const byte digit_pins[3] = {5,6,7};
const byte data_pin = 2;
const byte sh_pin = 4;
const byte st_pin = 3;

unsigned long tm, next_flick, generator_flick;
const unsigned int to_flick = 1;
const unsigned int to_generator_low = 1;
const unsigned int to_generator_high = 2;
int sensorValue = 0;
float voltage = 0;

byte digit = 0;
byte is_high = 0;
unsigned int counter = 0;

const byte digits[10] = {
    B11101110,
    B10000010,
    B11011100,
    B11010110,
    B10110010,
    B01110110,
    B01111110,
    B11000010,
    B11111110,
    B11110110
};

void fill( byte d ){
    for(char i=0; i<8; i++){
        digitalWrite(sh_pin, LOW);
        digitalWrite(data_pin, digits[d] & (1«i));
        digitalWrite(sh_pin, HIGH);
    }
    digitalWrite(st_pin, HIGH);
    digitalWrite(st_pin, LOW);
}

void setDigit( byte digit, unsigned int counter ){
    byte d = 0;
    switch ( digit ){
        case 0:
        digitalWrite(digit_pins[2], LOW);
        d = counter % 10;
        fill(d);
        digitalWrite(digit_pins[0], HIGH);
        break;
        case 1:
        digitalWrite(digit_pins[0], LOW);
        d = (counter % 100) / 10;
        fill(d);
        digitalWrite(digit_pins[1], HIGH);
        break;
        case 2:
        digitalWrite(digit_pins[1], LOW);
        d = ( counter % 1000 ) / 100;
        fill(d);
        digitalWrite(digit_pins[2], HIGH);
        break;
    }
}

void setup() {
    for(int i=0; i<3; i++){
        pinMode(digit_pins[i], OUTPUT);
    }
    pinMode(data_pin, OUTPUT);
    pinMode(sh_pin, OUTPUT);
    pinMode(st_pin, OUTPUT);
    pinMode(13, OUTPUT);
    pinMode(8,OUTPUT);
    digitalWrite(8,HIGH);
    pinMode(9,OUTPUT);

}
void set_generator(byte high)
{
    if (high == 0)
        digitalWrite(9, LOW);
    if (high == 1)
        digitalWrite(9, HIGH);
}

void loop() {
    tm = millis();
    if( tm > next_flick ){
        next_flick = tm + to_flick;
        digit++;
        if( digit == 3 )
            digit = 0;
        sensorValue = analogRead(A0);
        voltage = sensorValue * (10010 / 1023.0)/10;
        setDigit( digit, voltage );
    }
    tm = millis();
    if (tm > generator_flick) {
        ++is_high;
        if (is_high == 2)
            is_high = 0;

        if (is_high == 0)
            generator_flick = tm + to_generator_low;
        else
            generator_flick = tm + to_generator_high;

        set_generator(is_high);
    }
}