Laser Mic Makes Eavesdropping Remarkably Simple

September 25, 2010 by Mike Szczys 56 Comments

Here’s a surprisly simple way to build yourself a laser-based listening device. It consists of two modules, a transmitter and a receiver. The transmitter is a set of lasers, one is visible red for aiming, and the other is infrared for measuring the vibration of a surface. Point the transmitter at the window of the room you want to listen in on and the laser can be reflected back to the receiver. The receiver module has a phototransistor to pick up the infrared laser light, and an LM386 audio amplifier to generate the audio signal sent to a pair of headphone. The need to be well-aligned which is easy enough using a pair of tripods. Check out the demo after the break.

Looking for something to do with the leftover laser diodes from this project? Try making yourself a laser microscope.

Continue reading “Laser Mic Makes Eavesdropping Remarkably Simple” →

RFID Readers, Writers, And Spoofers

September 25, 2010 by Mike Szczys 12 Comments

[Carl] has done a lot of work developing a collection of RFID hardware. The two cards you see above are spoofers that can be programmed in the field using the keypad on the left, or the rather intimidating banks of DIP switches on the right. We also enjoyed his look at the Atmel T5557 and ATA5567 on-card chips used for the tags themselves. He shared the schematics for his designs but unfortunately he’s not distributing the firmware. None-the-less, if you’re interested in learning more about RFID this is a wonderful resource as it covers readers, writers, spoofer, and tags.

Unmanned Ocean Crossing

September 24, 2010 by Mike Szczys 24 Comments

This is the Pinta, an autonomous sailboat built to attempt an ocean crossing from Ireland to Martinique (in the Caribbean). A group of researchers at Aberystwyth University built her as part of the Microtransat Challenge.

To keep tabs on the vessel her creators included an Iridium short burst data modem with a backup system made from a SPOT satellite tracker using a PIC microcontroller to trigger a transmission every six hours. The sailing systems are a conglomeration of a Gumstix board, GPS, a windshield wiper motor to control the sail, and a tiller pilot for steering. A set of solar panels helps to top off the lead-acid batteries that power the system.

Unfortunately the old gal has encountered problems. You can see from the tracking data that, although it sailed 500 km in the last twelve days, she is still just off the coast of Ireland. The primary tracking system has failed, which could signal a system-wide computer failure. We hope the team will eventually recover the vessel as we’re interested in finding out what caused this unfortunate turn of events.

Gutting An Air Freshener For The Parts

September 24, 2010 by Mike Szczys 40 Comments

[Doug Paradis] took a good look inside the Air Wick Freshmatic Compact i-Motion and then stole all the parts for other projects. We’ve looked at adding a manual spray button or making air fresheners Internet enabled before. Those models didn’t have parts that were all that interesting, but this one has a passive infrared motion sensor. You’ll also gain three switches, a PNP transistor, and an LED.

Price seems to be all over the map for this model, but [Doug] says you can find it for $8 or less. After showing how to make a tool to bypass the triangular security screws, he explains how to access the PIR sensor. But if you want to be all you can be with the hardware, he details the modifications needed to patch into the analog and digital circuitry on the rest of the board too.

The HDCP Master Key

September 24, 2010 by Mike Szczys 23 Comments

Pastebin has the HDCP master key that we talked about in a post last week. This is the encryption protocol used for HDMI content protection on media such as Blu-Ray and High Definition cable television.

The master key array is a 40×40 set of 56-bit hex used to generate the key sets. You get one brief paragraph at the top of the document explaining what to do with this information. If you ask us we’re more interested in how this set was determined. So for some background information read the key selection vector (KSV) Wikipedia page. That points us to an interesting discussion proposing that if 40 unique device-specific KSVs can be captured, they could be used to reverse-engineer the master key. And finally, a bit of insight from a Reddit user (make your own decision on the dependability of this information) commenting on the value of having the master key.

In his comment, [iHelix150] covers the revocation system that HDCP uses to ban devices that are being used to circumvent copy protection. He says that having the master key makes it possible to push your own revocation lists onto devices. Each time a list is written to your device (TV, Blu-ray, etc.) the version number field for the list is updated. If you push an update with nothing on the revocation list, and set the version number to a binary value of all 1’s it will prevent any more rewrites of the list. This means that any previously banned hardware will be allowed back into the chain or trust.

So far this probably means nothing for you. But it’s fun to watch the cat-and-mouse involved in the DRM struggle, isn’t it?

Full-featured AVR Time-lapse

September 24, 2010 by Mike Szczys 11 Comments

This time-lapse photo trigger was built [Lukasz Goralczyk]. It is controlled by an ATmega168 and we were surprised to read that it uses about 12k of code. Curious about what takes up that much space, we were impressed to see all the features demonstrated in the video after the break. The small device, running on two AA batteries, has a well-designed user interface displayed on a 3V character LCD that is navigated with a clickable rotary encoder.

It isn’t the smallest intervalometer we’ve ever seen, but it deserves respect for the features packed into a diminutive form-factor.

Continue reading “Full-featured AVR Time-lapse” →

WiFi AP Gets Antenna Augmentation

September 23, 2010 by Mike Szczys 29 Comments

Feeling bad that his access point was being made fun of by models with beefier external antennas, [Customer Service] decided to do something about it. After cracking open the Asus wl-330ge he found it would be quite easy to add a connector. This access point has two internal antennas that are quite small and use a spring connection to the signal and ground pads on the PCB. Those pads are fairly large and separated, making it easy to solder the connections. Scavenging an antenna connector from an older device, [Customer Service] soldered it in place and drilled a mounting hole in the plastic case. After flashing DD-WRT firmware he’s now got everything he wants from the little guy.