I'd like to add 2 physical switches to my iPhone and read their values in an app then do things based on those inputs.

I understand the iPhone will detect an external mic if it sees a 1600 ohm impedance on the mic channel of the TRRS plug.

I was thinking I'd play 2 different tones on the left and right audio channels. I'll feed left and right to different SPST momentary switches, with the other side of the switches feeding to a common 1.6K resistance which in turn leads to the mic on the 4 pole headphone plug.

What stupid mistakes am I making with this idea?

Electrically I don't think I'm going to break anything with this, accoustically there's going to be some great big pops every time a switch contact closes but this audio will never be played to anyone.

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