Re: S Meter Nextion 3.2

Jerry Gaffke

Monitoring the control voltage of an added AGC circuit or the output of a logarithmic detector such as the AD8307
can give a useful S-meter indication. 
A diode detector on the audio read by a 10 bit ADC will have severely limited dynamic range,
a max of 3 S-units assuming the logarithmic conversion is carried out in firmware.

On Sun, Oct 20, 2019 at 02:12 AM, Vic WA4THR wrote:
The S-meter requires an external circuit to supply the signal level information. There are several choices ranging from a simple diode detector all the way up to a more complicated second Arduino chip. Take a look at the KD8CEC website as he describes several easily wired circuits. I started with an LM386 amp and detector that connects between the volume pot and a spare Raduino input, and that worked very well. I later replaced that with the second Arduino to get some additional features.

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