1.FilteredAnalog.ino

1.FilteredAnalog

This examples shows how to filter an analog input, so you can get the position of a knob or fader without noise.

Boards:

AVR, AVR USB, Nano Every, Nano 33 IoT, Nano 33 BLE, Due, Teensy 3.x, ESP8266, ESP32

Connections

• A0: wiper of a potentiometer

Connect the left terminal of the potentiometer to ground, and the right one to V_CC.

Behavior

• Upload the sketch to the Arduino, and open the Serial Monitor (CTRL+Shift+M)
• When you turn the potentiometer, you should see the position of the potentiometer being printed as a number between 0 and 1023.
• The analog input is filtered, so there shouldn't be any noise on the position. If there is, check your wiring, and make sure that the resistance of the potentiometer isn't too high (10 kΩ is ideal).

The example 1.FilteredAnalog-Advanced.ino has more information about the parameters you can pass to the FilteredAnalog class to tweak the filters, increase the resolution, etc.

Written by PieterP, 2019-10-10
https://github.com/tttapa/Arduino-Filters

 
// Include the library
#include <Filters.h>
 
#include <AH/Hardware/FilteredAnalog.hpp>
#include <AH/Timing/MillisMicrosTimer.hpp>
 
// Create a filtered analog object on pin A0, with the default settings:
FilteredAnalog<> analog = A0;
 
void setup() {
  Serial.begin(115200);
  while (!Serial);
  // Select the correct ADC resolution
  analog.setupADC();
  // Initialize the filter to whatever the value on the input is right now
  // (otherwise, the filter is initialized to zero and you get transients)
  analog.resetToCurrentValue();
}
 
void loop() {
  // Read the analog input every millisecond, and print if the value has changed
  static Timer<millis> timer = 1; // ms
  if (timer && analog.update())
    Serial.println(analog.getValue());
}
 
// Explanation:
//
// analog.update() reads the analog input, applies the filters,
// saves the value, and returns true if the value has changed.
// You can then retreive the new value using analog.getValue().
//
// Timer is just a "Blink Without Delay" wrapper, it returns true
// every time the specified amount of time has passed.