Arduino Metronome

When learning a new musical instrument as a kid, there are so many new things to keep focus on. Keeping pace in the right tempo is one of them. Not finding a functionally complete and convenient metronome meant the best excuse to start building again with my kids. In this Instructables post you'll find the functional description, parts list with webshop links and prices, wiring diagram for assembly, and complete Arduino source code.

Step 1: Functional Description

It would be nice to have a metronome device with the following functions to use it at home or at the music school conveniently.

• Compact form factor to fit small places on top or next to musical instruments,
• Battery operated, robust and portable to carry around,
• Easily set up even for kids, BPM value always displayed,
• Adjustable beats per minute with a Rotary knob, up to 240 BPM
• Audible tact with volume control,
• Silent mode for overnight headphone practice,
• Visual feedback of beats (1/4, 2/4, 3/3, 4/4, 6/8, etc.) up to 8 LEDs,
• With or without leading accent, with visual and audible feedback.

Switching on, metronome mode will start at 60 BPM showing on the small display and letting the pace be tuned by the rotary knob between 10 and 240. Neopixels show the beat in blue LEDs while the buzzer ticks. Pressing the knob will switch to beat adjustment mode and green LEDs will indicate the set beat structure. Rotary knob will increment or decrement the beat structure (2/2, 3/3, 4/4, 6/8, etc.). Above 8 LEDs, further rotating clockwise, leading accent will be turned on, and the first LED will indicate this in red. Leading accent will have audible feedback as well. It can be turned off by rotating counter-clockwise. Pressing the knob will switch back from beat adjustment mode to metronome mode.

Step 2: Parts List

You will need a case. Any shape or size can be bought, but we had a nice black metal case of an old manual VGA switch disposed of a friend. The rest of the parts are listed below.

• 9V Battery, USD 1.50
• Battery connector cable, USD 0,16
• Arduino Nano with pin headers, USD 2.05
• Nano IO Extension Shield, USD 1,05
• Mini slide switch for power, USD 0.15
• Piezo buzzer, USD 0,86
• Adafruit Neopixel WS2812 8-bit, USD 1,01
• OLED Display 128x64, USD 1,53
• Rotary encoder, USD 0,50
• Dupont cables F/F, USD 0,49

Total price of the components are less than USD 10,-

Step 3: Wiring Diagram

Use the Nano IO Extension Board so as not to bother with soldering multiple GND and VCC connections. Minimal soldering will be needed for the Nano pin headers and for the Neopixel module connectors. Using Dupont wires allows stable connections for the rest of the wiring as shown on the diagram. The 9V battery is connected to GND and VIN, the latter through the power slider switch. The rotary encoder module has an integrated switch button, that is shown separately in the diagram for easier understanding of how to connect them. Rotary part (CLK and DT) is connected to PIN2 and PIN3 respectively, because these are the only NANO pins capable of Interrupt handling. Rotary GND is connected to Nano's GND PIN of course. The integrated switch button is connected to PIN4. Piezo buzzer is connected to PIN5 and GND. Adafruit Neopixel module is connected to PIN7 and its VIN and GND to Nano's 5V and GND respectively. Small OLED display is connected to the I2C bus interface, which is PIN A4 and A5 for SDA and SDL. VCC and GND goes to Nano's 5V and GND of course. That concludes our Dupont wiring.

Step 4: Arduino Source Code

The code below is incomplete because Instructables rips tags to prevent injection attacks for security reasons.
Feel free to ask the code in the comment section providing your email address.


// Metronome, Leading Accent, Visual&Audible Tact - 2019 Peter Csurgay
#include 
#include 
#include 
#include 
#include "TimerOne.h"
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
#define pin_neopixel 7
#define NUMPIXELS 8
#define BRIGHTNESS 32
Adafruit_NeoPixel pixels = Adafruit_NeoPixel(NUMPIXELS, pin_neopixel, NEO_GRB + NEO_KHZ800);
#define IDLE_11 0
#define SCLK_01 1
#define SCLK_00 2
#define SCLK_10 3
#define SDT_10 4
#define SDT_00 5
#define SDT_01 6
int state = IDLE_11;
#define CLK 2
#define DT 3
#define pin_switch 4
#define pin_buzzer 5
int bpm = 60;
int bpmFirst = 0; // LED On at First, Off at the rest...
int tack = 4;
bool leadingTack = false;
int pos = 0;
int curVal = 0;
int prevVal = 0;

void setup() {
  pixels.begin();
  pinMode(pin_buzzer, OUTPUT);
  Timer1.initialize(1000000*60/bpm/2);
  Timer1.attachInterrupt(buzztick);
  pinMode(CLK, INPUT_PULLUP);
  pinMode(DT, INPUT_PULLUP);
  pinMode(pin_switch, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(CLK), rotaryCLK, CHANGE);
  attachInterrupt(digitalPinToInterrupt(DT), rotaryDT, CHANGE);
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3D for 128x64
    for(;;); // Don't proceed, loop forever
  }
  display.clearDisplay();
  display.display();
}

void loop() {
  if (digitalRead(pin_switch)==LOW) {
    delay(100);
    while(digitalRead(pin_switch)==LOW) ;
    delay(100);
    Timer1.detachInterrupt();
    showGreenTacks();
    while(digitalRead(pin_switch)==HIGH) {
      if (curVal>prevVal) {
        tack+=1; if (tack>8) { if (leadingTack) tack = 8; else { leadingTack = true; tack = 1; } }
      } else if (curValprevVal) {
    bpm+=2; if (bpm>240) bpm = 240;
  } else if (curVal=100) display.print("       "); else display.print("        "); 
  display.print(bpm);
  display.display();
}

void buzztick() {
  if (bpmFirst==0) {
    int volume = 4; if (leadingTack && pos==0) volume = 8;
    for (int i=0; i

Comments

[francisco35363]

Bonsoir,
Projet très intéressant et je voudrais en fabriquer un similaire.
Est-il possible d'avoir le code arduino complet ?
Merci d'avance
FD

[csurgay]

Hello FD, for me to send you the code I will need your email address.

[francisco35363]

[e-mail]

[enricolatalpa]

Hi very nice project. Can you send e your code? Thanks in advance.
[e-mail]

[zxbdavidmarshal]

Hi! Great Job! Its a very interesting project. Would be possible to get the source code?
[e-mail]
Thanks in advance!

[Tankman]

Hello,
This project seems very interesting and I would to try it.
Would it be possible to get the source code ?
email : [e-mail]
Thanks a lot

[marcospitra]

Hi! Great Job! Its a very interesting project. Would be possible to get the source code? [e-mail].
Thanks in advance!

[Dirpy]

Hello,
This project seems very interesting and I would love to try, would it be possible to get the source code ?
email : [e-mail]
Thanks a lot

[Allan_D_Murray]

Hi,
I would like to build this project. Can I also get the source code please?
[e-mail]
Cheers!

[Kevin-KT]

Hi, I really like your design project and I would love to make it. However the code isn't working. I would love to ask if you could send me the code please? email is [e-mail]. Thank you.

[HINI.GOE]

Hello, i like your project because its very detailed but i would need the full code to get it done. Im trying to make a full led strip blinking as metronome/strobe light. DO you think that would be possible with your code too? I hope i'll her from you. Best regards

[HINI.GOE]

My email is [e-mail]. Again Best regards :)

[power32]

Kedves Péter! Én is egy hasonló metronómot készítenék, csak elakadtam abban, hogy átszámoljam a bpm-et. Arra kérném, hogy ebben legyen szíves segíteni, ha nem nagy kérés. Előre is köszönöm!

[csurgay]

Nagyon szívesen, hol tudjuk megbeszélni, email/skype/viber?

[power32]

Köszönöm a válaszodat :-) az email címem: [e-mail]

[un7gdz]

Hello, I want to do the Great project, can you send me the code at:
[e-mail]

[m.77.heurtevent]

Hi, I really want to do the project, can you send me the code at:
[e-mail]

[paulmckenna]

Hi, This looks like a really interesting project that I would like to make. I have bought the components. It's a shame the code in Step 4 is incomplete. Please could you post or send me the complete Arduino code. Many thanks.

email: [e-mail]

[lil.dema93]

Hello. I really want to repeat your project. I would be grateful if you share the source code. Thank you in advance.

[sergeus898]

Excellent project. Thank you for sharing them!
Can you send me, please, full Arduino code?
[e-mail]