Pot --> Mux --> MCU --> Servos???

Other Hardware LEDs and Multiplexing
1

I'm not sure how to write the code to get the MCU to look at each of the "channels", convert that info to a PWM and send it out to the servos.

I was going to combine the analog input mux code with the "servo knob" example code.

Here is the mux code I'm using:

//Mux control pins
int s0 = 10;
int s1 = 11;
int s2 = 13;
int s3 = 14;

//Mux in "SIG" pin
int SIG_pin = 0;

void setup(){
  pinMode(s0, OUTPUT);
  pinMode(s1, OUTPUT);
  pinMode(s2, OUTPUT);
  pinMode(s3, OUTPUT); 

  digitalWrite(s0, LOW);
  digitalWrite(s1, LOW);
  digitalWrite(s2, LOW);
  digitalWrite(s3, LOW);

  Serial.begin(9600);
}

void loop(){

  //Loop through and read all 16 values
  //Reports back Value at channel 6 is: 346
  for(int i = 0; i < 16; i ++){
    Serial.print("Value at channel ");
    Serial.print(i);
    Serial.print("is : ");
    Serial.println(readMux(i));
    delay(100);
  }

}

int readMux(int channel){
  int controlPin[] = {s0, s1, s2, s3};

  int muxChannel[16][4]={
    {0,0,0,0}, //channel 0
    {1,0,0,0}, //channel 1
    {0,1,0,0}, //channel 2
    {1,1,0,0}, //channel 3
    {0,0,1,0}, //channel 4
    {1,0,1,0}, //channel 5
    {0,1,1,0}, //channel 6
    {1,1,1,0}, //channel 7
    {0,0,0,1}, //channel 8
    {1,0,0,1}, //channel 9
    {0,1,0,1}, //channel 10
    {1,1,0,1}, //channel 11
    {0,0,1,1}, //channel 12
    {1,0,1,1}, //channel 13
    {0,1,1,1}, //channel 14
    {1,1,1,1}  //channel 15
  };

  //loop through the 4 sig
  for(int i = 0; i < 4; i ++){
    digitalWrite(controlPin[i], muxChannel[channel][i]);
  }

  //read the value at the SIG pin
  int val = analogRead(SIG_pin);

  //return the value
  return val;
}

...and here is the "servo knob" example code that everyone has:

// Controlling a servo position using a potentiometer (variable resistor) 
// by Michal Rinott <http://people.interaction-ivrea.it/m.rinott> 

// NOTE: UART will be disabled when servo is attached to pin 0 or 1.


#include <Servo.h> 

 
Servo myservo;  // create servo object to control a servo 
 
int potpin = 0;  // analog pin used to connect the potentiometer
int val;    // variable to read the value from the analog pin 
 
void setup() 
{ 
  myservo.attach(9);  // attaches the servo on pin 9 to the servo object 
} 
 
void loop() 
{ 
  val = analogRead(potpin);            // reads the value of the potentiometer (value between 0 and 1023) 
  val = map(val, 0, 1023, 0, 179);     // scale it to use it with the servo (value between 0 and 180) 
  myservo.write(val);                  // sets the servo position according to the scaled value 
  delay(15);                           // waits for the servo to get there 
}

Also, I plan on using 6 muxes, how do I get it to look at the different "sig" pins?

Thanks, I'm new. :slight_smile:

2

So you have 6 16-channel MUX's connected to the 6 analog input pins? That's 96 input values.

How do you connect the 96 servos?!?

3

Right, I'm not going to be able to use all of the muxes, any help with the actual question?

4

tt_tony:
Right, I'm not going to be able to use all of the muxes, any help with the actual question?

Change readMux() to take both the current mux address (0-15) and an analog input pin (0-5).

Use readMux(muxChannel, analogPin) in place of analogRead(potpin) in the Servo Knob example. For each combination of muxChannel and analogPin you'll need a Servo object. I'd put them in an array for easy access.

Servo servoTable[96];
5

thanks for that John, I'll try it tonight. When I was buying the multiplexers I forgot that I wasnt going to be able to use all 83 of my pins. I guess if i ever get to that point that I would need as many servos as possible I could use one board as a transmitter and two as receivers.