I have a Plasma Ball with a built in microphone and would like to add another switch S1 and an audio-in port to the circuit J1. How do I calculate the line attenuation R1 and R2 resistors?
My idea is to add another switch S1 so I can switch between using the internal Microphone MIC1 or use the audio-in from an external source J1. Is this the best way to do this?
Some questions I have are:
1) Do I need to use a shielded wire for the microphone MIC1 when I move it or when I add the audio-in input J1? I would like the plasma ball not to fry these components or the devices they are connected to.
2) Also how would I calculate the (resistors) R1 and R2 to limit the voltage that comes in from the audio-in jack? J1 my audio input would be around 343mV
See image of circuit board with built-in microphone circled in RED along with schematic of what I want to change / add to the circuit.
I tried using the built in circuit builder to electronics stackexchange below but it was missing some objects
Input: 100-240v 50/60hz, 0.18A max
Output: 12V 500mA