A simple yet intriguing idea is worth sharing, even if it wasn’t a flawless success: it can inspire others. [Richard]’s experiment with a motion-powered AirTag fits this bill. Starting with our call for simple projects, [Richard] came up with a circuit that selectively powers an AirTag based on movement. His concept was to use an inertial measurement unit (IMU) and a microcontroller to switch the AirTag on only when it’s on the move, creating a stealthy and battery-efficient tracker.
The setup is minimal: an ESP32 microcontroller, an MPU-6050 IMU, a transistor, and some breadboard magic. [Richard] demonstrates the concept using a clone AirTag due to concerns about soldering leads onto a genuine one. The breadboard-powered clone chirps to life when movement is detected, but that’s where challenges arise. For one, Apple AirTags are notoriously picky about batteries—a lesson learned when Duracell’s bitter coating blocks functionality. And while the prototype works initially, an unfortunate soldering mishap sadly sends the experiment off the rails.
Despite the setbacks, this project may spark a discussion on the possibilities of DIY digital camouflage for Bluetooth trackers. By powering up only when needed, such a device avoids constant broadcasting, making it harder to detect or block. Whether for tracking stolen vehicles or low-profile uses, it’s a concept rich with potential. We talked about this back in 2022, and there’s an interesting 38C3 talk that sheds quite some light on the broadcasting protocols and standards.
Header AirTag: Apple, Public domain, via Wikimedia Commons
Yep, GE patented this concept (with GPS, not air tags) in 1996, US Pat # 5491486: Mobile tracking units employing motion sensors for reducing power consumption therein. Inventors: Welles, II; Kenneth B., Tiemann; Jerome J., Tomlinson, Jr.; Harold W.
The incentive here won’t be reducing power consumption, the esp32 with IMU will consume more than the BLE airtag.
Not meant to discourage, this patent expired ~a decade ago
There’s an openhaystack clone that did this a couple of years ago. Load it onto your favorite esp32 and away you go.
Intermittent activation of the tag once it has ceased movement for X period of time might be more stealthy as it would look more like an intersection with an independently roaming tag than an unknown tag following your device to a tag detection app.
And more useful for knowing where to find your stolen bike.
Also relevant to mention the 38c3 talk on the dangers (of even stealthier) tracking https://media.ccc.de/v/38c3-escaping-big-brother-or-your-ex-counter-surveillance-for-women-s-shelters
Damn man, that talk was heavy. I appreciate their work in explaining what abusers do.
Thanks for posting that.
And less useful for a misplaced item.
My culture has turned so evil. This shouldn’t even be posted. Criminals are using our tech now everywhere. From de-auth wireless security systems to this. This must stop. It promotes stalking and evil. Been a dev for 20 years. This is just disgusting. Please don’t use your emotional logic to justify this kind of research.
Honestly, with the creativity scammers show the past 10 years (like those crazy ATM hacks), I don’t think pointing such simple flaws in tracking devices will stop bad actors from exploiting them.
But at least it gets the conversation going about these issues. Maybe it’ll lead to better regulations or even push companies to open their platforms for better privacy safeguards. It’s not about justifying anything shady—it’s about making the tech safer for everyone.
Because well, censoring talk never stopped tech….
I absolutely disagree. Someone somewhere is experimenting with this stuff, make it public, let everyone know and then something can be done about it. And if somebody wants to use it for nefarious purposes, they will anyway. A hammer is very basic tool but you can’t prevent someone from using it as a weapon. The same logic can be applied here. At least if people are aware of it something can be done.
Having said that, bike crime here is massive. Air tags worked for a bit but police didn’t recognise their ability to track up until recently. Now they are, the thiefs are finding them and removing them before they’re caught.
This particular innovation tackles a specific problem and I’ll be honest if there was a neat enough solution like this for Android I would have one in my bicycle, my car right now (and most likely my laptop and keys too because I can’t currently find them).
While your comment appears valid, remember some countries ban knives and guns with sad results.
There exists a group of people in society who scoff at the law. Your proposed ban would mean that only criminals would have access to this rechnology, just as in those banning countries it’s the criminals who have guns and knives.
With sad results? Like 1/7th to 1/10th the Murder rate of the US? The thing is you can’t use knives or guns after you’ve been shot dead to defend yourself.
You live in a fantasy delusional world. In countries where guns and knives are banned in public, criminals are almost always arrested for having them before they kill someone. Not after they’ve just killed 50 people in three minutes. The country with the most guns to use for self defense has thousands of times more gun deaths per capita.
There’s a group of people who like to pretend that isn’t the case through shared delusions with sad results.
The fastest way to get shot is to hold a gun.
If ingenuity and development would be hinder by type of thinking and fear, we would still in the Stone Age, atomic power is evil, someone will use it for kill millions, industrial machinery is evil because it will leave millions of workers out job and they and their families will starve to death and so many other examples.
Well, atomic power may well end civilization. You can scoff at that, but after the apocalypse you’ll sound very naive and foolish, if anyone’s around to contemplate your blindness.
Yes, no one’s detonated a warhead in war for 80 years. But past performance does not guarantee future results.
Yes bad people do bad things. Will you pay for my stolen car? I’ll be sure to tell the insurance to send the bill to “Voosey”
Most disgusting when someone wants limit freedom of thinking/inventing/tinkering/hacking because bad people do bad things.
Hey I agree and share similar concerns. There are a lot of commercial off the shelf components, and items, cheap ones, that could be used to cause great harm to many individuals. Much of them are not costly at all, and are commodities.
I think we hackers need to take an oath to not create or share destructive technologies. That said, I do not blame hackaday for sharing this, or the author for doing it. Good to decent or even neutral people see this article as completely benign. I believe most people fall under that category.
All we can do is encourage others to be aware of the possible repercussions of their tinkering and their sharing. It is all too easy to destroy and so beautiful to create. I hope you are well and know there are other conscious creators out there.
Think like a white-hat. What can we do to counter these efforts? Make them useless, or so known anyone can be safe? I have ideas. Maybe that is good creative fuel.
I may try this, I have about 6 spare clone tags sitting here from my friends at Vine. They’re pretty cheap, maybe cheap enough to include in a high dollar ebay sale?
I believe that this should be removed, this has potential to insite illegal activity.
Hackaday wouldnt let you post instructions on building a bomb, I don’t think they should put in instructions on how to make untraceable tracking devices.
Why would I want to know where it just when it is moving?
I’d really want to know where it is when it stops moving, so I know where it is.
The tag knows where it is, because it knows where it isn’t…
The author of this article claims it is a battery-efficient tracker which is absolute BS. This device consumes 50-100 times more energy than the airtag alone. Also the original intention is to disable the tracker without movement, so potential car thieves are not able to scan for apple airtags.
Wouldn’t you know based on the last ping?
If the person driving is using an Android or doesn’t have a phone it will never ping. It relies on someone driving or walking past it with an iPhone. So you might know general direction, but it will stop most likely before anyone actually pings it in the final location. Depending on how remote that area is that could be a very long way away indeed.
Most people defending their property would be better off putting it somewhere hard to remove or find, or using it in conjunction with a GPS based tracker that will give a reasonably constant stream of updates while driving.
People using them nefariously would probably be better off just throwing a normal AirTag on the car. Though Apple will tell the police that their ex partner or whatever owns that tag among other things.
I suppose if you knew the target had an iPhone, but it would still alert them while driving, they may not be able to find it if it’s off while stopped, but if you’re at risk that’s still a flag to drive somewhere safe to more extensively search hopefully.
Imagine that with TimeCapsule airtag
https://www.elevationlab.com/products/timecapsule?srsltid=AfmBOopJ57NAEAl-0r9kTZjqDUo4b6WpedWxALIN9yCXfN6HBXAqBm0h
A device that’s good for tracking stolen goods is also necessarily good for tracking people without their knowledge in a stalky sense too.
I really like Maya Posch’s article on this dilemma: https://hackaday.com/2023/05/22/airtags-tiles-smarttags-and-the-dilemmas-of-personal-tracking-devices
I wonder if Apple knew the scope of the Pandora’s Box they opened up when they decided to roll out a worldwide anonymous tracking network? Or if they were just YOLO, it finds my keys?
One one hand $$$$$ on other hand meh ethics. It’s obvious which one they chose.
My cheaper Atuvos tags now only work on my phone for some reason (they allow me to know if I left them behind, that’s it, but they used to work before). Are original 🍏tags still working as expected?
Not sure what Apple knew originally but they certainly have a number of ways of making it very much not anonymous when law enforcement gets involved. That and the tracker moving with you alerts etc.
As trackers go it seems to be one of the worst possible for tracking people without their knowledge but for the price and accessibility of it.
It’s great for tracking your suitcases, and I used it to track my stuff when I moved. Though interestingly at one point the AirTags I used, after giving me an updated location at the port, a day later decided to, from every device I tried, give me the location of where they were a day earlier. I do wonder if that was an anti stalking measure, given the truck drivers probably drove with it for a day or so (though they would only occasionally ping from inside a shipping container, and not all of them).
And the ultra wide band is great for finding your keys.
if you want to use an AirTag in a automobile and only have it transmit when the car is moving, why not power it from the brake light? Have a capacitor that gets charged up enough to power the AirTag long enough to report its location and then run out of charge . Of course it won’t do much for thieves with tow trucks, until they try to power up the car.
of course, one AirTag deployed normally that the thieves would find and a stealth AirTag that they wouldn’t bother looking for because they’d already found the AirTag would be ideal.
There’s far easier, more battery efficient ways to do this, if you don’t need the precision of an accelerometer. For example using a spring and a MOSFET instead of the MCU+IMU+transistor:
Set up the spring so that it touches a piece of metal when it oscillates. Wire the spring to 3v3, the contact to a logic level MOSFET gate, add gate-source capacitor and bleeding resistor as needed. It won’t give you perfect on-off voltage, but it should be good enough for an airtag. I’ve used this same circuit but with a BJT and ~100uF capacitor, using the base current as bleed, to get some nice LED fade light upon movement
I’ve done similar to this with these
https://signalquest.com/products/?16=y
both with an analog backend and also
running the pulses into the counter of an MSP430
in low power mode. Wake up the MSP, do some quick
IIR filtering, either turn on or go back to sleep.
if you want to use an AirTag in a automobile and only have it transmit when the car is moving, why not power it from the brake light? Have a capacitor that gets charged up enough to power the AirTag long enough to report its location and then run out of charge . Of course it won’t do much for thieves with tow trucks, until they try to power up the car.
of course, one AirTag deployed normally that the thieves would find and a stealth AirTag that they wouldn’t bother looking for because they’d already found the AirTag would be ideal.
or just add movement detector to the airtag
Bah, could have used a 555 timer!
No, really. One-shot config triggered by a vibration switch
555 is not reliable for long time periods, nor temperature stable, the solution is always an extra MCU.
Correct(ish)
But here you don’t need accurate timing … at all.
Besides using more power than the Air tag alone, it effectively defeats the purpose of an air tag since the location requires regular transmission to random iPhones that happen into the proximity of the tag. If it is not continuously powered the tags location will likely not be captured by other devices.
There’s a bike tracker that does exactly this! It works with Apple’s Find My network, but only powers on when the bike is being pedaled. Wish I could remember the make or model to provide a link, but it’s a commercially available product.