Oh Gurus of sound, a little guidance please.

Other Hardware Audio
1

Hi, I want to use my icom air band VHF transceiver IC-A110E to transmit mp3 or wav audio files of voice recordings. I am using a 3.3V 8Mhz pro-mini, and want to interface with Adafruits VS1053 MP3/AAC/Ogg/MIDI/WAV Codec Breakout. They have a library and I am a dummy, so it looks like a good start.

The VHF transceiver has an electret condenser microphone with RJ45 connector.

A rudimentary way would be to hook up the codec to an amplifier and speaker and put the microphone in front of the speaker. But I'm hoping a more elegant solution might be possible. Is their a way of taking the analogue output from the codec and somehow conditioning the signal to have the same characteristics as the output from the electret microphone. This way I could dispense with the microphone and plug my output into the RJ45 mike connection.

I know nothing about sound, but have a little experience with RF.

Cheers

Matt.

2

Yes that's feasible, you'd have to know the level it expects from the electret, but a simple voltage divider and
dc-blocking capacitor should be enough to do this. If the codec module outputs PWM or class-D, you'll need
an RC low-pass filter too.

3

Playing recordings on the air band is probably illegal.

Pete

4

el_supremo:
Playing recordings on the air band is probably illegal.

Not if you have a licence.

Thanks for the advice, Mark. Having slept on it I came to the same conclusion. The codec output is analogue, so a voltage divider to attenuate the signal and a DC blocking cap to block GBUF should do it. If I use a pot for the voltage divider I should be able to start from zero and dial it up until the signal can be heard.

Cheers

Matt.