It must be incredible, but horrifying too. Apple iPhone 5s seemingly keeps tracking users’ every move even after the battery has died. The reason is when a battery dies, the phone still carries a little amount of charge, which means its low-energy chip can keep saving data from built-in motion sensors. However, it factually can’t track locations, but it can tell how many footsteps a user takes, or make out whether a phone was still being carried around.
Recently, while on a four-day trip in Europe, programmer Arman Amin uncovered that the Argus fitness app on his iPhone 5s had kept information of the footsteps taken on his journey even though his phone was shut off. When Amin’s charging cable broke, the battery of his phone died soon after. So he didn’t want to carry the dead phone in his bag. He put his phone on charge again after returning from his vacation.
When he switched his iPhone on after 4 days, the number of footsteps he had made were recorded on a pedometer app, meaning motion sensors were still running. On a news-sharing web Reddit, Amin shared and penned his revelation as user Glarznak.
Glarznak wrote: ‘‘I frequently use Argus to track my steps since it takes advantage of the M-7 chip built into the phone. Once I got back from my vacation, and charged the phone, I was surprised to see that Argus displayed a number of steps for the four days that my phone was dead.’’
On Reddit, Glarznak’s conclusion was pretty interesting: “I’m both incredibly impressed and slightly terrified.”
Apple’s iPhone 5s has the M-7 motion co-processor. The chip tracks users’ steps and feeds the data to third-party fitness apps. And as it turns out that the M-7 may not even require the iPhone 5s to be powered on in order to track the owner’s movements.
Apple phones and other devices, usually keep a power standby, even after the phone switches off, so that it can continue particular facilities and help it boot up if put on charge again. For instance, if a phone display shows zero battery, still there is around 5% charge left.
The M-7 does not collect data from the GPS unit, because this unit takes up a lot of power and is controlled by a separate chip. This means that though Glarznak’s phone could track his footsteps, it wasn’t able to track his location.
All the data the M-7 collects is encrypted and removed after 7 days. It also couldn’t be accessed by Apple’s built-in apps–only by apps developed by third parties. Users also need to let an app to use motion data, by opting in–it is not a default setting.
If the battery of a phone dies, there is certainly little power remaining to carry on power running to particular components. Many users are aware of this, however, it’s yet simply astonishing and terrifying that the M-7 managed to save tracking motion for 4 days while the user’s iPhone 5s was shut off.
By Rahad Abir