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Output Devices

Group assignments

  • measure the power consumption of an output device

My group assignments

Individual　Assignments

  • add an output device to a microcontroller board you've designed,and program it to do something

Have you answered these questions?

  • Linked to the group assignment page.
  • Documented how you determined power consumption of an output device with your group.
  • Documented what you learned from interfacing output device(s) to microcontroller and controlling the device(s).
  • Linked to the board you made in a previous assignment or documented your design and fabrication process if you made a new board.
  • Explained the programming process/es you used.
  • Explained any problems you encountered and how you fixed them.
  • Included original source code and any new design files.
  • Included a ‘hero shot’ of your board.

PC working environment

  • PC: MacBook Pro(16-inch,2019)
  • OS: Sonoma 14.7.2
  • Terminal: zsh

hero shot

I tried to display Hello, Fab Academy on the LCD display! alt text

hero video

organic electroluminescent display

What is organic electroluminescent display?

An OLED display (OLED display) is a display that uses the phenomenon of organic light emitted by electricity. Compared to LCD displays, OLED displays are thinner, lighter, have a faster response time, and offer better image quality.

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FEATURES

  • Resolution: 128 x 64 dot matrix panel
  • Power supply
    • VDD = 1.65V to 3.3V for IC logic
    • VCC=7Vto15V forPaneldriving
  • For matrix display
    • OLEDdrivingoutputvoltage,15Vmaximum
    • Segmentmaximumsourcecurrent:100uA
    • Commonmaximumsinkcurrent:15mA
    • 256stepcontrastbrightnesscurrentcontrol
  • Embedded 128 x 64 bit SRAM display buffer
  • Pin selectable MCU Interfaces:
    • 8-bit6800/8080-seriesparallelinterface
    • 3/4wireSerialPeripheralInterface
    • I2CInterface
  • Screen saving continuous scrolling function in both horizontal and vertical direction
  • RAM write synchronization signal
  • Programmable Frame Rate and Multiplexing Ratio
  • Row Re-mapping and Column Re-mapping
  • On-Chip Oscillator
  • Chip layout for COG & COF
  • Wide range of operating temperature: -40°C to 85°C

1.try organic electroluminescent display

1.0 Connection

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1.1 programming

I gave Chat GPT the following requirements and asked them to write it.

  • board:XIAO ESP32S3
  • OLED display:SSD1306
  • Environment:Aruduino IDE


What I used

  • IDE : Arduino IDE
  • libraries
    • Wire.h : Library for handling I2C communication
    • Adafruit_GFX.h : Library for screen drawing
    • Adafruit_SSD1306.h : Library for SSD1306 OLED display
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128  // OLED width
#define SCREEN_HEIGHT 64  // OLED height
#define OLED_RESET -1  // Reset pin (not used)
#define SCREEN_ADDRESS 0x3C  // I2C address

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

void setup() {
  Serial.begin(115200);  // Start serial communication
  delay(1000);  // Wait for stabilization

  Serial.println("ESP32-S3 OLED test started!");

  // I2C pin configuration (GPIO5: SDA, GPIO6: SCL)
  Wire.begin(5, 6);

  // OLED initialization
  if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println("SSD1306 initialization failed");
    for (;;);  // Infinite loop to stop the program
  }

  Serial.println("OLED initialization successful!");

  // Display text on the OLED screen
  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(10, 10);
  display.println("Hello,Fab Academy!");
  display.display();

  // Also display text on the serial monitor
  Serial.println("Hello, OLED!");  // Here the string is printed to the serial monitor
}

void loop() {
  // Nothing to do in the loop
}

This program connects ESP32-S3 and OLED display (SSD1306) via I2C communication and displays “Hello, Fab Academy!

Constant Definition
SCREEN_WIDTH, SCREEN_HEIGHT OLED resolution (128 x 64 pixels)
OLED_RESET Reset pin (-1 since not used in this case)
SCREEN_ADDRESS I2C address of SSD1306 (0x3C)

Create an instance of an OLED display.

  • Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
    • Create a display object and set it to communicate via I2C
setup() function
Serial.begin(115200); Start serial communication (baud rate 115200bps)
delay(1000); wait 1 second before initialization
Serial.println(“ESP32-S3 OLED test started!”); Display start message on serial monitor
wire.begin(5, 6); start I2C communication by specifying SDA(GPIO5) / SCL(GPIO6)
display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS); Initialize OLED display
  • If failed → Error message is displayed on the serial monitor and stops in an infinite loop
  • In case of success → “OLED initialization successful!” is output to serial monitor
Display text on screen
display.clearDisplay(); clear screen
display.setTextSize(2); set text size to 2x
display.setTextColor(SSD1306_WHITE); set text color to white
display.setCursor(10, 10); move the cursor to the (10,10) position
display.println(“Hello, Fab Academy!”); display “Hello, Fab Academy!
display.display(); display.display();
display.println(“Hello, OLED!”); display “Hello, OLED!” also on serial monitor
loop() function
loop(), the program does nothing after setup() completes because nothing is written inside the loop()

1.2 result

alt text

It was successfully displayed!

DFplayer mini

In this case, we used DFplayer mini.

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FEATURES

  • Sampling rates (kHz): 8/11.025/12/16/22.05/24/32/44.1/48
  • 24 -bit DAC output, support for dynamic range 90dB , SNR support 85dB
  • Fully supports FAT16 , FAT32 file system, maximum support 32G of the TF card, support 32G of U disk, 64M bytes NORFLASH
  • A variety of control modes, I/O control mode, serial mode, AD button control mode
  • advertising sound waiting function, the music can be suspended. when advertising is over in the music continue to play
  • audio data sorted by folder, supports up to 100 folders, every folder can hold up to 255 songs
  • 30 level adjustable volume, 6 -level EQ adjustable

2.try DFplayer mini

2.0 datasheet

Pinout

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Serial communication connect

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At this time, RX of DFplayer is connected to TX of the microcontroller and TX to RX.

2.1 Connection

alt text alt text

At this time, RX of DFplayer is connected to TX of the microcontroller and TX to RX.

2.2 Creating audio files

I used Mr. Read Aloud for this project. It is free and anyone can easily create mp3s. You can also change your favorite voice.

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2.3 Insert data into SD card

Filename : 0001.mp3 (4 digit number) Format : FAT32

I used Disk Utility to set up the format.

In my case, I created a file named 01 in the SD card and inserted the mp3 data into it.

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Once done, insert it into the SD card.

2.4 programming

At first I tried using sample sketch, but but eventually had it modified to chatGPT.

What I used

  • IDE : Arduino IDE
  • libraries
    • SoftwareSerial.h : Library for using software serial communication
    • DFRobotDFPlayerMini.h : Library to control DFPlayer Mini 
#include <SoftwareSerial.h>
#include <DFRobotDFPlayerMini.h>

SoftwareSerial mySoftwareSerial(44,43);  // RX=44, TX=43 (cross connection)
DFRobotDFPlayerMini myDFPlayer;

void setup() {
  mySoftwareSerial.begin(9600);  // Start communication with DFPlayer
  Serial.begin(115200);

  Serial.println("Attempting to communicate with DFPlayer Mini using while loop");

  delay(3000);

  // Keep trying to initialize DFPlayer until it responds
  while(!myDFPlayer.begin(mySoftwareSerial)){
    Serial.print("Not connected yet");
    delay(300);
  }

  Serial.println("DFPlayer Mini is successfully communicating via serial!");
  myDFPlayer.volume(30);  // Set volume (0-30)

}

void loop() {
  // Add any necessary repeating processes here
 myDFPlayer.play(0001);     // Play 0001.mp3
 delay(5000);   //This value is changed by the song
}

This code is for playing an MP3 file (0001.mp3) using the ESP32-S3 and DFPlayer Mini.

Creating SoftwareSerial and DFPlayer Mini Instances
SoftwareSerial mySoftwareSerial(44,43); GPIO44 (RX) → DFPlayer TX
GPIO43 (TX) → DFPlayer RX
DFRobotDFPlayerMini myDFPlayer; Object to control the DFPlayer Mini
setup() function
mySoftwareSerial.begin(9600); Start communication with DFPlayer Mini (9600bps fixed)
Serial.begin(115200); Serial communication for debugging (115200bps)
Serial.println(“Attempting to communicate with DFPlayer Mini using while loop”); Display initialization message
delay(3000); waiting for DFPlayer Mini to start up (3 seconds)
Serial.print(“Notify the DFPlayer Mini with DFPlayer Mini using while loop”); Display the initialization message
Serial.print(“Not connected yet”); Notify that the connection is not made
delay(300); retry every 0.3 seconds
Serial.println(“DFPlayer Mini is successfully communicating via serial!”); display success message
myDFPlayer.volume(30); set volume to maximum (30)
myDFPlayer.play(1); play 0001.mp3
loop() function
myDFPlayer.play(1); play 0001.mp3 every time
play(1) is executed for each loop, so the sound is played over and over again

Debug

Actually, this task took a lot of time...
At first, there was no sound at all. The cause was that the DFPlayer was broken.At this time, this DF player was emitting heat...
Details are summarized in the last section.

2.5 result

3.Dbag

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approach

  • First, suspecting his own elementary mistakes, he debugged the circuit, the circuit board he had created, and the hardware, including misconnections and solder defects.
  • Next, with the advice of the instructor and others, he reviewed the library and code.
  • Next, on a Windows PC, reformatted the SD card and saved the MP3s
  • Finally, I suspected the DF Player mini itself (the DF Player mini I purchased was also generating heat)


Here are some important points we noticed

important point

1. Is it DF Player mini made by DF Robot? (Hardware)

  • Third party DF players exist, but they seem to use different libraries (Asia review: information from instructor Rico).


2. Are the exact libraries installed? (IDE, necessary preparation)

  • As mentioned above, there are third-party products and libraries available, so make sure the library that matches the device is installed.


3.In Window, reformat the SD card and save the data.

  • When saving MP3 in a micro SD card on a Mac, it may stop sounding due to the inclusion of Mac-related invisible files. (Internet information)
  • So, I reformatted the SD card on my Windows PC.
  • Reference site


4. Serial communication timing is critical (source code, serial communication issues)

alt text

  • Reason: Depending on the production lot, there is a time lag between the DF player mini and the microcontroller after power-on, and the serial communication fails due to the time lag.
  • Countermeasure: Put a delay for a few seconds before the serial communication start instruction or use a while statement to loop the serial communication start instruction until the communication connection is started. It is easy to understand if a progress comment is displayed on the serial monitor so that the status can be grasped. (WestHarima founder information)


5. It is important to allow time for songs to play (source code, problems when power is turned on again)

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  • This is caused by ignoring the time required for song playback and moving on to the next instruction.
  • To ensure the time necessary for the song to be played, Delay is inserted immediately after the song playback instruction to ensure playback time. (HIROE experience)


6. Check hardware (hard, physical damage such as heat generation or short circuit).

This is a problem I encountered, but if the sound does not play despite debugging investigations such as broken wires, bad solder, bad contact, wrong wiring, etc. and 1 to 5 are definitely cleared, the hardware may be physically broken. When we used a working DF Player mini that belonged to the instructor, the sound played back as if all the hard work we had done up to this point was a lie.


Reference

In my case, I am using software serial instead of hardware serial, and I am writing code with GPIO pin numbers for the pins that I specify for serial communication. I have not investigated whether this affects the operation, but on the advice of a local instructor, I am writing code with GPIO pin numbers.

In my case

For reference, I present below a table summarizing the causes I have considered and their solutions.

Suspect Reasons for Doubt Alibi
My Microcontroller Board - I made it myself.
- Circuit mistake (resistor).
- Insufficient milling.		 - Tested with a multimeter, no issues in the circuit.
DFPlayer Mini - Koharu might have short-circuited it.
- It might be defective.
- The microcontroller is an ESP32-S3.		 - Tested with another working DFPlayer Mini using the same board and code.
- Tried with official code and procedures.
SD Card - Formatted using a Mac.
- The file storage format might be incorrect.
- Might have been inserted incorrectly or loosely.
- The SD card was not recognized.		 - Reformatted using Windows.
- Followed the file format used by others who successfully got it working.
Wiring Connections - I might have miswired it while assembling.
- The wire could have broken during handling.
- Wires might have been swapped or inserted incorrectly.
- Might have followed the wrong pin configuration.		 - Tested with a multimeter, no issues in the circuit.
Jumper Wire Contact Issues - The wire might be broken internally.
- Not fully inserted.
- Inserted but too loose to make a proper connection.		 - Tested with a multimeter, confirmed connection.
Code - There’s no definitive "correct" code, so it's unclear if it's right.
- Possible mistakes in declarations or libraries.
- The copied code might be from a different sample.		 - Used official code.
Soldering Issues - I soldered it myself.
- The multimeter check might not have been thorough.
- The correct amount of solder is unclear.
- Previously, a device didn’t work due to soldering issues.		 - Tested with a multimeter, no issues in the circuit.

data file

impressions

  • After all, debugging is hard work. It is necessary to check the factors one by one and find out what is wrong.
  • I thought it could be used for Final project if a larger display was used.