Mobile phone reading an NFC tag with information on a garden plant

NFC Puts A Stake In The Ground

Sometimes we have a new part or piece of tech that we want to use, and it feels like a solution looking for a problem. Upon first encountering NFC Tags, [nalanj] was looking for an application and thought they might make a great update to old-fashioned plant markers in a garden. Those are usually small and, being outside 24/7, the elements tend to wear away at what little information they hold.

traditional plant marker

[nalanj] used a freeform data structuring service called Cardinal to set up text information fields for each plant and even photos. Once a template has been created, every entry gets a unique URL that’s perfect for writing to an NFC tag. See the blog post on Cardinal’s site for the whole process, the thought behind the physical design of the NFC tag holder, and a great application of a pause in the 3D print to encapsulate the tags.

NFC tags are super hackable, though, so you don’t have to limit yourself to lookups in a plant database. Heck, you could throw away your door keys.

Adding Smart Watch Features To Vintage Casio

[Matteo] has been a fan of the Casio F-91W wristwatch virtually since its release in 1989. And not without good reason, either. The watch boasts reliable timekeeping and extremely long battery life thanks to a modern quartz crystal and has just about every feature needed in a watch such as an alarm and a timer. And, since it’s been in use since the 80s, it’s also a device built to last. The only thing that’s really missing from it, at least as far as [Matteo] was concerned, was a contactless payment ability.

Contactless systems use near-field communication (NFC) to remotely power a small chip via a radio antenna when in close proximity. All that’s really required for a system like this is to figure out a way to get a chip and an antenna and to place them inside a new device. [Matteo] scavenges the chip from a payment card, but then builds a new antenna by hand in order to ensure that it fits into the smaller watch face. Using a NanoVNA as an antenna analyzer he is able to recreate the performance of the original antenna setup in the smaller form factor and verify everything works before sealing it all up in a 3D-printed enclosure that sandwiches the watch.

There are a few reasons why using a contactless payment system with a watch like this, instead of relying on a smartwatch, might be preferential. For one, [Matteo] hopes to explore the idea that one of the physical buttons on the watch could be used to physically disable the device to reduce pickpocketing risk if needed. It’s also good to not have to buy the latest high-dollar tech gadget just for conveniences like this too, but we’ve seen in the past that it’s not too hard just to get these systems out of their cards in the first place.

Hacking A “Smart” Electric Toothbrush To Reset Its Usage Counter

The visible circuitry inside the brush head.
The visible circuitry inside the brush head.

Following the trend of stuffing more electronics in everyday devices, the new Philips Sonicare electric toothbrush that [Cyrill K├╝nzi] purchased ended up having a ‘brush head replacement reminder’ feature that wasn’t simply a timer in the handle or base of the unit, but ended up involving an NFC chip embedded in every single brush head containing the usage timer for that particular head. Naturally, this asked for it to be solidly reverse-engineered and hacked.

The NFC chip inside the brush head turned out to be an NXP NTAG213, with the head happily communicating with the NFC reader in a smartphone and the NFC Tools app. This also revealed the memory layout and a few sections that had write access protected by a password, one of which was likely to be the counter. This turned out to be address 0x24, with a few experiments showing the 32-bit value at this address counting the seconds the brush head had been used.

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NFC Antennas Have Other Uses

As NFC chips proliferate, so do the antennas they require for operation, and since many NFC-enabled items are single-use, this means there’s an opportunity to put them to other uses. It’s an avenue pursued by [Brother-live], as he strips the antennas from spent metro tickets and gets experimenting.

The antenna in an NFC-enabled card is a flexible PCB laminated between the plastic outer layers, with the tracks forming a coil round the outside of it. Using some solvent the cards can be easily separated and the antennas retrieved. Once the chip has been removed they can be cleaned up and soldered to, allowing wires to be connected.

What can you do with an NFC antenna? Not a huge amount as you can see in the (Russian language, English subtitles) video below the break, but he tries it as a not-very-good heating pad, a power harvesting antenna from NFC readers, and perhaps most promisingly, as the coil of a moving-coil speaker. We’re not sure how much effort would be worth making on that last front, but we think with a bit of care there might be room for audible improvement.

If you’ve ever been tempted to have a look at an NFC card, it’s a subject we’ve covered before.

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A grey smartphone sits inside a sleeve made of light brown wood veneer and a black felt interior.

Wooden Smartphone Sleeve Keeps You On Task

Smartphones are amazing tools, but sometimes they can be an equally amazing time suck. In an effort to minimize how much precious time goes down the drain, [Lance Pan and Zeynep Kirmiziyesil] decided to make a functional and beautiful smartphone sleeve to keep you on task.

Most modern smartphones have some form of Do Not Disturb mode available, but having the phone visible can still be an invitation for distraction. By tucking the phone into an accessible but less visible sleeve, one can reduce the visual trigger to be on the phone while keeping it handy in the even of an emergency.

Once in the sleeve, the NFC tag sandwiched between the felt and wood veneer triggers an automation to put the phone into Do Not Disturb mode. This hack looks like something that you could easily pull off in an afternoon and looks great which is always a winning combination in our book.

To see some more focus-oriented hacks, checkout the Pomodachi or this Offline E-Paper Typewriter.

Kids’ Jukebox Based On Arduino With RFID

Consumer electronics aimed at young children tend to be quite janky and cheap-looking, and they often have to be to survive the extreme stress-testing normal use in this situation. You could buy a higher quality item intended for normal use, but this carries the risk of burning a hole in the pockets of the parents. To thread the needle on this dilemma for a child’s audiobook player, [Turi] built the Grimmboy for a relative of his.

Taking its name from the Brothers Grimm, the player is able of playing a number of children’s stories and fables in multiple languages, with each physically represented by a small cassette tape likeness with an RFID tag hidden in each one. A tape can be selected and placed in the player, and the Arduino at the center of it will recognize the tag and play the corresponding MP3 file stored locally on an SD card. There are simple controls and all the circuitry to support its lithium battery as well. All of the source code that [Turi] used to build this is available on the project’s GitHub page.

This was also featured at the Arudino blog as well, and we actually featured a similar project a while ago with a slightly different spin. Both are based on ideas from Tonuino, an open source project aimed at turning Arduinos into MP3 players. If you’re looking to build something with a few more features, though, take a look at this custom build based on the RP2040 microcontroller instead.

HunterCatNFC tool

Hunt Down NFC Signals With This NFC Multi Tool

NFC hacking can be a daunting task with many specialized tools, a proliferation of protocols, and a multitude of different devices. [ElectronicCats] has done a lot of work to try to make this investigation accessible by creating an open-source, hardware-certified NFC tool called the HunterCatNFC that can read and emulate a multitude of NFC devices.

The HunterCatNFC device is meant to be portable and self contained, with LED indicator lights that can give information about the various modes, and feedback about what data is being received. At its core, the HunterCatNFC has an NXP PN7150 NFC controller chip to handle the NFC communication. The main processing controller is a Microchip SAMD21 which also provides USB functionality, and the whole device is powered by a 3.7V 150mAh Li-ion battery.

The HunterCatNFC has three main modes, ’emulation’, ‘read/write’ and ‘peer-to-peer’. Emulation mode allows the HunterCatNFC to mimic the functionality of a passive NFC device, only responding when an NFC reader issues a request. The read/write mode allows it to emulate an NFC reader or writer, with the ability to communicate with nearby passive NFC devices. The peer-to-peer mode gives the device the ability to have two way communication, for instance, between two HunterCatNFC devices.

We’ve covered NFC hacking before, including the Flipper Zero. The HunterCatNFC is a fine addition to the NFC hackers arsenal of tools with some very nice documentation to learn from. For those not wanting to send out their own boards to be printed and assembled, [ElectronicCats] has them for sale.

Video after the break!

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