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Week_9
Topic: Capacitive Touch Sensor



https://tungsten-waterfall-ae7.notion.site/Capative-Touch-Sensor-1433d345d4aa8038aa02f2ac8befc9ce



Week_8
Topic: Multiple Serial Data using Punctuation 

When you have to send multiple data items, you need a way to separate them.


If you’re sending them as ASCII-encoded strings, it’s simple: you can just put non-numeric punctuation bytes between them (like a comma or a space)
and
unique termination punctuation at the end (like a newline and/or carriage return).


carriage return (\r, ASCII 13)
newline (\n, ASCII 10)





Receiving the data in P5.js

  • Read the incoming serial data into a string until a carriage return and newline appear
  • split the string into substrings on the commas
  • convert the substrings into numbers
  • assign the numbers to variables to change your programNow that you’ve got a plan, put it into action.


-> Set up, take a look at week 7.


Change the serialEvent() function to read the incoming serial data as a string until it encounters a carriage return and newline (“\r\n”).




Use the split() function to split it in to an array of strings.




Creating Circle with P5 Serial:

 


Question:
How can I reduce the noise value to make it more stable?
Should I revise the code? or circuit?


Flow Control: Call and Response (Handshaking)

flow control:
The simplest way do to this is using a call-and-response method, where the sending program only sends when it’s told to do so.







No Line Ending:
the data that you send to the Serial Monitor is not followed by any special characters like newline (\n) or carriage return (\r).

New line:

When you choose New Line, the data sent from the Arduino will be followed by a newline character (\n).
This means that after each message is printed, the cursor moves to the next line in the Serial Monitor. It's like pressing Enter after printing the data, which helps in organizing the output into separate lines.



Joystick:




Week_7-2

Serial Output From p5.js Using the p5.webserial Library


function mouseDragged() {
  // map the mouseY to a range from 0 to 255:
  outByte = byte(map(mouseY, 0, height, 0, 255));

  // send it out the serial port:
  serial.write(outByte);
}



or
Key interaction:

function keyPressed() {
  if (key >= 0 && key <= 9) { // if the user presses 0 through 9
    outByte = (key * 25); // map the key to a range from 0 to 225
    serial.write(outByte); // send it out the serial port
  }
}


 if you want to convert multi-byte number strings to numeric values, you’ll need a new function to read ASCII encoded numeric strings called
parseInt().



if (key === "H" || key === "L") {
    // if the user presses H or L
    serial.write(key); // send it out the serial port
  }

If you tried to change the LED with the mouse, you didn’t see anything happen unless your output value was 72 or 76. Why is that?

Because of ASCII code. To solve this proble, we need to encode it.





Week_7

Connecting via the POSIX Command Line
- On MacOS, open the Terminal app, then get a list of your serial ports by typing

ls -1 /dev/cu.*



the Arduino is the one labeled usbmodemXXXX.

Then, Type:
cat /dev/cu.usbmodemXXXX.

It will show what the Arduino is sending out.


to stop showing the data :
Control + C

Also, it will allow you to read and write both together, having a separated screen :
screen /dev/cu.usbmodemXXXX 



three things the two computers need to agree upon:
  • Electrical: what is the voltage of the pulses?
  • Data rate: How often is a bit of data sent?
  • Logic: Does low voltage  mean the bit is a 0 or a 1?

three connections between the two computers:
  • a transmit line from sender to receiver
  • a receive line from receiver to sender
  • a common ground line




Send the data in many formats



call-and-response
 the sending program only sends when it’s told to do so, and the receiving program has to request new data every time it finishes reading what it’s got.

while (Serial.available() <= 0) {
    Serial.println("hello"); // send a starting message
    delay(300);              // wait 1/3 second
  }

means :
the loop will continue to run as long as there is no data available.


void loop() {
  if (Serial.available()) {Code }

Once you enter some output in “Serial Monitor_Message input” will go through the loop.



The P5.js WebSerial Library

To communicate with your microcontroller serially, you’re going to use the P5.js WebSerial library.

add this line:


you need to know if WebSerial is supported in the browser you’re using.




JavaScript, the language on which p5.js is based, relies heavily on events and callback functions. 

event is generated by the operating system when something significant happens.

callback function to respond to that event.


Event in p5:
  • noport – when there is no selected serial port
  • portavailable – when a serial port becomes available
  • data – new data arrives in a serial port
  • close – the serial port is closed
  • requesterror – something goes wrong when you request a serial port.


const serial = new p5.WebSerial();
let portButton;
let inData;
let outByte =0;

in Setup():

// if serial is available, add connect/disconnect listeners:
  navigator.serial.addEventListener("connect", portConnect);
  navigator.serial.addEventListener("disconnect", portDisconnect);

  // check for any ports that are available:
  serial.getPorts();

  // if there's no port chosen, choose one:
  serial.on("noport", makePortButton);

  // open whatever port is available:
  serial.on("portavailable", openPort);

  // handle serial errors:
  serial.on("requesterror", portError);

  // handle any incoming serial data:
  serial.on("data", serialEvent);
  serial.on("close", makePortButton);



After draw() : 


// if there's no port selected, 
// make a port select button appear:
function makePortButton() {

  // create and position a port chooser button:
  portButton = createButton("choose port");
  portButton.position(10, 10);

  // give the port button a mousepressed handler:
  portButton.mousePressed(choosePort);
}


// make the port selector window appear:
function choosePort() {
  if (portButton) portButton.show();
  serial.requestPort();
}


// open the selected port, and make the port 
// button invisible:
function openPort() {



  // wait for the serial.open promise to return,
  // then call the initiateSerial function
  serial.open().then(initiateSerial);



  // once the port opens, let the user know:
  function initiateSerial() {
    console.log("port open");
  }


  // hide the port button once a port is chosen:
  if (portButton) portButton.hide();
}



// pop up an alert if there's a port error:
function portError(err) {
  alert("Serial port error: " + err);
}

// read any incoming data as a string
// (assumes a newline at the end of it):
function serialEvent() {
  inData = Number(serial.read());
  console.log(inData);
}



// try to connect if a new serial port 
// gets added (i.e. plugged in via USB):
function portConnect() {
  console.log("port connected");
  serial.getPorts();
}


// if a port is disconnected:
function portDisconnect() {
  serial.close();
  console.log("port disconnected");
}


function closePort() {
  serial.close();
}

In p5.webserial, 9600 bits per second is the default, so you don’t have to set the rate if you want 9600bps. But if you want to set the rate to another value, change your serial.open() call in the openPort() function as follows:

let options = { baudrate: 9600};
serial.open(portName, options);

inData = variable for the data from Serial.

in draw():
text("sensor value: " + inData, 30, 50);




Draw a Graph With the Sensor Values







 but what if you want a larger range of numbers?  What if you want the full 0 to 1023 that analogRead() can output instead of just 0 to 255?

Write ‘Serial.println(variable)’;  instead of ‘Serial.write(variable);

then,
Now it will print the potentiometer’s value as an ASCII-encoded numeric string.

Once you’ve uploaded this to your Arduino, run your P5 sketch again.
Try adding

println(inData);
  at the end of your ‘Serial.event():


function serialEvent() {
  // read a string from the serial port:
  let inString = serial.readLine();

  // check to see that there's actually a string there:
  if (inString) {

  // convert it to a number:
  inData = Number(inString);
  }
}


Conclusion:




Week_4

Connect a Motor and Power Supply


Be sure to add the diode to your circuit correctly. The silver band on the diode denotes the cathode.
** if it’s added to your circuit incurrectly, it is keep flowing...turning on...
QQQQ: What? why? what? why?

When I didn’t even use the diode, it still worked with arduino code.
But when it was only added to the circuit incurrectly, the motor kept spinging without being controlled by the arduino.
QQQQ: Why?




Transistor(NPN) - 
Base <- digital Out
Diode <- Collector <- other side of motor
Emitor <- to ground

-> ** if it’s added to your circuit incurrectly, it is keep flowing...turning on...
QQQQ: What? why? what? why?


Using Motor Driver




- When pushing the switch, it switched the direction of the motor.

** BUT! the speed of the motor was a little bit aggresive to me, So I wanted to give the speed control with Potentiometer.
I went back to the first Lab, and took it as reference.


Experiment_01



- when you pressed the button, it becomes where to decide the direction of motor.
- no matter which point of potentiometer is, once you press the switch, based on the moment, the direction of the motor spin left if you turn the potentiometer to the left, and right if you turn the potentiometer to the right.

QQQQQ: WHY?


Experiment_02

- I asked Chat GPT, what was the problem, and I noticed that giving analogOutput to  the PWM can control the speed of the motor....

And solved the problem!

Here is the code. 


Here is How it turned out!









Week_2
Before starting the week2 Lab, I tried something experimential:
when you push one switch, the motor turns one direction. when the other switch is pressed, it turns the other direction.

Here is the plan:





1. it works.
2. However, the volage was extreamly decreased.

Q: How can I solve this problem?


Microcontroller

Lab: Digital Input and Output with an Arduino


1. connected Switch to Digital Input and order Arduino to read it. The monitor showed ‘0’ when it was not pressed, and ‘1’ when it was pressed.

2. To see what’s different between Digital Input and Analog Input, I also connected Switch to Analog Input, then the monitor showed ‘0’ when it was not pressed, but ‘1023’ when it was pressed. I assume that it showed 1023 because it was closed without any resistance. So I put the Resistor between Switch and Input, then it showed a different value. **Proved**



1. When the switch is not pressed, Yellow LED turns on, and when it is pressed, the Red LED lights on.
** For LED 220 ohm is good enough resistance. **




2. I also tried some exploration, editing the code. When the switch is pressed, the lights alternatively light on. and When it’s not pressed, it turns off.



1. I also tried the speaker to make sounds. When the switch is pressed, the it makes sounds and LED lighting on.

2. When I tried the code first, it didn’t make any sound. So I tried adding delay, then it worked.

Q: What is the relationship between ‘Tone’ and ‘Delay’?



1. Using Potentiometer and Analog Input, I controlled LED lights. works well.



2. Used two force sensing resistors to detect the signal. Connected the LEDs and used the signal to turn on the lights.

But here is the problem:




Q: when I mapped the input 400-900 to 0-255. it showed negative number when I didn’t interact with the sensor. But the LED was still lighting on even in negative signal. Why does it happen?

So I mapped it again 0-1023 to 0-255. then it worked as I expected.






Added Voltage as well.

Lab : Sensor change detection



int lastButtonState = LOW;   // state of the button last time you checked
int buttonPresses = 0;       // count of button presses

if (buttonState == HIGH) {
     buttonPresses++;
     Serial.print("Button has been pressed ");
     Serial.print(buttonPresses);
     Serial.println(" times.");
   }

int lastSensorState = LOW;   // sensor's previous state
// other globals and the setup go here

void loop() {
  // read the sensor:
  int sensorState = digitalRead(2);

  // if it's changed:
  if (sensorState != lastSensorState) {
    // take action or run a more detailed check
  }
  // save sensor state for next comparison:
  lastSensorState = sensorState;
}

Long Press / Short Press



When you press short amount of times, it says ‘short press’. < 250 ms
When you press long amount of times, it says ‘long press’. > 750 ms
When you hit it, it says ‘tab’.


Analog Sensor Threshold Detection

if you want the action be triggered only once when your sensor passes the threshold, you need to keep track of both its current state and previous state.



int lastSensorState = LOW;   // sensor's previous state
int threshold = 512;   // an arbitrary threshold value

void setup() {
  Serial.begin(9600);
}


void loop() {
  // read the sensor:
  int sensorState = analogRead(A0);

  // if it's above the threshold:
  if (sensorState >= threshold) {

    // check that the previous value was below the threshold:
     if (lastSensorState < threshold) {

        // the sensor just crossed the threshold
        Serial.println("Sensor crossed the threshold");
     }
  }

  // save button state for next comparison:
  lastSensorState = sensorState;
}



The key to detecting state change is the use of a variable to save the current state for comparison the next time through the loop.

lastButtonState = buttonState;

Detecting a Peak

int peakValue = 0;
int threshold = 50;  

void setup() {
  Serial.begin(9600);
}

void loop() {
  int sensorValue = analogRead(A0);
 if (sensorValue > peakValue) {
peakValue = sensorValue;
}

  if (sensorValue <= threshold) {
if (peakValue > threshold) {
Serial.println(peakValue);
peakValue = 0;
    }
  }
}



** Practice the coding again and again till getting used to it! **



Week_3

Tone Output


Activity_01
- Creating a tone buzzing with the code.
- Some error happened when I was mapping the range of sensor.
- 0-600 works, 10-600 didn’t work...
** Realized that when you put higher ‘From Low’, you also should put proper ratio of ‘To High’ range as well.
e.g) 0-600 -> 50 - 1000 ... then it worked.




Activiy_02
- Also set up the transistor to amplify the volume. but didn’t quite work.

Q: What is the specific function of Transistor? I didn’t quite understand...




Activity_03
** A Musical Instrument

- Once I sent the code to the program, it wans’t properly working. all the sensor made same tone.
** What I tried after that was to add ‘Delay’. Then it worked properly.


Activity_04
** Servo Motor



Q: How can I controll the speed of the motor?




Week_01
Arduino Nano Label


*VIN = Voltage Input
*A0-7 = Analog Pin
*D2-12 = Digital Pin




The goal is to understand how the electronicity works and Arduino kit through activities.
Started with the Arduino kit and multimeter.





1. Setting the Arduino Nano on Breadboard and checking it if the electronicity flows properly.
- I tried powering with 3.3v first. However, it wasn’t enough power to turn on more than 2 LED. So I switched it to 5v power.
- the pin supplying 5v was the bottom left one. So I connected it as main power.




2. Connected 5v Regulator -> switch button -> Resistor -> LED (Left)
3. Connected 5v Regulator -> switch button -> resistor -> LED -> LED 2 (center)
4. Connected 5v regulator -> switch button -> LED 1 - LED 2 (parallel connection) (right)

** We experienced that if you connect power to Regulator in reverse (input Ground), it generates A LOT of heats. **
** We experienced that if you use bigger Ohms resistor than enough, LED doesn’t turn on. **

** For some reason, parallel connection had brighter LED than series connection. **




5. Used Potentiometer.
- 5v regulator -> Potentiometer -> LED

** it showed that if you use one of sides of potentiometer as Input and center as Ground, you can control the resistance.
And, when you use the other side of the potentiometer as Input, the direction of ranges is reversed. **




6. (Left) connected multiple switches. With in the parallel connection, the LED lighted on when any button was pressed.
(Right) conncted multiple switches as well. With in the series connection, the LED lighted on when all the button were pressed all together.





7. added motor onto the board. When the switch was pressed, the LED lighed on, and motor was working.

** With this activity, I learned that each side of the switch has the both polarity, and we can utilize it to make multiple components work together.

** Also We noticed that if the motor's cables are reversed, the motor rotates in the other direction.