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1  Economy / Marketplace / PHP script accept small payments on site (ie. for shares) on: May 28, 2014, 06:15:20 AM
Is there a very simple PHP script to accept payments on a web site?

The scenario would be that there is a web site that says two items are available.

Item A: 0.001 BTC
Item B: 0.002 BTC

User gets to select the item and the quantity, gets a total and maybe a qrcode where to send the coins to.

Since user is logged in with email address, the trade is logged in the database with his email and that's about it.

If it doesn't exist, I am looking for somebody to do this and I am willing to pay a bit of money for it.

I don't have a problem making it open source.

Could be a bit more complex with the site displaying payment status to that address, or other quirks, but that can be added on top later.

Perfect would also be if the data is not stored locally (ie. MySQL), but instead on a Google Spreadsheet or other Google doc. When the web site goes down, the data would still be there Wink

The script would also check status of the payment and then make a record once paid and confirmed.

2  Bitcoin / Mining / White Paper: Analysis of Large-Scale Bitcoin Mining Operations on: March 27, 2014, 12:03:26 PM
Here's a new white paper about large scale mining ops and immersion cooling.

White Paper: Analysis of Large-Scale Bitcoin Mining Operations

3  Economy / Computer hardware / [WTS] 100X PSU Cooler Master Silent Pro M 850W (Location: Hong Kong) on: March 16, 2014, 01:42:34 PM
Cheap Wink (what are they worth?)

I have around 100 of these. They have a 3 or 4 years warranty from Cooler Master and they sit here in my warehouse in Hong Kong (purchased from official distributor).
There is no packing but they are all nicely stacked away in plastic containers (6 in a box if I remember correctly).

Preferably looking for a local buyer in Hong Kong.
If you are not in Hong Kong, shipping will be rather complicated and I'll need at least a week or two to get them out the door (need to buy packing material and other stuff).

Cooler Master Silent Pro M2 850W
RS850-SPM2D3-US; RS-850-SPM2

They are 12V single rail.

Other Specs
Model    RS850-SPM2D3-US; RS-850-SPM2
Type    Intel Form Factor ATX 12V V2.3
Dimension    150 x 180 x 86mm
5.9 x 7.1 x 3.4 inch
Input Voltage    90-264Vac (Auto Range)
Input Current    11 5.5A
Input Frequency Range    47 - 63Hz
PFC    Active PFC (>0.9)
Power Good Signal    100-500ms
Hold Up Time    >17ms
Efficiency    80 Plus Silver
MTBF    100,000 Hours
Output Capacity    850W
Operation Temperature    0~40C (Nominal Input Voltage)
Regulatory    TUV / CE / UL / FCC / BSMI / GOST / C-tick / KC / CCC
Fan    135mm Hydraulic Dynamic Bearings
Certification    80 Plus Silver
Connector    M/B 24 Pin Connector x 1
CPU 8 Pin x 2
PCI-E 8 Pin x 3
PCI-E 6+2 Pin x 3
SATA x 12
4 Pin Peripheral x 5
4 Pin Floppy x 1
Warranty    5 years
UPC Code    884102014543

4  Bitcoin / Mining / The World's Largest Mining Farms on: March 15, 2014, 12:32:53 AM
I am compiling a list of the largest known Bitcoin clusters in the world.

** this list is now outdated **

I start with the following, but I am sure that's just a few of them. We should probably also include the cloud hashing companies.

Name: KNC Data Centre
Capacity: 10 MW
Location: Boden, Sweden
Hardware: KNC Jupiter (and Neptune?)

Name: MegaBigPower
Capacity: 1.4MW
Location: Washington State
Hardware: Bitfury

Name:  CloudHashing Texas
Capacity: Huh kW
Location: Dallas, Texas
Hardware: Cointerra TerraMiner IV

Name: Asicminer (Immersion Cooling)
Capacity: 500kW
Location: Kwai Chung, Hong Kong
Hardware: Asicminer

Name:  CloudHashing Iceland
Capacity: Huh kW
Location: Reykjanesbaer, Iceland
Hardware: KNC?

Name: 's farm (seeksilence)
Capacity:  ~120kw (on 3/16) up to 800kw
Location:   China
Hardware:  1T 28nm JTminer

Name: Asicminer Original Farm 2
Capacity: 500kW
Location: Shenzhen, China
Hardware: Asicminer

Name: Gigavps
Capacity: 264kW
Location: USA
Hardware: Mixed (AntMiners etc)

Name:   IceDrill
Capacity:  250kW ??
Location: Montreal, Canada
Hardware: HashFast

Name: Asicminer Original Farm 1
Capacity:Huh kW
Location: China
Hardware: Asicminer

-- // --

Pending info, not enough details yet, PMs sent:


-- // --

If you have any info, please post in this thread. I can eventually updates this post with a total list.

Template to copy and paste:

Capacity: (kW or MW)

5  Other / Off-topic / USA credit check on person? on: March 11, 2014, 03:35:42 AM
Is there a reliably way to check a person in the USA, get a credit score, info if they are reliable, etc?

What info do you usually have to provide?
Name, address, phone numbers? birthdate?

Basically I am trying to find out if a potential client is really who he claims to be.

6  Bitcoin / Mining / Facilities with $0.02/kWh in Seattle or Washington State on: March 09, 2014, 08:46:49 AM
Can somebody please enlighten me how companies in Washington, or specifically in Seattle, are only paying $0.02/kWh for electricity?

Or is that just the unit of kWh, without demand charges etc?

Does this also scale, say 1MW, 2MW, 5MW etc?
7  Bitcoin / Press / Electronics Cooling: Bitcoin 2-Phase Immersion Cooling & Implications for HPC on: March 04, 2014, 03:48:34 AM
Electronics Cooling magazine has dedicated the cover of their march issue to Bitcoin  D

Bitcoin 2-Phase Immersion Cooling and the Implications for High Performance Computing

Page 24
Read the full march issue here:

8  Economy / Services / Solidworks freelancer wanted on: January 29, 2014, 09:24:19 AM
I am looking for a Solidworks freelancer who can work with me on a few simple designs in the next few days (while my usual "design engineer" is on a holiday trip to South Africa).

After initial back and forth via email/skype/chat or phone that will maybe take 1-3 hours, it might be a day or two of work, depending on how far we take it. It's basically a product idea, doesn't have to be production quality design.

If you have done something before, post some references or send me a PM please. Also post how much you charge.

We are actually always looking for freelancers, so this will be very useful for the future.

9  Economy / Services / [1 BTC for simple electronic circuit (PWM to tach signal with 555-timer IC) on: May 05, 2013, 02:29:09 AM
Ok I am sitting here in an urgent experiment, it's weekend and my electronic skills seem a bit rusty.

I have a PWM signal and need to generate a tach signal (open collector) from that. This is to simulate a fan.

Mainboard commands fan to run at X RPM via PWM signal. Mainboard reads back fan RPM via tach signal. Fan not present, mainboard complains. That's what I am trying to stop.

The fan has 4 wires.

12V (red), GND (black), PWM Control (brown), TACH Sig (white)

The fan speed is controlled by the PWM control wire (brown). Fan speed is duty cycle, so 50% means 50% fan speed. Max speed is 22,000 RPM.

Tach signal (white wire) is an open collector with two pulses per revolution.

At full speed we should have 44,000 pulses on the Tach signal, or 733 Hz.

The mainboard checks if the fan works, so using another fan or removing the fan altogether is not working. It also seems to check if the fan speed is anywhere near the commanded fan speed.

Here is the datasheet of the fan:

How would one build a very simple circuit that simulates the fan?

I imagine a small circuit that gets the PWM signal, and depending an duty cycle outputs the open collector pulses. ie. 0% duty cycle 0Hz, 100% duty cycle 733 Hz.

Don't tell me I have to use an Arduino or MCU, this must be possible with something very simple. I have access to lots of components (555 etc) and I plan to get this working within a day or two.

Help me with full instructions and a circuit diagram and 1 BTC is yours.


10  Economy / Computer hardware / Ztex 1.15y Quads (FPGA) for sale by the lot of 5+ on: April 19, 2013, 12:42:24 PM

I currently have quads for sale, by the lot of 5 pcs minimum. 850 MH/s average.

Please PM your offers (BTC) and I will ship them out after Wednesday next week.

They are a licensed production from Ztex and I had my first quad units up and running even before Ztex shipped their first quads last year. I basically bought the original PCBs from Ztex and had them made in a professional SMT production line. Check for my posts on the Ztex thread from when I built them:

I am in Hong Kong, but worldwide express shipping is no problem and I can send them as a "gift". I can also throw in some free USB hubs and USB cables, but this may drive up shipping costs. Shipping of 2.5 kg or around 5 lbs is below US$ 50 to the USA or Europe and should take less than a week. Heatsinks/fans are also included.

I am usually not selling stuff here the the forums, but I had already sold a couple of things including 5 Icarus boards and BFL singles a long time ago. Ask Kano or Cablez if you need a reference.

Only buy if you know what you are doing, I cannot give any mining support or help you get them up and running. But I guarantee that they work and I can throw in brand new fans and heatsinks (as bonus) in original packing if you want.
11  Other / CPU/GPU Bitcoin mining hardware / PSU Ampere Calculation (on the wall with 230V) ?? on: May 31, 2012, 10:51:20 PM
I am a bit puzzled again. Apologies if this has been answered before.

I am using 230V.

The PSU has 850W, I am currently using around 640W at the 12V rail. Lets assume for a moment I'd be drawing the complete 850W.

The PSU has 88% efficiency typical at this load (= 12% inefficiency).

850*1.12 = 952W.

At 230V that means the PSU should require a current of 4.14A (952/230). Why does the PSU say the following on the box:

AC Input:  100-240V~ 11-5.5A  60-50Hz

I know it's 240V not 230V, but 10V difference make 1.36A???

How am I supposed to estimate how much power it draws, how many of them I can connect to a single 13A or 16A outlet, etc? If I go by the 5.5A number, I can only connect two PSUs :/

Does anybody feel like teaching a dork like me some basic electrical skills?
12  Bitcoin / Hardware / FPGA Cluster using Atom Board on: April 06, 2012, 11:36:42 AM
Is anybody here using Atom boards to run their FPGA cluster?

What is a typical power consumption of Atom boards with minimum specs (CPU + memory + flash drive)?

Can the same ATX PSU be used to power the Atom boards (what input do they use) and the FPGA boards (I've been using an ATX PSU for my Icarus + Ztex setup).

I am totally new to Atom boards. But I guess it's a good approach for running a small to medium cluster, isn't it? What other options (except stuff like Rasperry Pi) are there for off-the-shelf hardware?

I'd like to have one of the smaller form factor Atom board that is still powerful enough to run 30+ FPGA boards (I only have a few now, but hopefully more sooner or later). Any idea which ones I should look at?
13  Bitcoin / Hardware / For devs - electronic test equipment up for grabs on: April 05, 2012, 12:58:48 AM
I am posting this here because we have a few hardware developers here. There is a company that is going out of business in my neighborhood.

I personally probably couldn't use anything else than the power supplies and voltage regulators, but I honestly have no idea what the rest of this stuff is/does. The guy in charge of liquidation told me I could have it for cheap and I have already bought their network equipment for a few dollars each server/Firewall/etc since this is exactly what I needed for a new office/server room. He mentioned $150 for each unit, but I am sure I can get him down to 1/3 of that since I don't think many people are interested in any of this.

There are more photos in the Picasa album.

Have a look in the original thread and reply over there please.

It's probably all old crap. The company looked quite old. The equipment is all in a small metal office/box to limit electronic noise from outside I suppose.

14  Other / Off-topic / Electronic test instruments for grabs on: April 05, 2012, 12:49:53 AM
I've been offered all this for a few dollars.

I personally probably couldn't use anything else than the power supplies and voltage regulators, but I honestly have no idea what the rest of this stuff is/does. The guy in charge of liquidation told me I could have it for cheap and I have already bought their network equipment for a few dollars each server/Firewall/etc since this is exactly what I needed for a new office/server room. He mentioned $150 for each unit, but I am sure I can get him down to 1/3 of that since I don't think many people are interested in any of this. I am not looking into reselling, unless someone here convinces me it's something they really want/need and I can safely ship it from here in Hong Kong to wherever you are (will be a nightmare and costly but doable).

Does anybody recognize anything here?

Seems they were in the business of developing some kind of AM/FM stuff, but some of the equipment looks useful (Oscilloscope, power supplies, etc).

Anyway, here is the album link with more photos and other equipment:

15  Economy / Economics / Real transations vs. miners/pools/speculators? on: March 28, 2012, 11:54:48 PM
From BitcoinWatch/BitCoin Charts:

Transactions last 24h:            7,150
Transactions avg. per hour:     297.92
Bitcoins sent last 24h:            685,817.55 BTC
Bitcoins sent avg. per hour:     28,575.73 BTC

I wouldn't be surprised if a large portion of this is made up by miners/pools/speculators, another larger portion by Silk Road, and the rest (people actually paying for their goods/services) would be a very small portion. Like a hand full of transactions.

Has there been any "research" of the size of the real Bitcoin economy, excluding the miners, pools, speculative trades on exchanges, etc?

The list of places acceping BitCoin is growing, but based on the numbers above it looks to me like they are not getting a lot of business at this moment.
16  Economy / Economics / MtGox Income on Fees US$ 91,098 to US$ 218,635 for 3 months? on: March 24, 2012, 06:38:20 AM
I am fairly new to Bitcoin and I am just trying to figure out if I am overlooking something.

MtGox seems to be the biggest BTC exchange.

According to Bitcoin Charts, the trading volume during the past 3 months on MtGoxUSD was 7786162.18 BTC.

MtGox takes between 0.25% and 0.60% trading fee. I assume that's from both parties involved (buyer and the seller). Makes between 0.50% and 1.2%.

Given the volume above, that means MtGox earned somewhere between BTC 19465 (US$ 91098) and BTC 46716 (US$ 218635) in the past 3 months. By today's MtGoxUSD rate ($4.68/BTC) anyway, I am aware there are fluctuations.

Did I understand that correct?
17  Bitcoin / Hardware / Water Cooling for large FPGA mining cluster (hundreds of FPGAs) on: March 15, 2012, 05:23:24 AM
Would it be feasible and affordable to do water cooling on a large FPGA mining cluster with hundreds of FPGA chips instead of AC and airflow cooling?

For instance each radiator (that's what they are called, right?) could be covering 4 FPGA chips. As you can probably tell, I have no idea about water cooling and I have no idea if stock equipment is available that could be used.

But if FPGA prices come down, and somebody is going to build a larger cluster of hundreds or thousands of boards, they will eventually run into cooling problems.

Say you are building a rig box equivalent of 50.4 GH/s, that means you already have around 250 FPGA right there.
18  Bitcoin / Development & Technical Discussion / Date for 25 BTC per Block on: March 03, 2012, 01:57:56 PM
This has probably been discussed a lot of times, but I just can't find the right answer.

What is the estimated date that the block reward changes to 25 BTC?

From the Wiki:

The coin value of a block is 50 BTC for each of the first 210,000 blocks, 25 BTC for the next 210,000 blocks, then 12.5 BTC, 6.25 BTC and so on.
19  Other / CPU/GPU Bitcoin mining hardware / LargeCoin, what is that? on: February 01, 2012, 04:02:19 AM
I just read an article about GPU mining over at (Google translation) and they were talking about LargeCoin.

Can anyone give me a quick rundown what that is supposed to be? I found a web site, a bit of bash here on the forum, but I still don't get it.

20  Economy / Trading Discussion / Accepting Bitcoin on eCommerce site? on: January 31, 2012, 10:06:21 AM
Is there a payment processor (just like PayPal) that lets my eCommerce site accept BitCoin payment and gives me US$ or any other "real" money?

I am not looking for a plugin or program to do that (but I am still happy about pointers in that direction), I am looking for a all-in-one solution. Basically just like setting up PayPal or Credit Card for my web site, so that the customer can pay in BitCoin through my site, and once the transaction is done my account shows a credit of X BitCoin or Y USD equivalent (daily course basically).

I hope I didn't describe what I am looking for too complicated. Basically all I want to do is accept BitCoin, but without the "hassle" of having BitCoin and them having to take care of selling them for money frequently, monitoring the exchange value, etc etc... (I understand that this is very easy, but unfortunately I'd need cash as soon as possible in order to pay bills etc).
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