The True Hackers

A quote of the day for me comes from a digest of the Gemini project software history (

“I’m beginning to learn things about the Gemini memory I wish I had known in the 1960s. For example, after many divide instructions were executed in a row (I don’t know how many), the memory cores heated up and you would get the wrong answer in the accumulator. This problem was controlled by inserting a no-op instruction between the divides, thus keeping the cores cool enough to always give the right answer. Wow!”

Wow! indeed..!

Testing equipment at Hackerspace Kraków

Hackerspace Kraków got two nice analog oscilloscopes with 20MHz bandwidth from our sponsor. Initial tests using the built-in 1kHz square wave generators with provided probes showed a gloomy picture of bumpy squares that could have been caused by Who Knows What, and the picture below shows the best we could get by tuning the probes.


Yesterday I brought my cheap Voltcraft/Hantek/Tekway DSO to see what’s going on. Turns out the main problem were our probes – using the ones from my oscilloscope we got nice squares using all three signal generators available!



However, testing revealed that test signals provided by generators in HS oscillosopes are not 1kHz squares anymore:



And this one is quite disturbing as well – given the same signal source – I hope it’s just the matter of using two completely different probes!


Paradigms of programming

An example of object-oriented programming from one of universities:

public class Hello {
        public static void main(String[] args) {
          System.out.println("Hello, I am James B.");


Scharfes S in English

I’m writing this to share a curiosity I’ve stumbled upon a minute ago, one that I wasn’t aware of before. It turns out scharfes s (ß, better known from German) was in use at least around 17th century! See how the Royal Society was addreßed ;) in this piece.

Disabling PayWave

A short follow-up to my previous post about disabling PayPass antennas: here’s an x-ray of a Visa card issued by BZWBK in Poland. Next step: disabling it. I’ll try to think of something less invasive than previously.

Toying with Atmega8

Kinda works, but something’s still wrong with output voltages, hmmm…


Edit: Of course, a typo late in the night that became obvious in the light of the day. Output-enabled the wrong port. Doh!

R.I.P. PayPass (mBank)

We recently got issued a PayPass-enabled debit card. Not that we wanted one, no. But there seems to be a crazy push for wireless payment going on in Poland and it’s getting hard to get a card without it (or PayWave). Given the security concerns of these solutions (remote cloning), I decided to give it a go and try to disable PayPass while keeping other functions working. Turns out there’s a cheap and fairly reliable way to do it and it involves… x-rays. And drilling. :-)

Here’s what the card I got looks like internally:

You can clearly see where the chip is, how the antenna is connected to it and where it goes on the card. Since it’s basically an RFID chip, it requires an external power source to function. In this case electrical current is inducted in the antenna. In theory it should be enough to break the loop to disable wireless payments. Why not drill through it, then? :D

The card was tested to work OK in ATMs, POS terminals and wirelessly before any changes were made to ensure that it’s the changes that disabled it, not chance. I decided to drill two 3mm holes through it, just to make sure, and here’s what it looked like after the operation:



As you can see I’ve messed up a little bit and drilled right through the magnetic stripe, but it still works! ATMs, POS terminals do, PayPass… doesn’t. Mission successful!



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