If I remember correctly, EMP doesn't really work on very small devices. You need a "antenna" that is long enough to induce a strong enough current to fry your electronics. So anything connected to a long wire. The power grid is itself a huge antenna and will be completely destroyed but a small battery powered device will be unharmed.

[–] superkret@feddit.org 3 points 2 hours ago

When the power grid is down now, phones are down, the internet is down, mobile networks are down, payment systems and ATMs are down, gas stations are down, refridgeration is down, etc. etc.
Basically, 3 days later civilization is down, irreversably.

[–] hydroptic@sopuli.xyz 1 points 2 hours ago* (last edited 2 hours ago)

Lots of our battery powered devices have a bunch of literal antennas, though. I actually don't know the frequency ranges on which an EMP can be expected to "pump out" significant amounts of energy, but if there's enough in the bands where WiFi, Bluetooth, GPS etc operate that's going to fry devices that don't have some sort of protection built in. I also have no clue how common it is for radio modules used in consumer stuff to protect against voltage surges on their antennas, but somehow I'd imagine it's not very common.