WISP: Battery-free computer that can be reprogrammed wirelessly

Re:WISP: Battery-free computer that can be reprogrammed wire... by beambot on Monday April 25, 2016 @06:52AM (#11563453)

The two most-common commercial options are Impinj and ThingMagic readers. Neither are open-source (hardware or firmware) -- they just have APIs. If you go back to the old ThingMagic M5e (rather than newer M6e), there are high-level open source libraries that I wrote:

Documentation: http://wiki.ros.org/hrl_rfid

On GitHub: https://github.com/gt-ros-pkg/hrl/blob/master/hrl_rfid/src/h...

You can buy single-chip readers from AMS (eg. on DigiKey) and build your own reader -- not a light undertaking due to RF PCB layouts, but manageable. I've also heard of people using the USRP (GNU Radio) to build gen2-compliant UHF RFID readers, but I believe they require the PCI-bus variant to adhere to protocol timing standards.

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Re:WISP: Battery-free computer that can be reprogrammed wire... by elcritch on Monday April 25, 2016 @11:43PM (#11569282)

Fantastic! I appreciate the heads-up. The open source ThingMagic drivers would be very handy.

It has crossed my mind to try integrating a single-chip reader but I'm unsure of what the FCC requirements would be for selling it as part of a commercial product. It's a little surprising that there hasn't been a kickstarter type of project to build an open source reader chip and get it FCC spec'ed.

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Re:WISP: Battery-free computer that can be reprogrammed wire... by beambot on Tuesday April 26, 2016 @12:42AM (#11569495)

The AMS chip itself is probably FCC compliant, since the output power is so low (10-13dBM, IIRC). The problem arises when you add an external PA to get the full 30dBm output power permitted by the FCC; then you need to re-certify.

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