- One String - a novel bitfury miner design -

[sidehack]

Oh, so the cost savings is in the parts list, not the actual power supply. The only reason i asked is that i'm getting tired of miners requiring ATX power supplies. Unless you get a modular one you have to deal with a bunch of unneeded cables. also they take up more room than a power brick. Unless you use some sort of case to put your miner in, your work space can become quite messy/unwieldy. This is one of the reasons i won't buy ASICminer Cubes, 1-2 Cubes per powersupply can make for a lot of power supplies laying around. I'm a Hobbyist.

In the next day or two I should have prototype information available for an interface board designed to break out server supplies for use with miners; these can typically be found for much cheaper than an equivalent output/efficiency ATX supply and usually exhibit better regulation. Screw terminals so you only use what wires you want, and additional output filtering. They're also designed to be run in parallel with load sharing and daisy-chain for automatic power-on in groups.

The problem with this design is that it requires the 12V power supply to be very well regulated (and adjustable if you want to overclock). Normal ATX PSUs are not that well regulated (ATX spec provides for up to +-5% tolerance on the 12V line (older spec allowed 10%).

If enough people want it, I'll look into adding a trimmer to tweak output voltages.


Been watching this thread; series power dropping chips (if it can be done reliably) is such a darn cool idea and if someone ends up making these boards affordably (and chips are available for not a bajillion dollars) I'll definitely be in the market. Good work, guys.

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[Taugeran]

So, now it's time for you to design board with parallel/serial connection of chips
PowerMatrix

We did that already. It's called X-HASH:)

intron

and how did that work?

It takes so many bitfury chips to test it, we were
reluctant to try it. That's why we started with the
smaller strings.

intron

are there any photographs available of said x-hash or was one ever fabbed?

[intron]

So, now it's time for you to design board with parallel/serial connection of chips
PowerMatrix

We did that already. It's called X-HASH:)

intron

and how did that work?

It takes so many bitfury chips to test it, we were
reluctant to try it. That's why we started with the
smaller strings.

intron

are there any photographs available of said x-hash or was one ever fabbed?

No, the board was only designed, never made (yet).
As I mentioned, we didn't want to risk a lot of bitfury
chips for just one experiment.

intron

[Pentium100]

In the next day or two I should have prototype information available for an interface board designed to break out server supplies for use with miners; these can typically be found for much cheaper than an equivalent output/efficiency ATX supply and usually exhibit better regulation. Screw terminals so you only use what wires you want, and additional output filtering. They're also designed to be run in parallel with load sharing and daisy-chain for automatic power-on in groups.

I have repaired a couple of power supplies used in Supermicro servers (Ablecom forgot the part number). While I still do not know the full pinout of the connector, I found which two traces to short inside to turn it on. Aslong as the power supply is not fully digital, it should not be difficult to use it. Still, the regular ATX PSUs are simpler and easier to fix

If enough people want it, I'll look into adding a trimmer to tweak output voltages.

Traditional (not digital) power supplies can be modified to adjust he output voltage just by controlling the feedback. However, if you want the adjustment to be external to the power supply (so you don't need to open the PSU), then youwill have to use a powerful regulator and the total cost will probably be higher than an adjustable PSU.

[intron]

Had five Ones String boards hashing for some
time, performance looks nice and stable and
no thermal runaways.



intron

[KNK]

No, the board was only designed, never made (yet).
As I mentioned, we didn't want to risk a lot of bitfury
chips for just one experiment.

I don't think it will work better than several strings in paralel. The chip seems to like constant current more than constant voltage, but the built in regulator will try to equalize the voltage across paraleled chips and if they are not equal, they will not perform at their best ... and you save nothing more than few resistors on the SPI. I have my strings running on 24V better than on 12V, probably because the current is more stable

I hope the chips will be cheap and freely available in volume soon - my idea is to run the string directly on 220V, which also risks a lot of chips for the experiment, but will save additional 10-20% of power efficiency ... just not sure if RPi will be capable of running 350-400 chips in a string and also there is the lower SPI speed with the increased string length

[intron]

No, the board was only designed, never made (yet).
As I mentioned, we didn't want to risk a lot of bitfury
chips for just one experiment.

I don't think it will work better than several strings in paralel. The chip seems to like constant current more than constant voltage, but the built in regulator will try to equalize the voltage across paraleled chips and if they are not equal, they will not perform at their best ... and you save nothing more than few resistors on the SPI. I have my strings running on 24V better than on 12V, probably because the current is more stable

I hope the chips will be cheap and freely available in volume soon - my idea is to run the string directly on 220V, which also risks a lot of chips for the experiment, but will save additional 10-20% of power efficiency ... just not sure if RPi will be capable of running 350-400 chips in a string and also there is the lower SPI speed with the increased string length

Did you try placing chips in parallel? I'm also not
sure whether to make seperate strings or connect
all nodes with the same voltage level together.
Biggest challenge is the huge amount of chips you
have to sacrifice for a single experiment that might
run haywire:)

And this 220V string is af course the optimum you
can get in cost efficency:) Looked into a rectifier
for this, it's not easy, mainly due to the current that
is needed.

[KNK]

Did you try placing chips in parallel?

Didn't even tried that. During my tests i have discovered that each chip requires a bit different voltage for optimal speed, but always the same amps, so it's like the chip 'wants' to be serially connected

And this 220V string is af course the optimum you
can get in cost efficency:) Looked into a rectifier
for this, it's not easy, mainly due to the current that
is needed.

You need 2-2.5A for the string ... let's make them 3A = 600uF for 0.1V @50Hz it's not that much and expensive, but still, the main ripple regulator should be the current limiter for the string and then each chip for itself (via it's current mirror)

One of the problems is that the grid voltage is not so stable, you need protection from the (kA) spikes, so you will definitely need an UPS (and if it's on-line model with 220V to 110V conversion, you can go with shorter strings), but then you'll loose in efficiency again
The second one is, the string length will reduce the SPI speed and the third one is that RPi (or dedicated MCU) may not be able to drive that much chips

EDIT: Ooops it's 300mF not 600uF, so you are right it will be expensive

[VinCeCream]

Had five Ones String boards hashing for some
time, performance looks nice and stable and
no thermal runaways.



intron

Well done folks !

[pauljbl]

Hi

Are you able to make me this miner if I get the chips

Cheers

[intron]

Hi

Are you able to make me this miner if I get the chips

Cheers

https://bitcointalk.org/index.php?topic=370932.msg3963420#msg3963420

[intron]

Fastest USB miner at this moment:





Doing 15+ GH sustained, hex•fury is running
from a 5.5 Volts supply.

intron

[RoadStress]

Fastest USB miner at this moment:

Doing 15+ GH sustained, hex•fury is running
from a 5.5 Volts supply.

intron

How much?

[intron]

Fastest USB miner at this moment:

Doing 15+ GH sustained, hex•fury is running
from a 5.5 Volts supply.

intron

How much?

PM-ed you.

[KNK]

Fastest USB miner at this moment
...
from a 5.5 Volts supply.

So it's not powered from the USB, but from an external power supply ?

Even at the minimum 0.6W/Gh the BF chips are capable of - 15Gh is 9W, which is not possible from a single USB port be it even 3.0
With 2x USB 3.0 or 4x USB 2.0 it is doable

[klondike_bar]

nice USb, but i dont understand why - it draws far too much power for a USB port, so for the effort of getting it to work it seems like a much easier idea to go with the one-string or other design that uses 12V and holds more chips

[pgminer01]

please pm the price for hex fury , thanks

[intron]

nice USb, but i dont understand why - it draws far too much power for a USB port, so for the effort of getting it to work it seems like a much easier idea to go with the one-string or other design that uses 12V and holds more chips

It takes about 2.5 Amps, you can power it from
an USB hub. And it also has a seperate power
input that feeds the bitfury ASICs. When this
option is chosen then the USB has to power
only the processor.

And indeed, we were just playing around a bit...

[libertybuck]

Hi intron, please PM me price for hex-fury. 

[goxed]

nice USb, but i dont understand why - it draws far too much power for a USB port, so for the effort of getting it to work it seems like a much easier idea to go with the one-string or other design that uses 12V and holds more chips

It takes about 2.5 Amps, you can power it from
an USB hub. And it also has a seperate power
input that feeds the bitfury ASICs. When this
option is chosen then the USB has to power
only the processor.

And indeed, we were just playing around a bit...

Extremely promising design. Congrats what is the controller chip that you are using? Thanks!