The folks at SparkFun were startled by how small USB bluetooth adapters had become so they split one open. They noted a few interesting design features. It has a small folded trace antenna on the board edge. The metal USB housing acts as the RF shield. The bluetooth IC is an AS3620QA. Now we wonder what those tiny Buffalo drives look like inside.
Related: Eye-Fi teardown, storage/WiFi in an SD card
[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]
[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]
[Shadow] sent in this handy idea. For many, it’s sort of a captain obvious hack, but I’m hoping that this might keep a few of these things out of the trash. He needed to send video around the house from a media PC, and happened to have an old XBox RF modulator sitting around. He popped it apart and located the audio and composite video inputs. To get the signal to the rest of the house, he plans on installing a distribution amplifier that’ll amplify and split the signal to each TV set.
