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Output devices

Missions of this week:
  • Add an output device to a microcontroller board you've designed, and program it to do something

In the group assignment, we'd tried to use a stepper motor as an output component and use ammeter to test the output consumption. In my final project, I want to show some word introduction to the players, so in the individual part, I want to try other output that can showing information.

LCD (1602 - I2C connection)​

LCD stands for Liquid Crystal Display, which is a simple and inexpensive way to display information. The model I used is 1602, which means it can display 16 font per row in X axis and 2 row in y-axis.

Connection​

As the LCD is connected in I2C, so I need to check the I2C pin from the datasheet first.

SDA is D4 pin and SCL is D5 pin, so now we can conncet them to the LCD.

warning
  • The Vcc pin of the LCD need to connect to 5V. If it connected to 3.3V, the font will be so light that almost can't be seen.

Programming​

The software I used is Arduino IDE and library I used is LiquidCrystal_I2C

Details

To program the LCD screen easily, we need to install a LCD library:

I. Click the library icon on the left bar
II. Search the LiquidCrystal_I2C in the search bar
III. Install the LiquidCrystal_I2C library by Frank de Brabander

After the library is intalled, there will be a new column LiquidCrystal_I2C in the example.

Let test the Hello world example:

#include <Wire.h> 
#include <LiquidCrystal_I2C.h>

// Set the LCD address to 0x27 for a 16 chars and 2 line display, sometime 0x27 might need to change as 0X3F
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup()
{
	lcd.begin(); 	// initialize the LCD
	lcd.backlight();
	lcd.print("Hello, world!");  //change other word to display other font
  delay(1000);
}

void loop()
{

}

Here is the test result:

note

  • Sometime no font is shown even if the program is correct. There might be the default brightness setting is too dark.
    Turn to the back of the LCD and tune the blue variable resistance with a screwdriver, which can adjust the brightness of the font.

  • If the font is still not show, the reason might be the address of some LCD might is 0x3F, not 0x27. Change the code LiquidCrystal_I2C lcd(0x27, 16, 2); to LiquidCrystal_I2C lcd(0x3F, 16, 2); will solve it.

OLED (SSD1306 0.96 in)​

The next component I try is OLED, the SSD1306 0.96 version. The size of the OLED is much smaller that the 1602 LCD, but the font can showed is much more, which is 128x64.

Tutorial reference: https://randomnerdtutorials.com/esp32-ssd1306-oled-display-arduino-ide/

Connection​

The connect method is I2C, basically same as the LCD screen

note

Vcc can be both 3.3V or 5V

Programming​

Like the LCD component, we also need to install some library, one is Adafruit GFX Library and one is Adafruit SSD1306, both by Adafruit

Basic example​

Details

We can test the ssd1306_128x64_i2c example in the Adafruit SSD1306 library:

Reference: https://github.com/adafruit/Adafruit_SSD1306/blob/master/examples/ssd1306_128x64_i2c/ssd1306_128x64_i2c.ino

note
  • After the program is uploaded, there are no error but my OLED show nothing. After change the #define SCREEN_ADDRESS 0x3D to #define SCREEN_ADDRESS 0x3C in line 35, it work. Seems the address of some OLED might be 0x3D and some is 0x3C.

The testing result:

Showing "Hello, world!"​

Details
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels

// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

void setup() {
  Serial.begin(115200);

  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { // Address 0x3D for 128x64
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  delay(2000);
  display.clearDisplay();

  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(0, 10);
  // Display static text
  display.println("Hello, world!");
  display.display(); 
}

void loop() {
  
}

The testing result:

Details

First we need to convert the picture to code. I convert the Fablab MSC logo to size 128x64 first:

Then import the image to online converter: https://diyusthad.com/image2cpp
The converter can help us to convert the image pixel to the code and used in the programming.
I. Import the image
II. Check the result III. Change the Code output format to Arduino code
IV. Click the Generate code button to start convert
V. Copy the code between the { and }
VI. Paste the code in the line 16 in the example below.

/*********
  Rui Santos
  Complete project details at https://randomnerdtutorials.com  
*********/

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

static const uint8_t image_data_Saraarray[1024] = {
 //paste the 0xXX array here. 

};
 
void setup() {
  Serial.begin(115200);
 
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  delay(2000); // Pause for 2 seconds
 
  // Clear the buffer.
  display.clearDisplay();
  
  // Draw bitmap on the screen
  display.drawBitmap(0, 0, image_data_Saraarray, 128, 64, 1);
  display.display();
}
 
void loop() {
  
}

For the Fablab MSC logo sample, the code is here:

0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0x80, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xfc, 0x02, 0x03, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xf0, 0x0f, 0x80, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xc0, 0x3f, 0xc0, 0x3f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0x80, 0x7f, 0xf0, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0x00, 0x7f, 0xfc, 0x07, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xfe, 0x00, 0x00, 0x7e, 0x03, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xfc, 0x00, 0x00, 0x1f, 0x81, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xf8, 0x78, 0x00, 0x0f, 0xe1, 0xfe, 0x00, 0x7e, 0x1f, 0xc0, 0x1f, 0x0f, 0xfe, 0x1f, 0xc0, 0x1f, 
0xf0, 0xfc, 0x00, 0x07, 0xf8, 0xff, 0x00, 0x7c, 0x0f, 0xc0, 0x07, 0x0f, 0xfc, 0x0f, 0xc0, 0x07, 
0xff, 0xfc, 0x00, 0x07, 0xfd, 0xff, 0x00, 0x7c, 0x0f, 0xc0, 0x07, 0x0f, 0xfc, 0x0f, 0xc0, 0x07, 
0xef, 0xfc, 0x00, 0x07, 0xff, 0xff, 0x1f, 0xf8, 0x0f, 0xc3, 0x87, 0x0f, 0xf8, 0x0f, 0xc3, 0x87, 
0xe7, 0xfe, 0x00, 0x07, 0xff, 0x3f, 0x1f, 0xf8, 0x07, 0xc3, 0xc7, 0x0f, 0xf8, 0x07, 0xc3, 0xc7, 
0xc7, 0xff, 0x00, 0x0f, 0xff, 0x3f, 0x1f, 0xf8, 0x87, 0xc3, 0x87, 0x0f, 0xf8, 0xc7, 0xc3, 0x87, 
0xc7, 0xff, 0x80, 0x1f, 0xff, 0x3f, 0x1f, 0xf0, 0xc3, 0xc3, 0x07, 0x0f, 0xf0, 0xc3, 0xc3, 0x07, 
0xc7, 0xff, 0xf0, 0xff, 0xff, 0x1f, 0x00, 0x70, 0xc3, 0xc0, 0x0f, 0x0f, 0xf0, 0xc3, 0xc0, 0x0f, 
0x87, 0xff, 0xff, 0xff, 0xff, 0x1f, 0x00, 0x61, 0xc3, 0xc0, 0x07, 0x0f, 0xf1, 0xc3, 0xc0, 0x07, 
0x87, 0xff, 0xff, 0xff, 0xff, 0x1f, 0x00, 0x61, 0xe1, 0xc0, 0x03, 0x0f, 0xe1, 0xe1, 0xc0, 0x03, 
0x87, 0xff, 0xff, 0xff, 0xfe, 0x1f, 0x1f, 0xe1, 0xe1, 0xc3, 0xc3, 0x0f, 0xe1, 0xe1, 0xc3, 0xe1, 
0x87, 0xc3, 0xff, 0xfe, 0x18, 0x1f, 0x1f, 0xc0, 0x01, 0xc3, 0xe1, 0x0f, 0xc0, 0x00, 0xc3, 0xe1, 
0x87, 0x80, 0xff, 0xf8, 0x00, 0x0f, 0x1f, 0xc0, 0x00, 0xc3, 0xe1, 0x0f, 0xc0, 0x00, 0xc3, 0xe1, 
0x87, 0x00, 0x7f, 0xf0, 0x00, 0x0f, 0x1f, 0xc0, 0x00, 0xc3, 0xc1, 0x0f, 0x80, 0x00, 0xc3, 0xc1, 
0x87, 0x00, 0x7f, 0xe0, 0x00, 0x1f, 0x1f, 0x87, 0xf8, 0x00, 0x03, 0x00, 0x07, 0xf8, 0x00, 0x03, 
0x87, 0x00, 0x3f, 0xe0, 0x00, 0x1e, 0x1f, 0x87, 0xf8, 0x00, 0x07, 0x00, 0x07, 0xf8, 0x00, 0x07, 
0x87, 0x00, 0x1f, 0xc0, 0x03, 0x1e, 0x1f, 0x0f, 0xf8, 0x00, 0x0f, 0x00, 0x0f, 0xfc, 0x00, 0x0f, 
0x87, 0x00, 0x1f, 0xc0, 0x07, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xc7, 0x80, 0x1f, 0xc0, 0x0f, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xc7, 0x80, 0x1f, 0x80, 0x0f, 0x1f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xc7, 0xc0, 0x1f, 0x80, 0x1f, 0x3f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xe7, 0xc0, 0x1f, 0xc0, 0x1f, 0x3f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xe7, 0xe0, 0x1f, 0xc0, 0x3f, 0x7f, 0xff, 0xfb, 0xfc, 0xfb, 0x9e, 0xff, 0x77, 0xdb, 0xff, 0xb7, 
0xf3, 0xe0, 0x3f, 0xc0, 0x7e, 0x7f, 0x27, 0x31, 0x98, 0x73, 0x00, 0x92, 0x07, 0x02, 0x60, 0x23, 
0xf0, 0xe0, 0x7f, 0xf3, 0xf8, 0xff, 0x26, 0x2f, 0x13, 0x33, 0x75, 0x91, 0xcf, 0x76, 0x2b, 0x6b, 
0xf8, 0x60, 0x7f, 0xff, 0xe0, 0xff, 0x06, 0xaf, 0x03, 0x38, 0x74, 0xa1, 0xc7, 0x72, 0x8b, 0x23, 
0xfc, 0x00, 0x7f, 0xff, 0xc1, 0xff, 0x50, 0x07, 0x0a, 0x7d, 0x21, 0xb6, 0xcf, 0x36, 0xcb, 0x63, 
0xfc, 0x00, 0x7f, 0xff, 0x03, 0xff, 0xfd, 0xd3, 0xec, 0xf3, 0x9c, 0xf7, 0x27, 0x93, 0xeb, 0x3b, 
0xfe, 0x00, 0x7f, 0xfc, 0x07, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0x80, 0x7f, 0xf0, 0x0f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xc0, 0x3f, 0xe0, 0x3f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xe0, 0x0f, 0x80, 0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xf8, 0x06, 0x01, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0x06, 0x0f, 0xff, 0xff, 0x00, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff

The testing result:

WS2812B​

WS2812B is playing a key role in the final project game, so here I use the WS2812B connecting to the new development board, make sure the new development board is compatible to WS2812B.

Connection​

The connect of WS2812B need a 5V, Din and GND. The Din pin is for the MCU to give signal, controlling the color of the WS2812B, and it can be any I/O pin. Here I use the D8 pin to connect to the Din pin. The Dout pin is used to connect to the next WS2812B if necessary.

Programming​

The library I used is Adafruit NeoPixel by Adafruit.

Basic example​

Details

Test the strandtest example in the Adafruit NeoPixel library:

Reference: https://github.com/adafruit/Adafruit_NeoPixel/blob/master/examples/strandtest/strandtest.ino

There are two place need to adjust in the sample code, as I connect the WS2812B to D8 pin, so the pin in line 20 should be changed to D8, and my testing WS2812B has 62 pixels, so the number in line 23 should be changed to 62.

#define LED_PIN   D8

// How many NeoPixels are attached to the Arduino?
#define LED_COUNT 62

The testing result: