Soldered in all the through hole components, programmed the EEPROM that defines the hub functionality, installed the board and finished the power wiring. Now for a quick power test before plugging the VIM3 boards in - expensive to blow them up!
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Did the power supply work? 
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power works but the usb hub bit isnt working - i think ive missed out some resistors from the CC1 line that i didnt thnk about because i hadnt used USB C before and hadnt read enough of the spec! Think i need a 5k1 pull down on the downstream ports and a 56k pull up on the upstream port.
Have ordered them and an adaptor cable that i can solder the resistors onto to test as i didnt bring the CC pins out from under the connector on the PCB. If thats it then i need a new revision of my PCB with them on - annoying but if thats the only bit that doesnt work then i am quite pleased! Wish i knew someone that knew more about USB C to review my design to make sure i havent missed anything else off!
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What about GPU mining ? Mentioned above sgminer-arm has outdated algorithms, and most other GPU miners requires AMD drivers to work.
Does anyone know arm capable GPU miner with lets say lyra2re3, x16 or some other ASIC-proof algo support ?
I’ve gotten it working, The VIM 3 puts down 35H/s on CN-Pico
The VIM 3L puts down 45H/s on CN-Pico.
This was using the XMRIGv5+
How to make it work
$ sudo apt-get install -y mesa-opencl-icd ocl-icd-opencl-dev clinfo
$ sudo nano /etc/OpenCL/vendors/mesa.icd
replace the exsisting line with, libmali.so
$ sudo reboot now
in the config.json file for xmrig
under the the OpenCL section change the platform option to ARM
You’ll ned to modify the algo settings for the OpenCL setting mainly intensity, and worksize they are setup for AMD GPU’s.
I’ve not found other miner application that work with this yet. If we got vulkan support going then we would have more options to try. Enjoy
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You’ve got a nice build but you don’t need to use anything other than 12v the boards support up to 20v, power efficiency is affected but it’s still over 90%, It should help with the power problems your having since you’ll only need one source, with the fan control you can use the PWM pinout to control it, make sure to pick the board that runs the hottest.
Thanks! Power works ok, it’s usb Comms that isn’t going so well. Suspect it’s my PCB that’s not working - need pull-up and pull-down resistors on the cc lines. New board in the works. Using more than 5v would require implementating the usb c power delivery which is way more complicated than I wanted to make it - currently on a usb 2 hub chip. Can’t just plug it into 20v it negotiates up from 5v
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Having done another revision of the board and gone down to 4 ports to get the deisgn going Ive got the first bit working! Now have a VIM3 that recognises that it is attached to a USB2.0 hub - so pleased to see that output appear! Will get on the other ports tomorrow and hopefully it all works!
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Finally got this working - now have my VIM3 boards working on my custom backplane board - just plug in via the USB connector for power and ethernet over USB - great to see those ping results!
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5 VIM3 boards getting power and network over a custom backplane board for use in (mining) clusters. Individual power control for each of the 4 slave ports, including current monitoring - talk via I2C to the host board - cable over the top of the boards. Step up circuit to power 12v case fan (white header on top edge of the board) for cooling to remove second power supply in this video. Mains current monitoring via the two terminals on the top left
Will be publishing the designs when ive tided them all up. If there is interest could put together kits / populated PCBs.
Am hosting a webserver on the main board to give the whole unit a nice interface rather than low level I2C commands needed currently - working on the webpage for this now
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Have been working on the web frontend for my miner for the last few hours - learning flask and getting this going. Have got live current consumption measurements working - impressed with flask
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Integrated the rest of the power consumption information that can be had from the backplane board and made it look pretty using bootstrap
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Neat! I’ll be sure to post it to social media.
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Welcome to do it when its finished - will get some decent photos taken of it for you
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Depends on the coin tbh - for instance zillion coin is ~115kh/s whereas something like verium is around 750h/m. Those are per board so can just multiply by the number of boards it’s built out to. Need to get me a 4gb board to rest out some of the randomx variants.
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And what is the profit you are making out of this mining rig, are you getting anything as profit, I heard that, many of the mainstream cryptocurrencies we being obliterated by ASIC miners and other things ?
is that the same here ?
The answer is “it depends” im afraid - most of the established coins you wont make much profit on. The best place to do that is speculatively mining a coin that is realatively new - for example Xiro i made ~£200 mining that in a month or so - but that is a great example, most coins you speculatively mine end up worthless, but the game is hitting enough of them that you make money. All my rigs have been paid off with this approach. If BTC heads back up becuase of the halving then I expect profits will increase. The ROI for a rig is probably someting in the order of 18months at the moment - but this is the advantage of SBC - they stay profitable for longer as have lower electricity usage and there is also a decent resale value for them on eBay etc. if a better model comes along.
On ASICs - coins that use mainstream algorithms get hit by ASICs and FPGAs - but thats one of the reasons i moved to CPU only coins (or at least where there is parity with GPUs etc.). These coins can and do update their algorithms regularly and dont have the volume to make an ROI for either an ASIC or FPGA. See zettelkasten for example - that coin has an auto adapting alogirthm that changes over time.
By way of an example of profits for not spec mining and why its a bad idea - Zillioncoin (bottom of what is profitable to mine):
VIM3 is ~115kh/s, overall network hashrate is ~18.8Mh/s - which gives a VIM3 a 0.061% of network hashrate. On Zillioncoin the block reward is currently ~42.44ZLN and the blocks are spaced at 1 minute, so there are 1440 blocks per day, or 61113.6ZLN created per day. One VIM3 will get 0.061% (over a statistically significant period as this is all probability based) or 32.28ZLN per day. The proce of one ZLN is currently 8sat or 0.00000008BTC, so can expect to make 258sat per day or £0.0191 per day gross profit. Then taking off electricity - a board mining uses 984mA @ 5.08V which is ~5W. Ive got a average £0.13/kWh electric cost so mining for 24hrs costs 0.13*0.005=£0.0156. That gives a net profit of £0.0035 per day. This is why its important to pick your coin and why SBC are good - most desktops couldnt mine this at a profit but SBC can (even if it is a tiny one!). The important thing is to work out when to sell coins as well as just looking at the ZLN price for the last month it has gone from 8sat to 22sat which is clearly a big difference in price and the BTC price has gone up and down a lot as well.
Having said there there is also the potential upside to coins like zillioncoin - where the developer has a vision and is sticking to it. If you can mine at a marginal profit and think the coin might go up significantly in the future then this is also a form of speculative mining that doesnt cost money to do (you can pay for your electric).
All it takes is for one of these coins to take off and if you have a decent pile of the coin you can make your money back. Suffice to say that i havent put any new £ into this hobby for a long time - its paid for itself
Anyway thats probably enough on mining as this is quite a wall of text - sorry!
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Thanks @birty
quite useful data, I learned about cryptocurrency mining a long time ago probably (2010-2011), but I was a wee little boy back then, and my father wouldn’t trust giving me a computer do something like that, Now both of us regret Not being able to make money that easy for a small investment back then,
but he is still skeptical about cryptocurrencies, but anyway thanks for letting me Know
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Nowadays for many people stealing cryptocurrency is more profitable than mining it, so it is important to keep those private keys and wallet addresses safe, happy Mining 