zlacker

From a hardware point of view I've also noticed that speakers work like poor microphones (and LEDs like poor solar panels / light sensors), but is there any way to actually make this work on most devices without physically changing wiring? If the circuits aren't made to take measurements (or the software can't get at the readings) but only set a voltage on the wires, there wouldn't be a way to (ab)use this. I don't know enough about electronics to know whether this is commonly the case

Not that it's not a good thing to be aware of, but do you have any sort of source for what kinds of devices can have their speakers turned into microphones? Then I'll believe you about the government part

>>Aachen+(OP)
I don’t think they meant literally “any” but more like a device with a speaker could be delivered to you that has a speaker/microphone. Like a Bluetooth speaker you order of the internet. It seems it would probably have to be personally targeted to you, but in that case, there are probably simpler ways.

>>Aachen+(OP)
Many a soundcard supports changing jack "direction". Here's a StackExchange answer from 2012, on how to do it with the GUI tool `hdajackretask` : https://askubuntu.com/a/911961

>>Aachen+(OP)
Any was an exaggeration and less than honest on my part, I apologize. I think the speakers in most smart devices though can because they have the circuitry as another comment mentioned to record the input in reverse via software.

I think most speakers would have that today, most modern speakers. Plain speakers that just take a voltage signal though, probably not. Though how many people use those kinds of speakers today I wonder.