Hi there,
and Welcome here…
So here is an Example ,Demo I posted a while back, at the end you’ll see the actual unit working. The code is posted below, I found how you power the DS18B20 can also effect the overall operation, it supports both Parasitic power and traditional methods.
/**************************************************************************
This is an example of the Cheepest OLEDs based on SSD1306 & a DS18B20 Temp sensor.
connected to a grove Expansion Board.
This example is for a 128x32 pixel display using I2C to communicate
3 pins are required to interface (two I2C and one reset).
/**************************************************************************/
#include <Arduino.h>
//#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
//#include <OneWire.h>
//#include <DallasTemperature.h>
//#include <Fonts/FreeSerif12pt7b.h>
//#include <Fonts/FreeSerif9pt7b.h>
//#define ONE_WIRE_BUS D7
//OneWire oneWire(ONE_WIRE_BUS);
//DallasTemperature DS18B20(&oneWire);
//Adafruit_SSD1306 display(128, 64, &Wire, -1);
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 32 // OLED display height, in pixels
// Define monochrome graphics:
static const unsigned char PROGMEM _error [] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0x3F, 0xFC, 0x00, 0x00, 0xE0, 0x07, 0x00, 0x01, 0x80, 0x01, 0x80,
0x06, 0x00, 0x00, 0x60, 0x0C, 0x00, 0x00, 0x30, 0x08, 0x01, 0x80, 0x10, 0x10, 0x03, 0xC0, 0x08,
0x30, 0x02, 0x40, 0x0C, 0x20, 0x02, 0x40, 0x04, 0x60, 0x02, 0x40, 0x06, 0x40, 0x02, 0x40, 0x02,
0x40, 0x02, 0x40, 0x02, 0x40, 0x02, 0x40, 0x02, 0x40, 0x02, 0x40, 0x02, 0x40, 0x02, 0x40, 0x02,
0x40, 0x02, 0x40, 0x02, 0x40, 0x02, 0x40, 0x02, 0x40, 0x03, 0xC0, 0x02, 0x40, 0x01, 0x80, 0x02,
0x40, 0x00, 0x00, 0x02, 0x60, 0x00, 0x00, 0x06, 0x20, 0x01, 0x80, 0x04, 0x30, 0x03, 0xC0, 0x0C,
0x10, 0x03, 0xC0, 0x08, 0x08, 0x01, 0x80, 0x10, 0x0C, 0x00, 0x00, 0x30, 0x06, 0x00, 0x00, 0x60,
0x01, 0x80, 0x01, 0x80, 0x00, 0xE0, 0x07, 0x00, 0x00, 0x3F, 0xFC, 0x00, 0x00, 0x00, 0x00, 0x00
};
// Define the data holders:
//float t = m_temperature;
//float temps, m_temperature;
int class_number = 0;
long timer;
uint16_t error;
char errorMessage[256];
// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET -1 // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C //datasheet; 0x3D for 128x64, 0x3C for 128x32 Check the address with an I2C scanner. If it shows 0x78 (0x3C in 7-bit form)GOOD!
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
#define NUMFLAKES 10 // Number of snowflakes in the animation example
#define LOGO_HEIGHT 12
#define LOGO_WIDTH 12
static const unsigned char PROGMEM logo_bmp[] =
{ 0b00000000, 0b11000000,
0b00000001, 0b11000000,
0b00000001, 0b11000000,
0b00000011, 0b11100000,
0b11110011, 0b11100000,
0b11111110, 0b11111000,
0b01111110, 0b11111111,
0b00110011, 0b10011111,
0b00011111, 0b11111100,
0b00001101, 0b01110000,
0b00011011, 0b10100000,
0b00111111, 0b11100000,
0b00111111, 0b11110000,
0b01111100, 0b11110000,
0b01110000, 0b01110000,
0b00000000, 0b00110000 };
bool first10LoopCompleted = false;
int deviceCount = 0; // variable to store the number of devices connected
//DeviceAddress deviceAddress; // variable to store the device address
void setup() {
Wire.begin(9,10); //Check the address with an I2C scanner. If it shows 0x78 (or possibly 0x3C in 7-bit form), you’re good.
delay(250);
Serial.begin(9600);
delay(2000);
Serial.println();
Serial.println("Program " __FILE__ " compiled on " __DATE__ " at " __TIME__);
Serial.println();
Serial.println("Processor came out of reset.");
Serial.println();
delay (500);
// SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
Serial.println(F("SSD1306 allocation failed"));
//for(;;); // Don't proceed, loop forever
}
display.display();
delay(2000); // Pause for 2 seconds
// Clear the buffer
display.clearDisplay();
// Draw a single pixel in white
display.drawPixel(10, 10, SSD1306_WHITE);
// Show the display buffer on the screen. You MUST call display() after
// drawing commands to make them visible on screen!
display.display();
delay(1000);
//testdrawchar(); // Draw characters of the default font
//testdrawstyles(); // Draw 'stylized' characters
testscrolltext(); // Draw scrolling text
testdrawbitmap(); // Draw a small bitmap image
// Invert and restore display, pausing in-between
display.invertDisplay(true);
delay(500);
display.invertDisplay(false);
delay(500);
//testanimate(logo_bmp, LOGO_WIDTH, LOGO_HEIGHT); // Animate bitmaps
}
void loop() {
testscrolltext(); // Draw scrolling text
delay (5000);
}
void testdrawchar(void) {
display.clearDisplay();
display.setTextSize(1); // Normal 1:1 pixel scale
display.setTextColor(SSD1306_WHITE); // Draw white text
display.setCursor(0, 0); // Start at top-left corner
display.cp437(true); // Use full 256 char 'Code Page 437' font
// Not all the characters will fit on the display. This is normal.
// Library will draw what it can and the rest will be clipped.
for(int16_t i=0; i<128; i++) {
if(i == '\n') display.write(' ');
else display.write(i);
}
display.display();
delay(1000);
}
void err_msg(){
// Show the error message on the SSD1306 screen.
display.clearDisplay();
display.drawBitmap(48, 0, _error, 32, 32, SSD1306_WHITE);
display.setTextSize(1);
display.setTextColor(SSD1306_WHITE);
display.setCursor(0,40);
display.println("Check the serial monitor to see the error!");
display.display();
}
void testdrawstyles(void) {
display.clearDisplay();
display.setTextSize(1); // Normal 1:1 pixel scale
display.setTextColor(SSD1306_WHITE); // Draw white text
display.setCursor(0,0); // Start at top-left corner
display.println(F("Hello, DUDE!! "));
display.setTextColor(SSD1306_BLACK, SSD1306_WHITE); // Draw 'inverse' text
display.println(3.141592);
display.setTextSize(2); // Draw 2X-scale text
display.setTextColor(SSD1306_WHITE);
display.print(F("0x")); display.println(0xDEADBEEF, HEX);
display.display();
delay(500);
}
void testscrolltext(void) {
display.clearDisplay();
display.setTextSize(1); // Draw 2X-scale text
display.setTextColor(SSD1306_WHITE);
display.setCursor(10, 0);
display.print(F("Temp Is\n"));
display.display(); // Show initial text
delay(100);
// Scroll in various directions, pausing in-between:
display.startscrollright(0x00, 0x0F);
delay(2300);
display.stopscroll();
delay(200);
display.startscrollleft(0x00, 0x0F);
delay(2500);
display.stopscroll();
display.setTextColor(SSD1306_BLACK);
display.setCursor(10, 0);
display.print("Temp Is");
display.display(); // Show initial text
delay(300);
display.setTextColor(SSD1306_WHITE);
display.setTextSize(2); // Draw 2X-scale text
display.setCursor(0, 10);
float ctemp = 98.6;
delay(250);
display.print(ctemp);
display.print(" ");
display.setTextSize(1);
display.print("F");
delay(2000);
display.display();
delay(2000);
display.startscrolldiagright(0x00, 0x07);
delay(2000);
display.startscrolldiagleft(0x00, 0x07);
delay(2000);
display.stopscroll();
delay(2000);
}
void testdrawbitmap(void) {
display.clearDisplay();
display.drawBitmap(
(display.width() - LOGO_WIDTH ) / 2,
(display.height() - LOGO_HEIGHT) / 2,
logo_bmp, LOGO_WIDTH, LOGO_HEIGHT, 1);
display.display();
delay(1000);
}
#define XPOS 0 // Indexes into the 'icons' array in function below
#define YPOS 1
#define DELTAY 2
void testanimate(const uint8_t *bitmap, uint8_t w, uint8_t h) {
int8_t f, icons[NUMFLAKES][3];
// Initialize 'snowflake' positions
for(f=0; f< NUMFLAKES; f++) {
icons[f][XPOS] = random(1 - LOGO_WIDTH, display.width());
icons[f][YPOS] = -LOGO_HEIGHT;
icons[f][DELTAY] = random(1, 6);
Serial.print(F("x: "));
Serial.print(icons[f][XPOS], DEC);
Serial.print(F(" y: "));
Serial.print(icons[f][YPOS], DEC);
Serial.print(F(" dy: "));
Serial.println(icons[f][DELTAY], DEC);
}
for(;;) { // Loop forever...
display.clearDisplay(); // Clear the display buffer
// Draw each snowflake:
for(f=0; f< NUMFLAKES; f++) {
display.drawBitmap(icons[f][XPOS], icons[f][YPOS], bitmap, w, h, SSD1306_WHITE);
}
display.display(); // Show the display buffer on the screen
delay(200); // Pause for 1/10 second
// Then update coordinates of each flake...
for(f=0; f< NUMFLAKES; f++) {
icons[f][YPOS] += icons[f][DELTAY];
// If snowflake is off the bottom of the screen...
if (icons[f][YPOS] >= display.height()) {
// Reinitialize to a random position, just off the top
icons[f][XPOS] = random(1 - LOGO_WIDTH, display.width());
icons[f][YPOS] = -LOGO_HEIGHT;
icons[f][DELTAY] = random(1, 6);
}
}
}
}
HTH
GL 
PJ 