Speaker and Microphone


#1

Hi there
I’m new to KiCad and i wanted to create a PCB with a LED Stripe, Microphone and a Speaker fully controlled via (WiFi) TCP to a Server.
I use a ATMega 162-M
Currently I have set up everything but i have problems with the Speaker and Microphone.
Does anyone know if I can directly plug the Microphone and Speaker to the ATMega? Or do I need resistors and capacitors? If yes, what do you recommend?

Thank you
cacciu


#2


or
http://www.avrfreaks.net/
or (in case you are fluent in reading/understanding German)
http://www.mikrocontroller.net/


#4

ATMega does not have a DAC and only a basic ADC.


#5

This could be easy emulated by single channel PWM or dual channel PWM signal (>50Ohm speaker with small enclosure could be connected directly); from internal counter.

Bare microphone should be amplified to get a minimum 1Vpp analog signal. There are some MEMS microphones with SPI output, so ADC will not be necessary.
By the way. Build in analog converter has also limited speed. So max. frequency response is low. IMO worse than AM radio.


#6

I have used the PWM to generate 50Hz sinewaves. Not so easy for even AM quality audio. As @cacciu also needs a TCP stack, I wonder if an ATMega, rather than a cheap 32 bit like AVR32 C series or STM32 is the best starting choice