Multiplexing potentiometers

This sketch demonstrates the implementation of a multiplexer with potentiometers. You can hook up a multiplexer with a maximum of 16 channels.

NOTE: Make sure to check the datasheet of your multiplexer to determine if the default 1 microsecond switching interval is sufficient. For example, a Sparkfun CD74HC4067 running at 5 volts will probably operate fine at a switching speed of 1 microsecond. However, if you run it at 3.3 volts, it will need a switching interval of around 2 microseconds or higher. You can set this with: mux.setSwitchInterval(2). There are, however, more factors that determine how responsive your MUX is, such as signal integrity and power supply noise. Always add some decoupling capacitors to your MUX power supply and at any other place where noise might be generated.

The code

Copy#include <CtrlMux.h>
#include <CtrlPot.h>

/*
  Create a multiplexer and provide the following parameters:
  - signal pin.
  - s0 - s3: the channel select pins (s3 is optional).
*/
CtrlMux mux(A0, 2, 3, 4, 5);

// Define an onValueChange handler for pot 1
void onValueChange1(int value) {
    Serial.print("Pot 1 value: ");
    Serial.println(value);
}

// Define an onValueChange handler for pot 2
void onValueChange2(int value) {
    Serial.print("Pot 2 value: ");
    Serial.println(value);
}

// Create two potentiometers. With the: signal pin number (corresponds to the attached channel on the multiplexer),
// max. output value, sensitivity margin (can be 0.01 to 100) & onValueChange handler
// & a reference (&mux) to the multiplexer.
CtrlPot potentiometer1(0, 100, 0.5, onValueChange1, &mux);
CtrlPot potentiometer2(1, 100, 0.5, onValueChange2, &mux);

void setup() {
    Serial.begin(9600);
    mux.setSwitchInterval(2); // In microseconds.
}

void loop() {
    // The process methods will poll the potentiometer objects and handle all their functionality.
    mux.process();
}