Long-Range RFID Leaflets

Pick a card, any card. [Andrew Quitmeyer] and [Madeline Schwartzman] make sure that any card you pick will match their NYC art installation. “Replantment” is an interactive art installation which invites guests to view full-size leaf molds casts from around the world.

A receipt file with leaf images is kept out of range in this art installation. When a viewer selects one, and carries it to the viewing area, an RFID reader tells an Arduino which tag has been detected. Solid-state relays control two recycled clothing conveyors draped with clear curtains. The simple units used to be back-and-forth control but through dead-reckoning, they can present any leaf mold cast front-and-center.

Clothing conveyors from the last century weren’t this smart before, and it begs the question about inventory automation in small businesses or businesses with limited space.

We haven’t seen much long-range RFID, probably because of cost. Ordinary tags have been read at a distance with this portable reader though, and NFC has been transmitted across a room, sort of.

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ATtiny Chip Abused in RFID Application

One of Atmel’s smallest microcontrollers, the ATtiny, is among the most inexpensive and reliable chips around for small applications. It’s also one of the most popular. If you don’t need more than a few inputs or outputs, there’s nothing better. As a show of its ability to thrive under adverse conditions, [Trammell Hudson] was able to shoehorn an ATtiny into an RFID circuit in a way that tests the limits of the chip design.

The RFID circuit only uses two of the ATtiny’s pins and neither of which is the ground or power pin. The ATtiny is equipped with protective diodes on its input pins, and if you apply an AC waveform to the input pins, the chip is able to use the leakage current to power itself. Once that little hurdle is crossed, the ATtiny can do the rest of its job handling the RFID circuitry.

This project takes a deep dive into the internals of the ATtiny. If you’ve ever wondered what was going on inside of everyone’s favorite tiny microcontroller, or if you’re looking for an RFID circuit that keeps parts counts to an absolute minimum, this is the project for you.  The ATtiny is more than just a rugged, well-designed chip, though. It’s capable of a lot more than such a small chip should be able to.

Thanks to [adnidor] for the tip!

Samy Kamkar: Reverse Engineering for a Secure Future

Show of hands: how many of you have parked your car in the driveway, walked up to your house, and pressed your car’s key fob button thinking it would open the front door? We’ve probably all done it and felt a little dopey as a result, but when you think about it, it would be tremendously convenient, especially with grocery bags dangling off each arm and the mail clenched between your teeth. After all, we’re living in the future —  shouldn’t your house be smart enough to know when you’re home?

Reverse engineer par excellence Samy Kamkar might think so, but given his recent experiences with cars smart enough to know when you’re standing outside them, he’d probably have some reservations. Samy dropped by the 2017 Hackaday Superconference in November to discuss the finer points of exploiting security flaws in passive car entry systems, and also sat down with our own Elliot Williams after his talk for a one-on-one interview. Samy has some interesting insights on vehicle cybersecurity, but the practical knowledge he’s gained while exploring the limits of these systems teach some powerful lessons about being a real-world reverse engineer.

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Hackaday Prize Entry: Unlock Your PC The RFID Way

Sometimes we see projects whose name describes very well what is being achieved, without conveying the extra useful dimension they also deliver. So it is with [Prasanth KS]’s Windows PC Lock/Unlock Using RFID. On the face of it this is a project for unlocking a Windows PC, but when you sit down and read through it you discover a rather useful primer for complete RFID newbies on how to put together an RFID project. Even the target doesn’t do it justice, there is no reason why this couldn’t be used with any other of the popular PC operating systems besides Windows.

The project takes an MRFC-522 RFID module and explains how to interface it to an Arduino. In this case the Arduino in question is an Arduino Pro Micro chosen for its ability to be a USB host. The supplied code behaves as a keyboard, sending the keystroke sequence to the computer required to unlock it. The whole is mounted in what seems to be a 3D printed enclosure, and for ease of use the guts of the RFID tag have been mounted in a ring.

As we said above though, the point of this project stretches beyond a mere PC unlocker. Any straightforward RFID task could use this as a basis, and if USB is not a requirement then it could easily use a more run-of-the-mill Arduino. If you’re an RFID newbie, give it a read.

Plenty of RFID projects have made it here before, such as this door lock. And we’ve had another tag in a ring, too.

Hybrid Technique Breaks Backscatter Distance Barrier

Low cost, long range, or low power — when it comes to wireless connectivity, historically you’ve only been able to pick two. But a group at the University of Washington appears to have made a breakthrough in backscatter communications that allows reliable data transfer over 2.8 kilometers using only microwatts, and for pennies apiece.

For those unfamiliar with backscatter, it’s a very cool technology that modulates data onto RF energy incident from some local source, like an FM broadcast station or nearby WiFi router. Since the backscatter device doesn’t need to power local oscillators or other hungry components, it has negligible power requirements. Traditionally, though, that has given backscatter devices a range of a few hundred meters at most. The UW team, led by [Shyamnath Gollokota], describe a new backscatter technique (PDF link) that blows away previous records. By combining the spread-spectrum modulation of LoRa with the switched attenuation of incident RF energy that forms the basis for backscatter, the UW team was able to cover 2800 meters for under 10 microwatts. What’s more, with printable batteries or cheap button cells, the backscatter tags can be made for as little as 10 cents a piece. The possibilities for cheap agricultural sensors, ultracompact and low power wearable sensors, or even just deploy-and-forget IoT devices are endless.

We’ve covered backscatter before, both for agricultural uses and for pirate broadcasting stations. Backscatter also has also seen more cloak and dagger duty.

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Hackaday Prize Entry: Refugee Reuniter

The world is dealing with a serious refugee crisis, and with that comes a problem: finding people. The Refugee Reuniter, a project entered into this year’s Hackaday Prize, is a possible solution to this problem. It’s a device that allows people to reconnect with their family, whether it’s children lost in transit to destination countries, or mothers and fathers reuniting.

The basic problem the Refugee Reuniter is trying to solve is tracking people. This is a whole ball of wax that involves privacy and technological concerns. Ideas put forward so far include GPS trackers, implantable RFID tags, and other such draconian measures. The Refugee Reuniter puts another spin on this, while still assigning a unique, electronic ID to every name.

The basic hardware for the Refugee Reuniter is simply an RFID wristband or token, carried with the refugee at all times. This token is mapped to a name that can be looked up in a small terminal, tied to a specific location. If a refugee logs into one of these terminals, their location is logged and they can search for their relatives. It’s a simple technological solution to what is basically a gigantic dead-tree logbook, only backed up into an online database.

Creepy Tracking at the House of Mouse

If it’s been a few years since you’ve been to Disney World, you’re in for a surprise on your next visit. It seems the Happiest Place on Earth has become the Trackiest Place on Earth thanks to the Disney MagicBand, a multipurpose wristband that acts as your pass to all the Disney magic.

[Adam] recently returned from a Disney vacation and brought back his MagicBand, which quickly went under the knife for a peek at the magic inside. It turns out the technology is fairly mundane — a couple of flex PCBs with trace antennas and the usual trappings of an RFID transponder. But there’s also another antenna and a chip identified in a separate teardown as an NRF24LE1 2.4 GHz transceiver and microcontroller. The whole thing is powered by a coin cell, meaning the band isn’t just being interrogated by RFID – it’s actively transmitting and receiving.

What exactly it’s doing isn’t clear; Disney was characteristically cagey about specifics when [Adam] looked into the details, saying only that the bands “provide information that helps us improve the overall experience in our parks”. If you put aside the privacy concerns, it’s truly mind-boggling to think about the systems that must be in place to track thousands of these MagicBands around the enormous Disney property. And we can’t help but wonder if some of Disney R&D’s EM-Sense technology is at work in these wearables.

Thanks to [JohnU] for the tip.