It is time. I’ve started working on eagle (I swore I would use kicad but…) again on the developer kit for the future. But my electrical engineering skills are lacking especially when it comes to analog.
I want to use the SAMD21 for the basis of the new hardware, but I’m having some trouble trying to decide how to handle the audio.
The setup should have both input and output. Here is a list of options I’ve thought about:
- Connecting the ADC and DAC pins directly to the mic and speaker. (Basically how things are implemented currently)
- Adding some filtering to the above scenario
- Adding just a single output transistor to the speaker with the filters
- Using some class of amplifier circuit to deliver proper line level and quality speaker output
- Using dedicated amplifier IC
- Using I2S audio chip for input and output
In general I’ve never worked with microphones so I’m not sure what kind of levels if just tying it to an ADC channel would even work at all. I’m guessing you might need an amplifier going into the input as well?
So i could use help evaluating which on of these directions to go, and then once that is decided some help in developing the circuit. People are picky about audio I want to get it right, and I realize it was a weak spot on the last hardware.
I’d like to put in an actual speaker, and an audio jack also.
Audio techs, assemble!