WiFi Streaming Radio Update

February 3, 2009 by Nick Caiello 6 Comments

[flickr video=3238566442]

Since our last post about his WiFi Streaming Radio Project, [Jeff] has been hard at work to release part 8 of the project where he adds tuning control to the radio. Interestingly enough, the addition of the tuning control only requires a potentiometer and the completed AVR LCD board from part 7. After wiring the potentiometer to the analog to digital converter on the AVR and adding a few lines of code, the radio can now be tuned quickly and easily. In addition to thoroughly explaining the hardware changes, [Jeff] details the configuration changes required to the OpenWRT framework so that bidirectional communication between the router and AVR is possible, allowing the tuner to function properly. Be sure to check out the video above to see the tuner in action.

Mobile RFID Scanning

February 2, 2009 by Eliot 18 Comments

[youtube=http://www.youtube.com/watch?v=9isKnDiJNPk]

[Chris Paget] is going to be presenting at ShmooCon 2009 in Washington D.C. this week. He gave a preview of his RFID talk to The Register. The video above demos reading and logging unique IDs of random tags and Passport Cards while cruising around San Francisco. He’s using a Symbol XR400 RFID reader and a Motorola AN400 patch antenna mounted inside of his car. This is industrial gear usually used to track the movement of packages or livestock. It’s a generation newer than what Flexilis used to set their distance reading records in 2005.

The unique ID number on Passport Cards doesn’t divulge the owners private details, but it’s still unique to them. It can be used to track the owner and when combined with other details, like their RFID credit card, a profile of that person can be built. This is why the ACLU opposes Passport Cards in their current form. The US does provide a shielding sleeve for the card… of course it’s mailed to you with the card placed outside of the sleeve.

Technology exists to generate a random ID every time an RFID card is being read. The RFIDIOt tools were recently updated for RANDOM_UID support.

[Thanks Zort]

Eye-Fi Teardown

February 1, 2009 by Eliot 44 Comments

eye-fi

[les robots] had a defective Eye-Fi card on his hands and when a replacement was sent, he was told to destroy the original. What better way to ‘destroy’ something than opening the case? The Eye-Fi is an SD card with a builtin WiFi radio so it can upload images while remaining in camera. One version uses Skyhook’s location service to geotag photos. You can see a few photos of the dismantled card on Flickr. The board is manufactured by Wintec. The wireless side is handled by Atheros’ ROCm, the same low power Radio-on-Chip module you would find in a mobile phone. The flash memory comes from Samsung and the antenna is along the back edge, where it has the best chance of getting signal.

UHF Power Harvesting

January 29, 2009 by Eliot 15 Comments

hdpowerharvesting

[Alanson Sample] and [Joshua R. Smith] have been experimenting with wireless power transfer for their sensing platform. Their microcontroller of choice is the MSP430, which we used on our e-paper clock. They chose it specifically for its ability to work with low voltages and they discus its specific behavior at different voltages. The first portion of their paper uses a UHF RFID reader to transmit to the sensor’s four stage charge pump. They added a supercap to provide enough power for 24 hours of logging while the node isn’t near a reader. For the second half of the paper, they use a UHF antenna designed for digital TV with the same circuit and pointed it at a television tower ~4.1km away. It had an open circuit voltage of 5.0V and 0.7V across an 8KOhm load, which works out to be 60uW of power. They connected this to the AAA battery terminals of the thermometer/hygrometer pictured above. It worked without issue. The thermometer’s draw on a lab power supply was 25uA at 1.5V.

It’s an interesting approach to powering devices. Do you have an application that needs something like this? For more on wireless power, checkout this earlier post on scratch building RFID tags.

[via DVICE]

TEMPEST: A Signal Problem

January 25, 2009 by Eliot 12 Comments

TEMPEST is the covername used by the NSA and other agencies to talk about emissions from computing machinery that can divulge what the equipment is processing. We’ve covered a few projects in the past that specifically intercept EM radiation. TEMPEST for Eliza can transmit via AM using a CRT monitor, and just last Fall a group showed how to monitor USB keyboards remotely. Through the Freedom of Information Act, an interesting article from 1972 has been released. TEMPEST: A Signal Problem (PDF link dead, try Internet Archive version) covers the early history of how this phenomenon was discovered. Uncovered by Bell Labs in WWII, it affected a piece of encryption gear they were supplying to the military. The plaintext could be read over that air and also by monitoring spikes on the powerlines. Their new, heavily shielded and line filtered version of the device was rejected by the military who simply told commanders to monitor a 100 feet around their post to prevent eavesdropping. It’s an interesting read and also covers acoustic monitoring. This is just the US history of TEMPEST though, but from the anecdotes it sounds like their enemies were not just keeping pace but were also better informed.

[via Schneier]

WiFi Theremin

January 23, 2009 by Eliot 9 Comments

The fine folks at Midnight Research Labs have put together a new toy for you to play with. It’s a Python script that makes your WiFi hardware behave more like a theremin. Based on the pyaudio library it monitors the signal strength of the AP you’re connected to and changes the tone accordingly. There’s a sample embedded above (direct link). If you have a second interface, you can use it to modulate the volume. It’s an interesting trick, but they say that there’s enough latency that it would be hard to play actual music with it.

External Antenna On Panasonic CF-R1

January 21, 2009 by Caleb Kraft 15 Comments

ext_ant

[Steven] managed to get his hands on a Panasonic CF-R1 for pretty cheap. Though it is a decently powerful machine, it was built in 2002 and didn’t come with an internal wireless card. It did, however have a mini-PCI slot. [Steven] promptly installed a wireless card, but found the internal antenna lacking. The solution was to custom mount an external antenna. Mounting it was fairly easy, he removed the phone jack and epoxied the connector in its place. The reception was greatly improved. He says he went from seeing 6 access points to 31 as soon as he installed it. Similar things have been done to the Eee PC 900.