cellphone specifically for mining, so you could not use it for other tasks, you'd also need power for your cellphone, cables, chargers... and you'd need network equipment or a mobile subscription to mine...).
Now, i'm not a gambling man myself... But if i had to chose between buying a lottery ticket and mining with my cellphone, the math is pretty clear... It's thousands of times more probable to "win" with a lottery ticket, and the lottery pays out hundreds of times more than solving a block... It's a no-brainer...
The main problem with cellphones is their cost per hash, both in hardware and power cost... They are simply to expensive to buy, store, maintain and they are to inefficient in creating sha256d hashes... If you would buy up 1.000.000.000 old cellphones and let them mine, you'd have a one in a million chance to solve the next block, but you'd need a huge warehouse and a lot of staff to store those phones, and they would burn so much electricity you'd probably have to build your own nuclear power plant to have enough electricity (i did not do the actual calculations)