Play Music with the Chip Trombone

A fun little musical instrument that plays tones and changes speed while moving your hands up and down.

BeginnerFull instructions provided1 hour551

Things used in this project

Hardware components

Texas Instruments EK-TM4C123GXL TM4C Tiva LaunchPad

Seeed Studio Grove Starter Kit for LaunchPad

x1 Grove Base BoosterPack x2 Ultrasonic Rangers (D) x1 Buzzer (D) x1 4-Digital-Display (D) x4 Grove Cables

Software apps and online services

Texas Instruments Energia

Story

Origin

While the Chip Trombone was not originally in our creation palette, we transitioned to creating sound from taking sound in. Instead of creating a device that registered the note of whatever was being played in the surrounding area (like a tuner), we opted in creating a more simplified model of the theremin, a musical instrument that measures the distance between your hands and the device to create sound. The end result would be more fun to play with!

Overview

The Chip Trombone will register both your hands for different purposes: one hand will register distance to create a note while your other hand will be used to control the duration of the note. You can play music using the Chip Trombone and if you familiarize yourself with the device, you can learn to play more difficult music!

How does it work?

As mentioned previously, one ultrasonic ranger outputs pitch while another outputs note duration. The four-digit-display is connected to the ultrasonic ranger that outputs pitch in order to more closely simulate a sort of range instruments have. In our case, however, a farther distance will create a lower pitch and a slower note duration.

Hazards Ahead!

We started off with testing one ultrasonic ranger and the buzzer, and we programmed it to play lower frequencies at smaller distances and higher frequency tones when your hand was far away. All was working well, until we took our hand out of range... the buzzer would still buzz! This is because the ranger was still detecting the ceiling! We easily fixed this by creating a limit to what detected distance would play a tone, 3 meters, less than the ceiling but far enough for our long-armed friends. There needs to be a distance threshold otherwise the ultrasonic rangers will pick up ceilings!

Adding a Second Ultrasonic Ranger

Our next step was to add a second ultrasonic ranger in order to allow us to vary the speed of the note, aka the duration, using another hand. Again, we set a limit for the distance, so the ceiling wouldn’t affect the music. We also decided to create a default duration of 250 “beats” in case you just wanted to use one hand/one ultrasonic ranger.

Chip Trombone Setup

We finally finished the Chip Trombone! Now you can decently play those annoying recorder songs you had to memorize in 4th grade! You can even modify this project to add more rangers and buzzers to create a whole band!

Code

ELEC 220 Chip Trombone

#include "TM1637.h" 
#include "Ultrasonic.h"
/* Macro Define */
/* Set pins for all the components*/
#define CLK               39              /* 4-Digit Display clock pin */
#define DIO               38              /* 4-Digit Display data pin */
#define ULTRASONIC_PIN    24              /* pin of the Ultrasonic Ranger */
#define BUZZER_PIN        36              /* sig pin of the Grove Buzzer */

/* Global Variables */
TM1637 tm1637(CLK, DIO);                  /* 4-Digit Display object */
Ultrasonic ultrasonic(ULTRASONIC_PIN);    /* Ultrasonic Ranger object */
Ultrasonic ultra2(26);
int distance = 0;                         /* variable to store the distance to obstacles in front */
int durDis = 0;
int8_t bits[4] = {0};                     /* array to store the single bits of the value */

/* the setup() method runs once, when the sketch starts */
void setup() 
{
    /* Initialize 4-Digit Display */
    tm1637.init();
    tm1637.set(BRIGHT_TYPICAL);
    pinMode(BUZZER_PIN, OUTPUT);
}

/* play tone */
void playTone(int tone, int duration) 
{
  for (long i = 0; i < duration * 1000L; i += tone * 2) 
  {
    digitalWrite(BUZZER_PIN, HIGH);
    delayMicroseconds(tone);
    digitalWrite(BUZZER_PIN, LOW);
    delayMicroseconds(tone);
  }
}

/* the loop() method runs over and over again */
void loop()
{
    distance = ultrasonic.MeasureInCentimeters();   /* read the value from the sensor */  
    durDis = ultra2.MeasureInCentimeters();
    
    memset(bits, 0, 4);                             /* reset array before we use it */
    int altDis = distance;
    for(int i = 3; i >= 0; i--) 
    {
        /* Convert the value to individual decimal digits for display */
        bits[i] = altDis % 10;
        altDis = altDis / 10;
        tm1637.display(i, bits[i]);                 /* display on 4-Digit Display */
    }
    /* set a distance threshold up to where the ultrasonic rangers will register        hand placement*/
    if (distance < 100) {
      if (durDis < 100) {
        playTone(900 + 20*distance, 250 + 20* durDis);  /*plays at a frequency*/
        
      }
      else {
        playTone(900 + 20*distance, 250); /*playes at a frequency with default 
                                            duration*/
      }
    }   
    delay(10);
}

Credits

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Play Music with the Chip Trombone