Hello all,
I am working on a project to record/analyze low-frequency noise with a Pi Zero. Currently early in the prototyping stage, so want to see whether this plan seems feasible:
which would connect to...
I guess would need a custom op-amp circuit to go from mic level to line level (looks like that mic outputs at 0.355 Vrms at 200Ω impedance; not sure how close that is to line-readable).
which would feed...
The line input on a Audio Injector Zero Sound Card. (Planning to use line in even if it needs amp rather than mic input because future versions might require two channels.)
I am pretty comfortable with basic digital work and programming, but this is one of my first forays into the analog world. So my questions are:
1. Does this seem like a reasonable approach overall?
2. Does anyone know of a MEMS microphone with extended low-frequency response that outputs I2S or otherwise digital, as that would save some design headache obviously? (My target sounds are 20-150 Hz.)
3. Is there a built-in highpass filter in the Audio Injector Zero card that would limit input performance in the 20-150 Hz range?
5. Other general advice?
Thanks very much,
John