You're posting in the general forum, so i'll be talking about BITCOIN mining.
An rPi3 has
cpu: 4× ARM Cortex-A53, 1.2GHz
gpu: Broadcom VideoCore IV
There are no benchmarks for these kinds of cpu's, but if you visit my profit calculator site:
http://www.mocacinno.com/mining/We can say that:
- at current diff, the "best" mobile cpu's (on average) mine ~0,00000002
BTC/year (mining 24/7). Since an ARM cortex is not comparable to an intel atom, the real "profit" is probably a lot less
- there are no benchmarks whatsover for mobile gpu's (since nobody mines with them), but it's very hard to see them top an Nvidia Quadro NVS 135M. So the net "profit" would also be a lot less than ~0,00000002
BTC/year
So, if you run an rPi3 on a pool and you run at full cpu and gpu load, you'll probably "earn" less than 4 satoshi's per year...
the minimum withdrawal fee of most pools is > 0.001
BTC... So you'd need to run 5000 rPi3's at 100% load (cpu+gpu) for a full year in order to reach the bare minimum withdrawal limit. I overestimated the hasrate of both the cpu and gpu, so it'll probably be even worse than this.
Conclusion: you'll need to spend thousands and thousands of dollars in hardware and energy to make $3.6/year, the diff is sooooo high, that most pool's minimum diff for a valid share is allmost impossible to hit with a mobile cpu or gpu... In other words: if you run a cpu miner on an rPi, it'll look like nothing is happening... Maybe once
every couple of days a year, you *might* see a single share being submitted (if you're lucky), but that's about it.
If you want to mine just for fun, and see the shares running in and at least register on the pool's dashboard, have a look at sidehacks projects...
You'll never ROI, but at least the pool will acknoledge you're mining with them (and they only cost a couple of bucks, so they're a nice learning tool or conversation piece...). For example, a 2Pac will make ~0,00040976/year drawing 14 Watt, you only need 3 of those sticks to be able to withdraw your "profit" after a year (in case the diff doesn't skyrocket).
Now, this was only about BITCOIN mining. There *might* be some ALTcoins that are minable on a mobile CPU (altough i doubt it'll be profitable or fun to watch).
EDIT: after i saved this post, i realised you would not hit a share every couple of days with that hashrate at current diff... If you're lucky you might hit a share a couple times a year... So i edited the post with a more realistic prediction
