Master clock / divider & multiplier - Millis() - OLED display

My third attempt at using an Arduino to make a master clock with dividers and multipliers.

This is a good beginners circuit.

 

 

My earlier attempts are here:

+ Master clock with OLED display using the Delay function  

+ Master clock using Millis() - OLED display

 

You can of course just buy a clock multiplier / divider, but where's the fun in that.

 

i'M USING  a basic Arduino Uno

The OLED communicates via i2c

Pin	Wiring to Arduino Uno
Vin	5V
GND	GND
SCL	A5
SDA	A4

 

 

The POT is wired thus:

centre (wiper) to A0

Right to GND

Left to 5V

 

The pot supplies an analog voltage which is converted into a digital

signal by the Arduino's ADCs.

Maybe an encoder would be better used??

 

 

 

The 4 LEDs

Cathode to gnd via 220 ohm resistors

Anode to pins 8, 9, 10, 11. 

I played around with the delay function, but the Millis function works much better.

 

I'm not a coder so if you can suggest any improvements, let me know.

Feel free to hack & improve the code.

The code:

 

 // &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

/*

This is part of a project to build a Synth master clock module with multipliers and dividers

Hopefully will add MIDI later.

jondent808@gmail.com 

https://djjondent.blogspot.com/2018/03/arduino-index.html

 

*/

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

const int ledPin =  8;// the number of the LED pin 8
int ledState = LOW;             // ledState used to set the LED 8
const int ledPin9 =  9;// the number of the LED pin 9
int ledState9 = LOW;             // ledState used to set the LED 9
const int ledPin10 =  10;// the number of the LED pin 10
int ledState10 = LOW;             // ledState used to set the LED 10
const int ledPin11 =  11;// the number of the LED pin 11
int ledState11 = LOW;             // ledState used to set the LED 11

#define MIN_BPM 20      /*write here the min BPM that you want */
 #define MAX_BPM 300     /* write here the max BPM that you want */
 #define POT A0          // the potentiometer connects to analog pin A0

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// Variables
int bpm;

unsigned long previousMillis = 0;        // will store last time LED was updated
unsigned long previousMillis9 = 0;        // will store last time LED9 was updated
unsigned long previousMillis10 = 0;        // will store last time LED10 was updated
unsigned long previousMillis11 = 0;        // will store last time LED11 was updated
 
const long interval = 60000;           // interval at which to blink (milliseconds)
const long interval2 = 30000;           // interval * 2
const long interval4 = 15000;           // interval * 4
const long interval8 = 7500;           // interval * 8

void setup() {
  // set the digital pin as output:
  pinMode(ledPin, OUTPUT);
  pinMode(ledPin9, OUTPUT);
  pinMode(ledPin10, OUTPUT);
  pinMode(ledPin11, OUTPUT);
  digitalWrite(ledPin,ledState);// set initial state of pin 8 LED
  digitalWrite(ledPin9,ledState9);// set initial state of pin 9 LED
  digitalWrite(ledPin10,ledState10);// set initial state of pin 10 LED
  digitalWrite(ledPin11,ledState11);// set initial state of pin 11 LED
 
 
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C); // initialize with the I2C addr 0x3C
  display.clearDisplay(); // Clear the buffer.
}

void loop() {

   bpm = map(analogRead(POT), 0, 1023, MIN_BPM, MAX_BPM);  
    display.clearDisplay();
    display.setTextSize(3);
    display.setTextColor(WHITE);
    display.setCursor(0,0);
    display.println(bpm);
    display.setTextSize(2);
    display.setTextColor(WHITE);
    display.println("    BPM");
    display.display();
    
 
unsigned long currentMillis = millis();
unsigned long currentMillis9 = millis();
unsigned long currentMillis10 = millis();
unsigned long currentMillis11 = millis();

  if (currentMillis - previousMillis >= interval/bpm) {
    // save the last time you blinked the LED
    previousMillis = currentMillis;

    // if the LED 8 is off turn it on and vice-versa:
    if (ledState == LOW) {
      ledState = HIGH;
    } else {
      ledState = LOW;
    }
 // set the LED 8 with the ledState of the variable:
    digitalWrite(ledPin, ledState);
  }

    // **********************************
    
 if (currentMillis9 - previousMillis9 >= interval2/bpm) {
    // save the last time you blinked the LED
    previousMillis9 = currentMillis9;
    
    // if the LED 9 is off turn it on and vice-versa:
    if (ledState9 == LOW) {
      ledState9 = HIGH;
    } else {
      ledState9 = LOW;
    }
    // set the LED 9 with the ledState of the variable:
    digitalWrite(ledPin9, ledState9);
  }
  // ********************************************
      
 if (currentMillis10 - previousMillis10 >= interval4/bpm) {
    // save the last time you blinked the LED
    previousMillis10 = currentMillis10;
    
    // if the LED 10 is off turn it on and vice-versa:
    if (ledState10 == LOW) {
      ledState10 = HIGH;
    } else {
      ledState10 = LOW;
    }
    // set the LED 10 with the ledState of the variable:
    digitalWrite(ledPin10, ledState10);
  }
  //*******************************************

  if (currentMillis11 - previousMillis11 >= interval8/bpm) {
    // save the last time you blinked the LED
    previousMillis11 = currentMillis11;
    
    // if the LED 11 is off turn it on and vice-versa:
    if (ledState11 == LOW) {
      ledState11 = HIGH;
    } else {
      ledState11 = LOW;
    }
    // set the LED 11 with the ledState of the variable:
    digitalWrite(ledPin11, ledState11);
}
}

// &&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&& 

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