As shown in the diagram below the device has a hidden camera embedded on one side to read cards remotely. The infrared (IR) filter was removed to allow it to interpret IR light.
There are three concealed IR LEDs next to it which illuminate the deck to make the markings on the cards visible to the camera.
A cool trick is that the phone housing is made of IR passband plastic: although the phone side appears to be sturdy and opaque, it actually allows IR light to traverse.
The best way to illustrate this behavior is to take a picture of the device while it is powered on in the dark with a camera with no IR filter, as seen in the photo above. As you can see, doing so, the three LEDs are clearly visible. The best thing about it is that phone cameras are very sensitive to IR light, so pointing your phone camera to a poker cheating system would reveal the gigantic blow of light.
What makes the whole thing work is using a special box, in which each card's four edges are labelled with IR-absorbing ink. Consequently, when the IR LEDs illuminate this marked plate, the ink spots absorb the IR, forming a sequence of black spots as seen in the above illustration. This can be contrasted with a standard deck which, when illuminated with IR, shows no markings as is also visible in the picture.
The sequence of black spots produced by the IR illumination, illustrated in the above illustration, is remotely read by the cheating system to infer the suit and value of a card. Those labels can be thought of as transparent barcodes.
Each card has a unique code, as shown in the image above, showing the markings for the six hearts, six clubs, six diamonds, five diamonds, and five hearts. On each side of a coin, those markings are replicated. Originally, we thought there was some sort of order, but it turns out that for each card the marking encodes only a known value. We assume the values were chosen to optimize reader accuracy, possibly something like a Gray code.
An fascinating problem is how the labels are put on the cards. I would have tried to build a deck from the ground up at first, but after closely examining a few decks, it's obvious they're using a real Bicycle Deck (or any brand you want) and using a dedicated machine to label them.
This marking process leaves a rather subtle but noticeable indication, as noted by an anonymous source: the corners of the cards are slightly cut. We assume the labeling process is to help.
When you order a pack of marked cards, it is delivered with its "intact" seal and plastic wrap, as seen in the above picture. It makes the scam victims less suspicious, because the pack can be opened before their eyes.
The way the seal is retained, however, is less than ideal: instead of messing with the seal and removing it (an simple feat!), they chose to cut the bottom of the box as seen in the above picture. This can be quickly noticed by looking at the box of cards, although it would have been impossible to tamper with the lock.
To really understand how good this cheating tool is, it is worth highlighting some of the main challenges faced while using high-end card cheating technology. In addition to the need to create custom hardware and a card marking process, reading cards correctly in real time is difficult for three additional reasons:
- The algorithm must realign the reading to account for the location of a card (angle and rotation) and deal with cards that may be misaligned or bent.
- Reading and decoding must be fast which is not trivial on an underpowered computer. It is not surprising, given this need for speed, that the entire recognition algorithm has been implemented in C and not in Java.
- Cards are very small, meaning their markings are only a few pixels wide. Reading those with a camera with low resolution 30 cm away leaves no space for error.
Here is the poker reader's exposed view prototype in practice, showing what the system sees when I placed the deck on the table and showing how easy it is to detect the cards:
Now that we know how the device operates, let's see how it gets applied by breaking down the device in hardware. Removing the enclosure shows that the hidden camera is attached to a dedicated chip, as seen in the picture above. The removal of the black tape at the top left corner shows the IR LEDs, as seen in the screenshot below.
Notice the right hand side of the phone's RF and Bluetooth antenna connectors. These are also controlled by the specific chip, and are used to communicate with the accessories. RF links the video camera and remote control, while Bluetooth links with the audio and haptic output tools.