im trying to read a guitar signal using a mcp6002 opamp to amplify the signal,
schematic taken from this project:
https://www.electrosmash.com/arduino-audio-meter
im using a stm32f411 blackpill board and ili9341 touchscreen,
the voltage on pin A0 bounces around 1.75volts - 1.82volts wether I play the guitar strings or not,
my meter moves, but not how I want it to move,
I previously did this using an lm386 opamp, an led and ldr that gave me 0=5volts with this code:
if (millis() - updateTime >= analogReadInterval)
{
updateTime += analogReadInterval;
int raw = analogRead(PA0);
reading = map(raw, 0, 1024, 0, 100);
if (meterOn == true)
plotNeedle(reading, 0); // Draw needle
how can I map the mcp6002 voltage to make the needle move like not playing strings = needle fully left, and playing strings hard = needle fully right?
