Project Idea?

[Rescurat]

Looking for ideas regarding a project. I would like to build a circuit that allows 2 or more inputs to be combined, iphone and 2-way radio for example with priority channel override.

 

[ChrisP58]

An audio mixer is an easy circuit. Just an op-amp configured as a summing amp.

For priority override, you would add a precision rectifier and a level detector feed from the priority channel, and use it's output to mute or attenuate the secondary channels.

 

[dr pepper]

Depending on how the radio is powered, if the iphone is to be charged from a mains charger at the same time its connected to this circuit, you might want to isolate the audio out from the phone, there is often a small capacitance from the mains to the o/p of a phone charger to prevent rf interference, this might upset a 2 way radio, esp lower frequency ones.
If you can find one an LT44 might do the job, or one of these car radio ground loop isolators.