Unknown constants!

[Texnoit-com]

Good day! Using calibrate() - the tuning resistor is turned all the way.
Decided to change the tuning constants.

There are expressions in the code:

r = pin0.read_analog()-11
r = abs(r)/900*5

What do constants mean?

• 11
• 900
• 5

[fizban99]

I am ashamed to admit that I do not remember... Anyway, in theory, read_analog returns a number between 0 and 1023, but most likely I experimentally saw that it was more between 11 and 1023. By substracting 11, the range becomes between 0 and 1012, But i probably realised that silence was a read_analog value lower than 191. This would become 180 after substracting 11. If I want any number lower than 180 to become 0, and then have steps of 180, I can fit 5 steps until 900 and then any value higher is considered top volume. So I divided by 900 and multiplied by 5 to normalize to a number between 0 and 5 to have just those volume levels. Just a guess...