Plan and sketch a potential final project

I have an idea of making a special accoustic guitar:

  • An accoustic Guitar looks like:
      • Basically i will use the CNC and laser cutter to make the accoustic room for the guitar I will 3D print the tunning knobs and kneck parts I will design a circuit that allows me to click on a button to start recording and playback on loop after i push the button again to stop recording. I will have to program the controller for the memory read and playback
    • I am curious to see if the playbackwill not interfere with the microphone to create an echo
    For copyrights and license, kindly refer to Invention and Intellectual property week documentation







    I am still figuring out what kind of circuit i will be using. but i will continously update as the weeks go by

    But in the end

    1. Final guitar looks like this
    3. The electronics inside is like this
    
     
    This page is a summary of the work done on the final project.
     
     
    A more detailed process is found on the Project requirements/presentation week page.
      Its link is Here.
     
    
     
    Welcome to the summary
    
     Mid work this is one note list of todos i had! Such a journey!
      Plan for dissemination of my project:
      1. finish the embedded system part by Monday the 29th of May
      2. Buy wood and cut the guitar by Saturday the 3rd June
      3. Assembly and testing by sunday the 4th June
      4. Make a video for final presentation before the 6th of June
      5. Document everything about my final project before the 7th of June.

      So far i have started working on the electronics part
      I also sent in the request for material from the fablab

     
      These are the shapes i cut on acrylic using a laser cutter to be able to visualize the project.
      
      
      
      Thinking about my Summary slides
      
      
      
    Questions to be answered
    
      What will it do?
      My proposed project is a guitar that has the capacity to record a priece of music and play it back on loop.
      The user of the guitar may choose to play another live piece of music. Then it will sound like two pieces of music are playing at the same time.
      
      Who's done what beforehand?
      In the fab academy, I saw people who did the boom box, another one who did “Legos” for Sound
      Physical Modular Sound Blocks for sound and music and many other projects.
      However none of them resembled mine exactly.
      On the market you may find guitar pedals with loops. However they are costly and it is a separate tool away from the guitar. MINE WILL BE INTEGRATED INSIDE A GUITAR.
      
      What will you design?
      1.	I will design the electronic circuit for the whole process of recording, writing on an SD card, playing back on a loop.
      2.	I will design the guitar frame: Acoustic version
      3.	Integrate everything together.
      
      What materials and components will be used?
      here is the list of material i will use:
          
        Not to mention the PLA that will be used in the printing of a case.

       Where will they come from?
      Most of these will be purchased by the fablab.
      If there is additional cost, i will cover.
      All items can be found on local market. I have links to the shops where i can find them.
      Items like hardwood boards will be procured by me going to the market place and picking them.
              
       How much will they cost?
      Items mentioned in the colored table have a cost estimation of around 220USD
      What parts and systems will be made?
      As i mentioned:
      The electornic part and,
      the guitar frame
                    
      What processes will be used?
      For the electronic part, I will program the SP32 to do tasks then connect the microphone and the speaker with its amplifier.
      For the frame i will use the ShopBot to cut parts that i can.
      Originally i had thought to make a mold and cast the tuning knobs but I was unable to find the right material for that.
      Therefore i will buy the ready-made knobs, the strings and other things i will not be able to print.
      Then i will assemble and test.

      What questions need to be answered?
      1. How to record sound/music and write it on an SD card?
      2. How to immediately playback sound/ music?
      3. Can the system be attached together?
      4. Can the sound come out of the case?

      How will it be evaluated?
      My project should be evaluated on following criteria:
      1. Is the sound coming out the one we recorded?
      2. Does the system look like a guitar?
      3. was it made by using computer controlled machines?   
      
      
      Also to have an idea of what will be done on the guitar frame
      

      
    CNC
    
      the guitar frame can be made using a DXF file  to make the case on plywood with 3mm thickness
      I started with cardboard to avoid wasting Material.
      
      
      I stacked a number of similar parts on each other to have the shape
      

      After all this is the frame i worked with
      

      
    Electronics
    
      As mentioned in the project development week,
      it was too complicated for me to write music (audio) on an HC SD card using just SP32
      

      I opted on using ISD1820 voice Module which records and plays back an audio input, then use the ESP32 to control a boutton like this:
      Longpress: Start recording mode
         Simplepress: playback the recorded music in loop indefinetely
      
      I had to find a PCB board to house all my main components
      
      
      
      

      Using Roland Miller was bringing a lots of problem since the screw that holds the tool was not tightening and the bed seemed not well leveled, I opted to mill the PCB using a CNC 
      A blue elephant ELECNC6090 Chinese model.
      Steps i took:
        1. convert the exported svg of traces into a png file. I used inkscape and kept the ratio of 1:1 always
        2. I used the Aspire CAM to create a pocket toolpath to clear the copper out and leave the traces alone.
        3. I editted the tool diameter, the feedrate and plunge rate to match the board details. 0.16mm pocket depth to remove copper and 1.8mm to cut out the contour.
      Bad results from Rml
      

      clean traces of CNC
      

      I felt happy of the outcome, considering the night i had spent trying the other machine that wouldn't work properly.
      
      Please note that i recognize the health risks associated with milling PCB with this type of CNC. If someone else has to do this, let them consider using serious PPE for their breathing

      then SOLDERED components on
      

      Uploaded in the  control program
      static const int buttonPin = 4;                  // switch pin
      static const int Feedback_Pin = 18;                  // Feedback pin from ISD1820
      int buttonStatePrevious = 1;                    // previousstate of the switch
      unsigned long minButtonLongPressDuration = 600;  // Time we wait before we see the press as a long press
      unsigned long buttonLongPressMillis;              // Time in ms when we the button was pressed
      bool buttonStateLongPress = false;                // True if it is a long press
      const int intervalButton = 50;                    // Time between two readings of the button state
      unsigned long previousButtonMillis;               // Timestamp of the latest reading
      unsigned long buttonPressDuration;                // Time the button is pressed in ms
      unsigned long currentMillis;                      // Variabele to store the number of milleseconds since the Arduino has started
      unsigned long startRectime;
      unsigned long EndRectime;
      bool playE = false;
      bool reco = false;
      const int rec = 16;
      const int play = 17;
      int timer_del = 0;
      int timerDel2 = 0;
      int recState = 0;
      int playState = 0;
      
      int LED_INDICATOR = 5;
      void setup() {
        Serial.begin(115200);                 
        pinMode(buttonPin, INPUT_PULLUP);  
        pinMode(rec, OUTPUT);
        pinMode(play, OUTPUT);
        pinMode(LED_INDICATOR,OUTPUT);
        pinMode(Feedback_Pin, INPUT);
        digitalWrite(rec, 0);
        digitalWrite(play, playState);
          
         }
      
      // Function for reading the button state
      void readButtonState() {
        if (currentMillis - previousButtonMillis > intervalButton) {
          int buttonState = digitalRead(buttonPin);
          if (buttonState == 0 && buttonStatePrevious == 1 && !buttonStateLongPress) {
            buttonLongPressMillis = currentMillis;
            buttonStatePrevious = 0;
            Serial.println("Button pressed");
          }
          buttonPressDuration = currentMillis - buttonLongPressMillis;
      
          if (buttonState == 0 && !buttonStateLongPress && buttonPressDuration >= minButtonLongPressDuration) {
            buttonStateLongPress = true;
            buttonStatePrevious = 0;
            Serial.println("Button long pressed");
            getting_ready_for_record();
            
            reco = true;
          }
          if (buttonState == 1 && buttonStatePrevious == 0) {
            buttonStatePrevious = 1;
            buttonStateLongPress = false;
            digitalWrite(LED_INDICATOR, HIGH);
          delay(500);
          digitalWrite(LED_INDICATOR, LOW);
          delay(500);
            Serial.println("Button released");
      
            if (buttonPressDuration < minButtonLongPressDuration) {
              Serial.println("Button pressed shortly");
              playE = true;
            }
          }
          previousButtonMillis = currentMillis;
        }
      }
      
      void loop() {
        currentMillis = millis();  // store the current time
        readButtonState();         // read the button state
         digitalWrite(play, playState);
      
      //if a single press occurs, playback starts looping
        if (playE) {
          playBack();
            }
      
      //if long pressed the button, record will start
        if (reco) { 
          digitalWrite(LED_INDICATOR, HIGH); 
          record();
          reco = false;
        }
      }
      
      //recording function ---recording time may vary from 1 upto 20 seconds
      void record() {
        Serial.println("Recording");
      
        long startTime = millis()/1000;
        long duration = 20; //up to 20sec
      
        while (millis()/1000 < startTime + duration) {
          digitalWrite(rec, 1);
        }
        digitalWrite(rec, 0);
      
      }
      
      //playback function 
      void playBack() {
        playState=1;
        digitalWrite(play, playState);
        int timer_delay=timer_del;
        while(timer_delay>0){
          playState = 0;
          timer_delay=timer_delay-1;
          digitalWrite(play, playState);
          }
      }  
      //  
      //  if (playState == 1) {
      //    Serial.println("Playing");
      //    if (millis() / 1000 - timer_del >= 1) {
      //      playState = 0;
      //      timer_del = timer_del+(millis() / 1000);
      //    }
      //  } else {
      //    if (millis() / 1000 - timer_del >= 0.1) {
      //      playState = 1;
      //      timer_del = timer_del+(millis() / 1000);
      //    }
      //  }
      //}
      void getting_ready_for_record(){
        int timer=1;
        while(timer<=5){
          digitalWrite(LED_INDICATOR, HIGH);
          delay(500);
          digitalWrite(LED_INDICATOR, LOW);
          delay(500);
          timer=timer+1;
          
        }
        startRectime=millis();
        attachInterrupt(digitalPinToInterrupt(Feedback_Pin),recordingstate,RISING);  //  function for creating external interrupts at pin2 on Rising (LOW to HIGH vice versa)
          
      }
      void recordingstate(){
        digitalWrite(LED_INDICATOR, LOW);
        detachInterrupt(Feedback_Pin);
        reco = false;
        EndRectime=millis();
        timer_del= (EndRectime-startRectime)/1000;
        Serial.println("Recording ended with period of "+String(timer_del)+"sec");
      }
    
      
    3D DESIGN AND PRINTING
    
    I designed the box in which the components will go
    
    
    The box printing
    

    The components fit in well
    

    Put the components inside the guitar and masked a bit for painting
    
    Now the guitar works:
    
    back
    
    front

    Again for more details 
    
    A more detailed process is found on the Project requirements/presentation week page.
      Its link is Here.
     
    

    
    thanks fabacademy!