The iPhone 5s M7 chip counts your steps even after the battery dies

Most of you know that the iPhone 5s has a motion coprocessor called the M7 chip that keeps track of your motion related data derived from the integrated accelerometer, gyroscope and compass sensors. But did you know that this data is collected even while your iPhone’s battery has died?

When an iPhone shuts down due to low battery, its battery isn’t completely drained, and it appears that the M7’s power usage is so low that Apple let it run even in this state. So the M7 chip, and the associated sensors continue collecting data to compute your steps and other motion related activity.

And since the M7 coprocessor works independently of the CPU, it doesn’t require other components of the iPhone to be powered on.

This tidbit was found by a reddit user, who wrote: 

While traveling abroad, my iPhone cable stopped working so my 5s died completely.

I frequently use Argus to track my steps (highly recommended if you have any health bands or accessories) since it takes advantage of the M7 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 4 days that my phone was dead.

I’m both incredibly impressed and slightly terrified.

While this might raise some privacy alarms, it’s important to note that the M7 chip doesn’t collection your actual location, just the motion related data from the three sensors.

Let us know in the comments what you think about this tidbit. Privacy violation or a cool feature?