I have built the circuit below using mux ICs. In a particular interval the respective selector pins get selected and analog signal from hall sensors are read and give a particular analog value out. There is a total of 30 hall sensors which are represented by HS0 to HS31.


Now I wanted to set time as in the table below. After 8000ms I would like it to reset the time automatically and start reading. Can someone tell me which timer example would let me achieve this?

TIME IS ms  OUT1    OUT2    OUT3    OUT4
  0-1000    HS0     HS8     HS16    HS24
1000-2000   HS1     HS9     HS17    HS25
2000-3000   HS2     HS10    HS18    HS26
3000-4000   HS3     HS11    HS19    HS27
4000-5000   HS4     HS12    HS20    HS28
5000-6000   HS5     HS13    HS21    HS29
6000-7000   HS6     HS14    HS22    HS30
7000-8000   HS7     HS15    HS23    HS31

1 Answer 1


Could you tell us which multiplexer IC you are using? This way, we can help you better. Also, why do you need the 8 second cycle? Does it matter if it's a little shorter or longer? If timing does not have to be very precise it would make things a lot easier.

By the way: you say there are 30 sensors, but your table has 32...

The following pseudocode will not work on your Arduino, but you can use the same structure.

int sensorArray[32] // we will store our 32 sensor values here

// these pins control the multiplexer chips
int selectPinZero = 8;
int selectPinOne = 9;
int selectPinTwo = 10;

// these pins will receive the sensor values from the multiplexer chips
int inputPinOne = 0;
int inputPinTwo = 1;
int inputPinThree = 2;
int inputPintFour = 3;

void setup(){
    // make sure the correct pins are inputs and outputs
    pinMode(selectPinZero, OUTPUT);
    pinMode(selectPinOne, OUTPUT);
    pinMode(selectPinTwo, OUTPUT);

    pinMode(inputPinOne, INPUT);
    pinMode(inputPinTwo, INPUT);
    pinMode(inputPinThree, INPUT);
    pinMode(inputPinFour, INPUT);

// all done, now keep reading the sensors
void loop(){

    // set selectPins so that each Multiplexer will output its first channel
    digitalWrite(selectPinZero, HIGH); // or low, depending on your Multiplexer IC
    digitalWrite(selectPinOne, HIGH); // or low, depending on your Multiplexer IC
    digitalWrite(selectPinTwo, HIGH); // or low, depending on your Multiplexer IC

    // start reading sensors

    int i = 0;
        sensorArray[i] = analogRead(inputPinOne);
        i++; // variable i was 0, now 1 

        sensorArray[i] = analogRead(inputPinTwo);
        i++; // variable i was 1, now 2 

        sensorArray[i] = analogRead(inputPinThree);
        i++; // variable i was 2, now 3

        sensorArray[i] = analogRead(inputPinFour);
        i++; // variable i was 3, now 4

        use digitalWrite() on all the selectPins to make the Multiplexer IC output the next channel

        delay(1000); // wait 1000 milliseconds

    this will repeat until all 32 sensors are read and stored in the array


This code is by no means optimized, but written to make it easy for you to understand. Good luck!

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