Posts with «capacitance» label

Arduino BeatBox

Create your very own Arduino BeatBox !

Home-made capacitive touch sensors are used to trigger the MP3 drum sounds stored on the Grove Serial MP3 player. I have used a number of tricks to get the most out of this module, and I was quite impressed on how well it did. Over 130 sounds were loaded onto the SDHC card. Most were drum sounds, but I added some farm animal noises to provide an extra element of surprise and entertainment. You can put any sounds you want on the module and play them back quickly. We'll put the Grove Serial MP3 module through it's paces and make it into a neat little BeatBox !!

Key learning objectives

How to make your own beatbox
How to make capacitive drum pad sensors without using resistors
How to speed up Arduino's Analog readings for better performance
How to generate random numbers on your Arduino

Parts Required:

Arduino UNO or compatible board
Grove Base Shield
Grove Serial MP3 Player
Grove Sliding Potentiometer
Grove Button or Grove Button (P)
Grove Universal 4 pin cables
Battery Holder
SanDisk 8GB Ultra Micro SDHC Memory card
Portable Powered Speaker or Headphones
4 LEDs - 1 x Green, 1 x Blue, 1 x Red and 1 x Yellow
A shoe box, paper, aluminum foil, scissors, glue etc. etc.

Making the drum pads

Fritzing Sketch

Grove Connections

Grove Connections (without base shield)

Arduino Sketch


/* =================================================================================================
      Project: Arduino Beatbox
       Author: Scott C
      Created: 9th April 2015
  Arduino IDE: 1.6.2
      Website: http://arduinobasics.blogspot.com/p/arduino-basics-projects-page.html
  Description: This project uses home made capacitive sensors to trigger over 130 MP3 sounds
               on the Grove Serial MP3 player. 
               
               The ADCTouch library is used to eliminate the resistors from the Capacitive sensing circuit. 
               The code used for capacitive sensing was adapted from the ADCTouch library example sketches. 
               You can find the ADCTouch library and relevant example code here:
               http://playground.arduino.cc/Code/ADCTouch
               
               "Advanced Arduino ADC" is used to improve the analogRead() speed, and enhance the
               drum pad or capacitive sensor response time. The Advanced Arduino ADC code 
               was adapted from this site:
               http://www.microsmart.co.za/technical/2014/03/01/advanced-arduino-adc/
               
               
=================================================================================================== */
  #include <ADCTouch.h>
  #include <SoftwareSerial.h>
  
  
  //Global variables
  //===================================================================================================
  int potPin = A4;                           //Grove Sliding potentiometer is connected to Analog Pin 4
  int potVal = 0;
  byte mp3Vol = 0;                           //Variable used to control the volume of the MP3 player
  byte oldVol = 0;
  
  int buttonPin = 5;                         //Grove Button is connected to Digital Pin 5
  int buttonStatus = 0;
  
  byte SongNum[4] = {0x01,0x02,0x03,0x04};  //The first 4 songs will be assigned to the drum pads upon initialisation
  byte numOfSongs = 130;                    //Total number of MP3 songs/sounds loaded onto the SDHC card
  
  long randNumber;                          //Variable used to hold the random number - used to randomise the sounds.
  
  int ledState[4];                          //Used to keep track of the status of all LEDs (on or off)
  int counter = 0;
  
  SoftwareSerial mp3(3, 4);                 // The Grove MP3 Player is connected to Arduino digital Pin 3 and 4 (Serial communication)
       
  int ref0, ref1, ref2, ref3;               //reference values to remove offset
  int threshold = 100;
      
  // Define the ADC prescalers
  const unsigned char PS_64 = (1 << ADPS2) | (1 << ADPS1);
  const unsigned char PS_128 = (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0);
  
  
  
  //Setup()
  //===================================================================================================
  void setup(){
    //Initialise the Grove MP3 Module
    delay(2500);                              //Allow the MP3 module to power up        
    mp3.begin(9600);                          //Begin Serial communication with the MP3 module
    setPlayMode(0x00);                        //0x00 = Single song - played once ie. not repeated.  (default)
    
    //Define the Grove Button as an INPUT
    pinMode(buttonPin, INPUT);
    
    //Define the 4 LED Pins as OUTPUTs
    pinMode(8, OUTPUT);                       //Green LED
    pinMode(9, OUTPUT);                       //Blue LED
    pinMode(10, OUTPUT);                      //Red LED
    pinMode(11, OUTPUT);                      //Yellow LED
    
    //Make sure each LED is OFF, and store the state of the LED into a variable.
    for(int i=8;i<12;i++){
      digitalWrite(i, LOW);
      ledState[i-8]=0;
    } 
    
    //Double our clock speed from 125 kHz to 250 kHz
    ADCSRA &= ~PS_128;   // set up the ADC
    ADCSRA |= PS_64;    // set our own prescaler to 64 
    
    //Create reference values to account for the capacitance of each pad.
    ref0 = ADCTouch.read(A0, 500);
    ref1 = ADCTouch.read(A1, 500);      //Take 500 readings
    ref2 = ADCTouch.read(A2, 500);
    ref3 = ADCTouch.read(A3, 500);
    
     //This helps to randomise the drum pads.
     randomSeed(analogRead(0));
  }
  
  
  
  // Loop()
  //===================================================================================================     
  void loop(){
     
    //Take a reading from the Grove Sliding Potentiometer, and set volume accordingly
    potVal = analogRead(potPin);
    mp3Vol = map(potVal, 0, 1023, 0,31);              // Convert the potentometer reading (0 - 1023) to fit within the MP3 player's Volume range (0 - 31)
    if((mp3Vol>(oldVol+1))|(mp3Vol<(oldVol-1))){      // Only make a change to the Volume on the Grove MP3 player when the potentiometer value changes
      oldVol = mp3Vol;
      setVolume(mp3Vol);
      delay(10);                                      // This delay is necessary with Serial communication to MP3 player
    }
    
    //Take a reading from the Pin attached to the Grove Button. If pressed, randomise the MP3 songs/sounds for each drum pad, and make the LEDs blink randomly.
    buttonStatus = digitalRead(buttonPin);
    if(buttonStatus==HIGH){
      SongNum[0]=randomSongChooser(1, 30);
      SongNum[1]=randomSongChooser(31, 60);
      SongNum[2]=randomSongChooser(61, 86);
      SongNum[3]=randomSongChooser(87, (int)numOfSongs);
      randomLEDBlink();
    }
    
    //Get the capacitive readings from each drum pad: 50 readings are taken from each pad. (default is 100) 
    int value0 = ADCTouch.read(A0,50);        //  Green drum pad
    int value1 = ADCTouch.read(A1,50);        //   Blue drum pad
    int value2 = ADCTouch.read(A2,50);        //    Red drum pad
    int value3 = ADCTouch.read(A3,50);        // Yellow drum pad
    
    //Remove the offset to account for the baseline capacitance of each pad.
    value0 -= ref0;       
    value1 -= ref1;
    value2 -= ref2;
    value3 -= ref3;
    
    
    //If any of the values exceed the designated threshold, then play the song/sound associated with that drum pad.
    //The associated LED will stay on for the whole time the drum pad is pressed, providing the value remains above the threshold. 
    //The LED will turn off when the pad is not being touched or pressed.
    if(value0>threshold){
      digitalWrite(8, HIGH);
      playSong(00,SongNum[0]);
    }else{
      digitalWrite(8,LOW);
    }
    
    if(value1>threshold){
      digitalWrite(9, HIGH);
      playSong(00,SongNum[1]);
    }else{
      digitalWrite(9,LOW);
    }
    
    if(value2>threshold){
      digitalWrite(10, HIGH);
      playSong(00,SongNum[2]);
    }else{
      digitalWrite(10,LOW);
    }
    
    if(value3>threshold){
      digitalWrite(11, HIGH);
      playSong(00,SongNum[3]);
    }else{
      digitalWrite(11,LOW);
    }
  }
      
   
  // writeToMP3: 
  // a generic function that simplifies each of the methods used to control the Grove MP3 Player
  //===================================================================================================
  void writeToMP3(byte MsgLEN, byte A, byte B, byte C, byte D, byte E, byte F){
    byte codeMsg[] = {MsgLEN, A,B,C,D,E,F};
    mp3.write(0x7E);                        //Start Code for every command = 0x7E
    for(byte i = 0; i<MsgLEN+1; i++){
      mp3.write(codeMsg[i]);                //Send the rest of the command to the GROVE MP3 player
    }
  }
  
  
  //setPlayMode: defines how each song is to be played
  //===================================================================================================
  void setPlayMode(byte playMode){
    /* playMode options:
          0x00 = Single song - played only once ie. not repeated.  (default)
          0x01 = Single song - cycled ie. repeats over and over.
          0x02 = All songs - cycled 
          0x03 = play songs randomly                                           */
    writeToMP3(0x03, 0xA9, playMode, 0x7E, 0x00, 0x00, 0x00);  
  }
  
  
  //playSong: tells the Grove MP3 player to play the song/sound, and also which song/sound to play
  //===================================================================================================
  void playSong(byte songHbyte, byte songLbyte){
    writeToMP3(0x04, 0xA0, songHbyte, songLbyte, 0x7E, 0x00, 0x00);            
    delay(100);
  }
  
  
  //setVolume: changes the Grove MP3 player's volume to the designated level (0 to 31)
  //===================================================================================================
  void setVolume(byte Volume){
    byte tempVol = constrain(Volume, 0, 31);             //Volume range = 00 (muted) to 31 (max volume)
    writeToMP3(0x03, 0xA7, tempVol, 0x7E, 0x00, 0x00, 0x00); 
  }
  
  
  //randomSongChooser: chooses a random song to play. The range of songs to choose from
  //is limited and defined by the startSong and endSong parameters.
  //===================================================================================================
  byte randomSongChooser(int startSong, int endSong){
    randNumber = random(startSong, endSong);
    return((byte) randNumber);
  }
  
  
  //randomLEDBlink: makes each LED blink randomly. The LEDs are attached to digital pins 8 to 12.
  //===================================================================================================
  void randomLEDBlink(){
   counter=8;
   for(int i=0; i<40; i++){
     int x = constrain((int)random(8,12),8,12);
     toggleLED(x);
     delay(random(50,100-i));
   }
     
    for(int i=8;i<12;i++){
      digitalWrite(i, HIGH);
    }
    delay(1000);
    for(int i=8;i<12;i++){
      digitalWrite(i, LOW);
      ledState[i-8]=0;
    }
  }
  
  
  //toggleLED: is used by the randomLEDBlink method to turn each LED on and off (randomly).
  //===================================================================================================
  void toggleLED(int pinNum){
    ledState[pinNum-8]= !ledState[pinNum-8];
    digitalWrite(pinNum, ledState[pinNum-8]);
  }

Arduino Code Discussion

You can see from the Arduino code above, that it uses the ADCTouch library. This library was chosen over the Capacitive Sensing Library to eliminate the need for a high value resistor which are commonly found in Capacitive Sensing projects).

To increase the speed of the Analog readings, I utilised one of the "Advanced Arduino ADC" techniques described by Guy van den Berg on this Microsmart website.

The readings are increased by modifying the Arduino's ADC clock speed from 125kHz to 250 kHz. I did notice an overall better response time with this modification. However, the Grove Serial MP3 player is limited by it's inability to play more than one song or sound at a time. This means that if you hit another drum pad while the current sound is playing, it will stop playing the current sound, and then play the selected sound. The speed at which it can perform this task was quite impressive. In fact it was much better than I thought it would be. But if you are looking for polyphonic playability, you will be dissapointed.

This Serial MP3 module makes use of a high quality MP3 audio chip known as the "WT5001". Therefore, you should be able to get some additional features and functionality from this document. Plus you may find some extra useful info from the Seeedstudio wiki. I have re-used some code from the Arduino Boombox tutorial... you will find extra Grove Serial MP3 functions on that page.

I will warn you... the Grove Serial MP3 player can play WAV files, however for some reason it would not play many of the sound files in this format. Once the sounds were converted to the MP3 format, I did not look back. So if you decide to take on this project, make sure your sound files are in MP3 format, you'll have a much better outcome.

I decided to introduce a random sound selection for each drum pad to extend the novelty of this instrument, which meant that I had to come up with a fancy way to illuminate the LEDs. I demonstrated some of my other LED sequences on my instagram account. I sometimes use instagram to show my work in progress.

Have a look at the video below to see this project in action, and putting the Grove Serial MP3 player through it's paces.

The Video

First there was the Arduino Boombox, and now we have the Arduino Beatbox..... who knows what will come next !

Whenever I create a new project, I like to improve my Arduino knowledge. Sometimes it takes me into some rather complicated topics. There is a lot I do not know about Arduino, but I am enjoying the journey. I hope you are too !! Please Google plus one this post if it helped you in any way. These tutorials are free, which means I survive on feedback and plus ones... all you have to do is just scroll a little bit more and click that button :)

If you like this page, please do me a favour and show your appreciation :

Visit my ArduinoBasics Google + page.
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I can also be found on Pinterest and Instagram.
Have a look at my videos on my YouTube channel.

However, if you do not have a google profile...
Feel free to share this page with your friends in any way you see fit.

Arduino BeatBox

Create your very own Arduino BeatBox !

Home-made capacitive touch sensors are used to trigger the MP3 drum sounds stored on the Grove Serial MP3 player. I have used a number of tricks to get the most out of this module, and I was quite impressed on how well it did. Over 130 sounds were loaded onto the SDHC card. Most were drum sounds, but I added some farm animal noises to provide an extra element of surprise and entertainment. You can put any sounds you want on the module and play them back quickly. We'll put the Grove Serial MP3 module through it's paces and make it into a neat little BeatBox !!

Key learning objectives

How to make your own beatbox
How to make capacitive drum pad sensors without using resistors
How to speed up Arduino's Analog readings for better performance
How to generate random numbers on your Arduino

Parts Required:

Arduino UNO or compatible board
Grove Base Shield
Grove Serial MP3 Player
Grove Sliding Potentiometer
Grove Button or Grove Button (P)
Grove Universal 4 pin cables
Battery Holder
SanDisk 8GB Ultra Micro SDHC Memory card
Portable Powered Speaker or Headphones
4 LEDs - 1 x Green, 1 x Blue, 1 x Red and 1 x Yellow
A shoe box, paper, aluminum foil, scissors, glue etc. etc.

Making the drum pads

Fritzing Sketch

Grove Connections

Grove Connections (without base shield)

Arduino Sketch


/* =================================================================================================
      Project: Arduino Beatbox
       Author: Scott C
      Created: 9th April 2015
  Arduino IDE: 1.6.2
      Website: http://arduinobasics.blogspot.com/p/arduino-basics-projects-page.html
  Description: This project uses home made capacitive sensors to trigger over 130 MP3 sounds
               on the Grove Serial MP3 player. 
               
               The ADCTouch library is used to eliminate the resistors from the Capacitive sensing circuit. 
               The code used for capacitive sensing was adapted from the ADCTouch library example sketches. 
               You can find the ADCTouch library and relevant example code here:
               http://playground.arduino.cc/Code/ADCTouch
               
               "Advanced Arduino ADC" is used to improve the analogRead() speed, and enhance the
               drum pad or capacitive sensor response time. The Advanced Arduino ADC code 
               was adapted from this site:
               http://www.microsmart.co.za/technical/2014/03/01/advanced-arduino-adc/
               
               
=================================================================================================== */
  #include <ADCTouch.h>
  #include <SoftwareSerial.h>
  
  
  //Global variables
  //===================================================================================================
  int potPin = A4;                           //Grove Sliding potentiometer is connected to Analog Pin 4
  int potVal = 0;
  byte mp3Vol = 0;                           //Variable used to control the volume of the MP3 player
  byte oldVol = 0;
  
  int buttonPin = 5;                         //Grove Button is connected to Digital Pin 5
  int buttonStatus = 0;
  
  byte SongNum[4] = {0x01,0x02,0x03,0x04};  //The first 4 songs will be assigned to the drum pads upon initialisation
  byte numOfSongs = 130;                    //Total number of MP3 songs/sounds loaded onto the SDHC card
  
  long randNumber;                          //Variable used to hold the random number - used to randomise the sounds.
  
  int ledState[4];                          //Used to keep track of the status of all LEDs (on or off)
  int counter = 0;
  
  SoftwareSerial mp3(3, 4);                 // The Grove MP3 Player is connected to Arduino digital Pin 3 and 4 (Serial communication)
       
  int ref0, ref1, ref2, ref3;               //reference values to remove offset
  int threshold = 100;
      
  // Define the ADC prescalers
  const unsigned char PS_64 = (1 << ADPS2) | (1 << ADPS1);
  const unsigned char PS_128 = (1 << ADPS2) | (1 << ADPS1) | (1 << ADPS0);
  
  
  
  //Setup()
  //===================================================================================================
  void setup(){
    //Initialise the Grove MP3 Module
    delay(2500);                              //Allow the MP3 module to power up        
    mp3.begin(9600);                          //Begin Serial communication with the MP3 module
    setPlayMode(0x00);                        //0x00 = Single song - played once ie. not repeated.  (default)
    
    //Define the Grove Button as an INPUT
    pinMode(buttonPin, INPUT);
    
    //Define the 4 LED Pins as OUTPUTs
    pinMode(8, OUTPUT);                       //Green LED
    pinMode(9, OUTPUT);                       //Blue LED
    pinMode(10, OUTPUT);                      //Red LED
    pinMode(11, OUTPUT);                      //Yellow LED
    
    //Make sure each LED is OFF, and store the state of the LED into a variable.
    for(int i=8;i<12;i++){
      digitalWrite(i, LOW);
      ledState[i-8]=0;
    } 
    
    //Double our clock speed from 125 kHz to 250 kHz
    ADCSRA &= ~PS_128;   // set up the ADC
    ADCSRA |= PS_64;    // set our own prescaler to 64 
    
    //Create reference values to account for the capacitance of each pad.
    ref0 = ADCTouch.read(A0, 500);
    ref1 = ADCTouch.read(A1, 500);      //Take 500 readings
    ref2 = ADCTouch.read(A2, 500);
    ref3 = ADCTouch.read(A3, 500);
    
     //This helps to randomise the drum pads.
     randomSeed(analogRead(0));
  }
  
  
  
  // Loop()
  //===================================================================================================     
  void loop(){
     
    //Take a reading from the Grove Sliding Potentiometer, and set volume accordingly
    potVal = analogRead(potPin);
    mp3Vol = map(potVal, 0, 1023, 0,31);              // Convert the potentometer reading (0 - 1023) to fit within the MP3 player's Volume range (0 - 31)
    if((mp3Vol>(oldVol+1))|(mp3Vol<(oldVol-1))){      // Only make a change to the Volume on the Grove MP3 player when the potentiometer value changes
      oldVol = mp3Vol;
      setVolume(mp3Vol);
      delay(10);                                      // This delay is necessary with Serial communication to MP3 player
    }
    
    //Take a reading from the Pin attached to the Grove Button. If pressed, randomise the MP3 songs/sounds for each drum pad, and make the LEDs blink randomly.
    buttonStatus = digitalRead(buttonPin);
    if(buttonStatus==HIGH){
      SongNum[0]=randomSongChooser(1, 30);
      SongNum[1]=randomSongChooser(31, 60);
      SongNum[2]=randomSongChooser(61, 86);
      SongNum[3]=randomSongChooser(87, (int)numOfSongs);
      randomLEDBlink();
    }
    
    //Get the capacitive readings from each drum pad: 50 readings are taken from each pad. (default is 100) 
    int value0 = ADCTouch.read(A0,50);        //  Green drum pad
    int value1 = ADCTouch.read(A1,50);        //   Blue drum pad
    int value2 = ADCTouch.read(A2,50);        //    Red drum pad
    int value3 = ADCTouch.read(A3,50);        // Yellow drum pad
    
    //Remove the offset to account for the baseline capacitance of each pad.
    value0 -= ref0;       
    value1 -= ref1;
    value2 -= ref2;
    value3 -= ref3;
    
    
    //If any of the values exceed the designated threshold, then play the song/sound associated with that drum pad.
    //The associated LED will stay on for the whole time the drum pad is pressed, providing the value remains above the threshold. 
    //The LED will turn off when the pad is not being touched or pressed.
    if(value0>threshold){
      digitalWrite(8, HIGH);
      playSong(00,SongNum[0]);
    }else{
      digitalWrite(8,LOW);
    }
    
    if(value1>threshold){
      digitalWrite(9, HIGH);
      playSong(00,SongNum[1]);
    }else{
      digitalWrite(9,LOW);
    }
    
    if(value2>threshold){
      digitalWrite(10, HIGH);
      playSong(00,SongNum[2]);
    }else{
      digitalWrite(10,LOW);
    }
    
    if(value3>threshold){
      digitalWrite(11, HIGH);
      playSong(00,SongNum[3]);
    }else{
      digitalWrite(11,LOW);
    }
  }
      
   
  // writeToMP3: 
  // a generic function that simplifies each of the methods used to control the Grove MP3 Player
  //===================================================================================================
  void writeToMP3(byte MsgLEN, byte A, byte B, byte C, byte D, byte E, byte F){
    byte codeMsg[] = {MsgLEN, A,B,C,D,E,F};
    mp3.write(0x7E);                        //Start Code for every command = 0x7E
    for(byte i = 0; i<MsgLEN+1; i++){
      mp3.write(codeMsg[i]);                //Send the rest of the command to the GROVE MP3 player
    }
  }
  
  
  //setPlayMode: defines how each song is to be played
  //===================================================================================================
  void setPlayMode(byte playMode){
    /* playMode options:
          0x00 = Single song - played only once ie. not repeated.  (default)
          0x01 = Single song - cycled ie. repeats over and over.
          0x02 = All songs - cycled 
          0x03 = play songs randomly                                           */
    writeToMP3(0x03, 0xA9, playMode, 0x7E, 0x00, 0x00, 0x00);  
  }
  
  
  //playSong: tells the Grove MP3 player to play the song/sound, and also which song/sound to play
  //===================================================================================================
  void playSong(byte songHbyte, byte songLbyte){
    writeToMP3(0x04, 0xA0, songHbyte, songLbyte, 0x7E, 0x00, 0x00);            
    delay(100);
  }
  
  
  //setVolume: changes the Grove MP3 player's volume to the designated level (0 to 31)
  //===================================================================================================
  void setVolume(byte Volume){
    byte tempVol = constrain(Volume, 0, 31);             //Volume range = 00 (muted) to 31 (max volume)
    writeToMP3(0x03, 0xA7, tempVol, 0x7E, 0x00, 0x00, 0x00); 
  }
  
  
  //randomSongChooser: chooses a random song to play. The range of songs to choose from
  //is limited and defined by the startSong and endSong parameters.
  //===================================================================================================
  byte randomSongChooser(int startSong, int endSong){
    randNumber = random(startSong, endSong);
    return((byte) randNumber);
  }
  
  
  //randomLEDBlink: makes each LED blink randomly. The LEDs are attached to digital pins 8 to 12.
  //===================================================================================================
  void randomLEDBlink(){
   counter=8;
   for(int i=0; i<40; i++){
     int x = constrain((int)random(8,12),8,12);
     toggleLED(x);
     delay(random(50,100-i));
   }
     
    for(int i=8;i<12;i++){
      digitalWrite(i, HIGH);
    }
    delay(1000);
    for(int i=8;i<12;i++){
      digitalWrite(i, LOW);
      ledState[i-8]=0;
    }
  }
  
  
  //toggleLED: is used by the randomLEDBlink method to turn each LED on and off (randomly).
  //===================================================================================================
  void toggleLED(int pinNum){
    ledState[pinNum-8]= !ledState[pinNum-8];
    digitalWrite(pinNum, ledState[pinNum-8]);
  }

Arduino Code Discussion

You can see from the Arduino code above, that it uses the ADCTouch library. This library was chosen over the Capacitive Sensing Library to eliminate the need for a high value resistor which are commonly found in Capacitive Sensing projects).

To increase the speed of the Analog readings, I utilised one of the "Advanced Arduino ADC" techniques described by Guy van den Berg on this Microsmart website.

The readings are increased by modifying the Arduino's ADC clock speed from 125kHz to 250 kHz. I did notice an overall better response time with this modification. However, the Grove Serial MP3 player is limited by it's inability to play more than one song or sound at a time. This means that if you hit another drum pad while the current sound is playing, it will stop playing the current sound, and then play the selected sound. The speed at which it can perform this task was quite impressive. In fact it was much better than I thought it would be. But if you are looking for polyphonic playability, you will be dissapointed.

This Serial MP3 module makes use of a high quality MP3 audio chip known as the "WT5001". Therefore, you should be able to get some additional features and functionality from this document. Plus you may find some extra useful info from the Seeedstudio wiki. I have re-used some code from the Arduino Boombox tutorial... you will find extra Grove Serial MP3 functions on that page.

I will warn you... the Grove Serial MP3 player can play WAV files, however for some reason it would not play many of the sound files in this format. Once the sounds were converted to the MP3 format, I did not look back. So if you decide to take on this project, make sure your sound files are in MP3 format, you'll have a much better outcome.

I decided to introduce a random sound selection for each drum pad to extend the novelty of this instrument, which meant that I had to come up with a fancy way to illuminate the LEDs. I demonstrated some of my other LED sequences on my instagram account. I sometimes use instagram to show my work in progress.

Have a look at the video below to see this project in action, and putting the Grove Serial MP3 player through it's paces.

The Video

First there was the Arduino Boombox, and now we have the Arduino Beatbox..... who knows what will come next !

Whenever I create a new project, I like to improve my Arduino knowledge. Sometimes it takes me into some rather complicated topics. There is a lot I do not know about Arduino, but I am enjoying the journey. I hope you are too !! Please Google plus one this post if it helped you in any way. These tutorials are free, which means I survive on feedback and plus ones... all you have to do is just scroll a little bit more and click that button :)

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Project Review – Silicon Chip Capacitance Substitution Box

Introduction

Every month Australian electronics magazine Silicon Chip publishes a variety of projects, and in some cases various (well … one of two) electronics retailers will pick up the project and offer it as a kit. However for an increasing number of new projects they don’t, which leaves the interested reader with one option – build the entire project from scratch.

But thankfully this is no longer the case – as the team from Silicon Chip now offer a range of project PCBs and matching front panels for sale directly from their website. Although buying these parts is not the cheapest option, it gives the busy person who likes making things a quick start – or the inexperienced more opportunities to complete a successful project.

So as a test of this new service, I bought the PCB and front panel for the Capacitance Substitution Box project described by Nicholas Vinen in the Juily 2012 issue of SC:

This is something I’ve meant to make for a while – but didn’t really have the inclination to make one from scratch, so it was neat to see a version published in the magazine. I believe the subjects in the magazine article are oftern prototypes, which explains the difference in colour for the front panel.

The parts arrived in a week after placing the order, and are of a high quality:

When complete, the capacitance substitution box PCB and panel will fit nicely into an Altronics H0151 enclosure, so you don’t need to do any drilling or filing. The next task was to organise the required parts. The rotary switches, terminal posts and the usual odds and ends can be found at Altronics, Jaycar or other suppliers. However the main components – the capacitors – offered two options.

The first option is to simply use capacitors from personal stock or the stores. However the tolerance of these parts can vary wildly, with up to twenty percent either way. This is ok for simple uses, however when values are combined – the tolerance of larger values can negate the lower values completely. So instead I’ve chosen the second option – which involves using brand-name low-tolerance capacitors.

Thus I turned to element14 who stock not only a huge range of not only regular but also the low-tolerance capacitors, and can also have them on my desk usually by the next working day. Finally, it’s nice to have all the parts arrive in little bags… neatly organised ready to go:

It’s easy to search for low-tolerance parts with element14, as the automatic filtering has tolerance as a parameter:

Furthermore you can also ensure you have the voltage rating of at least 50V DC as well. So after half an hour the capacitor order was completed and arrived when expected – using parts from Panasonic, Vishay, and Wima. The tolerances of our capacitors used varied between one and ten percent, which will help improve the accuracy of the substitution box.

Assembly

The PCB has the capacitor values labelled neatly on the silk-screen, so soldering in all the capacitors was a relatively simple but long operation. Having them arrive in separate packets made life a lot easier. During the soldering process it’s a good idea to have a break or two, which helps you avoid fatigue and making any mistakes.

There may be a few capacitors that are a little too wide to fit with the others, so they can be mounted on the other side of the PCB:

However they all end up fitting well:

The next step was to configure the first rotary switch for six position use, then cut the plastic stopped from the side of each rotary switch. In the following image you have a before and after example:

Now the rotary switches can have their shafts trimmed and then be soldered onto the PCB:

However ensure you have the first rotary switch in the right way – that is the selections are selected across the top half, not the bottom. Remove the nuts from the rotary switches, and double-check all the capacitors are fitted, as once the next step is completed … going back will be difficult to say the least.

At this point the banana sockets can be fitted to the panel, and then soldered into place, and then you’re finished. Just place the panel/PCB combination inside the box and screw it down:

Using the Capacitance Substitution Box

Does it work? Yes – however you don’t get exact values, there will always be a tolerance due to the original tolerance of the capacitors used and the stray capacitance of the wires between the box and the circuit (or capacitance meter). Nevertheless our example was quite successful. You can see the box in action with our Altronics LC meter kit in this video.

Again, using the best tolerance capacitors you can afford will increase the accuracy of this project.

Conclusion

Over time this would be a useful piece of equipment to have – so if your experiments or projects require varying capacitor value, this project will serve the purpose nicely. Plus it helps with mental arithmetic and measures of capacitance! Please do not ask me for copies of the entire Silicon Chip article, refusal may offend. Instead – visit their website for a reprint or digital access.

And if you enjoyed this article, or want to introduce someone else to the interesting world of Arduino – check out my book (now in a third printing!) “Arduino Workshop”.

Have fun and keep checking into tronixstuff.com. Why not follow things on twitter, Google+, subscribe for email updates or RSS using the links on the right-hand column, or join our forum – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other – and we can all learn something.

The post Project Review – Silicon Chip Capacitance Substitution Box appeared first on tronixstuff.

Mobile chicken coop includes wireless sensors

In and of itself this mobile chicken coop is a pretty nice build. There are some additional features lurking inside which you don’t find on most coops. [Neuromancer2701] built-in a set of sensors which can be accessed wirelessly. It makes it a snap to check up on the comfort of the hens without leaving the couch.

At the heart of the sensor system is an Arduino along with an Xbee module. The build isn’t quite finished yet, but so far three sensors have been implemented. A thermistor is used to read the temperature inside the coop. To make sure there’s enough water, two sheets of foil tape were applied to the water reservoir. The CapSense library measures the capacitance between these plates which correlates to the water lever (we’ve seen this type of water level sensor before). And finally, there’s a sensor that can tell if the door to the coop is open or shut.

He’s having trouble automating the door itself. This can be pretty tricky, especially if you go for a super complicated locking mechanism like this one.

Filed under: home hacks

Hack a Day 28 Jan 18:01

arduino capacitance capacitive sensor capsense chicken chicken coop home hacks water sensor

Build a Touchless 3D Tracking Interface with Everyday Materials

Combine low-tech materials with some high-tech components and build a completely Touchless 3D Tracking Interface. Explore capacitive sensing by using several panels of cardboard lined with aluminum foil. These panels, when charged, create electric fields that correspond to X, Y, and Z axes to create a 3D cube. With the aid of an Arduino microcontroller and some supplied code, movements inside the cube are tracked as your hand moves around inside the field.

For Weekend Projects makers looking for an introduction to Arduino, this is a great project to learn from. Once you’ve gathered all your parts, this project should only take a couple hours to complete – you’ll be playing 3D Tic Tac Toe before the weekend is over!

Once your touchless 3D tracker is up and running, what you do with it is only limited by your own imagination! The original implementation of this project comes from media artist Kyle McDonald, who has suggested the following uses and applications:

Make an RGB or HSB color picker
Control video or music parameters; sequence a beat or melody
Large, slightly bent surface with multiple plates + a projector = “Minority Report” interface

Sign up below for the Weekend Projects Newsletter to receive the projects before anybody else does, get tips, see other makers’ builds, and more.

More:
See all of the Weekend Projects posts

Filed under: Arduino, MAKE Projects, Weekend Projects

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Arduino BeatBox

Key learning objectives

Parts Required:

Making the drum pads

Fritzing Sketch

Grove Connections

Grove Connections (without base shield)

Arduino Sketch

Arduino Code Discussion

The Video

Arduino BeatBox

Key learning objectives

Parts Required:

Making the drum pads

Fritzing Sketch

Grove Connections

Grove Connections (without base shield)

Arduino Sketch

Arduino Code Discussion

The Video

Project Review – Silicon Chip Capacitance Substitution Box

Mobile chicken coop includes wireless sensors

Build a Touchless 3D Tracking Interface with Everyday Materials