Just because I'm a whore for my little project: My puny little FPGA miners will remain profitable until the difficulty reaches ~4,000,000, assuming 1BTC = $1USD and $.15 per kWh. Go ahead, check my math:

80MHash@5Watts
5 W * 24hr => 0.12 kWh/day
0.12 kWh/day * $0.15/kWh => $0.018/day
50 BTC / x days => BTC/day; Need 0.018 BTC/day assuming 1BTC=1USD
50 BTC / 2777 days = ~0.018 BTC/day (profitable)

4000000 Difficulty @ 80MHash/s = Average 2485 days for payout

 

Is there a place to get the difficulty history? The site linked from the wiki, http://nullvoid.org/bitcoin/difficultiez.php, appears to be down at the moment.

Also, specifically for the poll, do you mean to include the capital cost (cost of buying the cards)? For example, if you already own your cards and don't care about getting your money back on them, then they will be profitable as long as they generate more than the maintenance costs. That will likely persist for quite a bit longer than the same figures after factoring in capital costs.

I don't personally enjoy the type of elitist segregation that a "pro zone" implies, especially on a project that purposefully puts us all as equals.

We already have the Development & Technical Discussion sub-forum. Is that not good enough? Mods are free to move irrelevant threads out of that sub-forum and into Bitcoin Discussion or Technical Support.

Please read:
How are new Bitcoins created?

Specifically:


And to answer your other question:
Sure; if you had 90% of the money in the world, you could buy up 90% of the computing power and get 90% of the Bitcoins. So ... you'd have the same proportion of Bitcoins as you do real world money. Seems reasonable.

Computers cost money, so having the most power computers equates roughly to having the most money. So, why shouldn't those who invest heavily in mining reap a proportional reward?

And having the most Bitcoins doesn't help you. The value of those Bitcoins is dictated by those willing to accept them, not by the person with the most Bitcoins.

Ummm ... I realize you just started this site, so maybe it's a bit too early for criticism ... but the site and your post don't explain what this is. All anything says is that you want donations, without explaining what the site is. That seems a little ... backwards.

www.fpga4fun.com

You can build simple designs and test them in a free copy of ModelSim without owning a real FPGA. Small FPGAs dev kits are very cheap these days. There's a Cyclone 4 kit out there for $80 USD ($60 for academic).

Altera's Cyclone III EP3C120F780, from the Cyclone III FPGA Development Kit.

The design will also run just fine on a Cyclone IV C115, which is a bit cheaper.

Well, I've been occasionally poking and prodding my design. The pipelined version is clocking at 80MHz now, and down to 80K LEs (64K being the goal, down from 90K). Not huge progress, but I figured I'd keep the thread alive.

I took a break from my FPGA miner to throw together a JavaScript miner, mostly for educational purposes. It's on GitHub:
Bitcoin-JavaScript-Miner

If you upload it to a server, it functions. My system gets about 8khash/s, which is just cute  but that's actually a bit more than I expected.
It hasn't been tested for accuracy, so for all I know there's a bunch of bugs in the hashing code.
It doesn't do a real getwork, nor does it submit work (if it ever actually finds a share ...)

But I commented the code, and tried to make it as clear as possible. The real grunt work is in miner.js, so look there if you want to know how Bitcoins are mined.
work-manager.js is where miner.js is called from. Since a real getwork isn't actually used, there isn't much to see there. Normally it would talk to a mining pool server, and do a "getwork" request, which gives you the information you need to execute the code in miner.js. Once a valid hash is found, that would be returned to the mining pool server.


Enjoy! If I have the motivation and time I'll see what I can do to A) make sure it's bug free, and B) make it work with an actual mining pool ... just for giggles.

If you guys are interested in my work, let me know, and I'll continue to post updates and such. Otherwise, I guess I'll just toil away in silence.

And a quick note:
The current design uses my PC to fetch work, and push it to the FPGA, as well as check for "Golden Tickets" (my funny internal name for valid nonces) and submit them when found. There's room in the pipelined design to put in a NIOS microprocessor. This could potentially use the ethernet port on the dev kit to do all the fetching and submitting. That way it'd be totally automated, and headless. 

  Wow, this is such a coincidence! I was just browsing the forums tonight, and stumbled upon this thread. I finally registered an account just to post in this thread.

I've been working on an FPGA miner for the past few weeks! It's fully working*, currently running on my desk in front of me and generating up some tasty shares I'll give an overview of my work:

Current Performance
Device: Altera Cyclone 3 C120 Dev Kit
Performance: 70Mhash/s
Power: 2.26W
Efficiency: 30.9 Mhash/W


It's written in Verilog, all crafted painstakingly by hand. There are two alternative designs. One is a serial design composed of many SHA256 cores running in parallel, each core computing a hash in 64 cycles (2 cores needed for the full hash). Each full core (2 half cores) consumes about 2800 LEs. The second design (currently running in front of me) is a pipelined version with one LOOOOONNNNGGGG chain of hashing stages running in parallel. That design computes 1 full hash every clock cycle. It runs at a maximum of 70MHz right now. Actually, I haven't tried pushing it to its limit, so it may very well run much faster. I'm hoping for 100MHz.

These are my results after off-and-on work for a few weeks. I've actually put most of my efforts into the serial design, because the pipelined design takes at least an hour to synthesize each time. The serial design can currently fit 42 full cores into the C120, each running at 90MHz and computing a full hash every 64 cycles. That's about 59Mhash/s.

The latest revision of the pipelined design consumes 90,000 LEs, so it's pretty big. I'm working to cram it into <64,000LEs so I can get two of them in one C120 chip, and push their clock to 100MHz, giving me a whopping 200Mhash/s.

I haven't used the on-board power meter before, but if I'm reading it correctly the FPGA is currently using 2.26 Watts. That ... seems really low, but Altera's website verifies that that's actually above average for a C120, so I guess it's accurate. That's 31 Mhash/W, which is 1200% more efficient than the most efficient GPU listed on the Wiki. So efficient, it's basically free. Poor guy runs terribly hot though. I need to go put a fan on him...

The only downside is that this board in particular, the C120, costs $1000. The same design will easily fit into the DE2-115 board (from Terasic), which only costs $600. I have one of those too, so I'll test on him later. You're not likely to pay off that $600 quickly, though, so I guess it isn't economical yet. A reduced version may run in the DE0-Nano board, which is $80, but obviously it won't have the same performance (about 25%).

All my efforts are put into optimizing every last bit of the design, so we'll see how far I push the poor FPGA. It already out-performs my GTX 285 card, so I'm happy  and at a fraction of the power cost.

And I'm only getting started  Who wants to front the money to buy me a Stratix board and move this into Hardcopy? 

* By fully working, I really do mean it. It's happily submitting hashes to a pool. I was quite thrilled when my little baby submitted his first share