Problems running dual OLED I2C

Projects Programming
1

Hi
I'm trying to make a thermometer with two OLEDs connected with I2C. I have changed the address of one of them, and i can display proper info on one or the other, but not on both simultaneously.

I was going through different videos, or examples, but nothing seems to work.
Maybe there is something wrong with my code, or my displays, or arduino:

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <DallasTemperature.h>
#define ONE_WIRE_BUS 3
OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);
DeviceAddress T1 = { 0x28, 0xFF, 0x91, 0x37, 0x62, 0x17, 0x04, 0xF5 };
DeviceAddress T2 = { 0x28, 0xFF, 0x77, 0xAA, 0x61, 0x17, 0x04, 0x2B };
float temp1;
float temp2;


//software i2C;
#define OLED_RESET 4
Adafruit_SSD1306 Display1(OLED_RESET);
Adafruit_SSD1306 Display2(OLED_RESET);


void setup()
{
  Display2.begin(SSD1306_SWITCHCAPVCC, 0x3c);
  Display2.clearDisplay();
  Display2.display();

  Display1.begin(SSD1306_SWITCHCAPVCC, 0x3d);
  Display1.clearDisplay();
  Display1.display();
sensors.begin();

}

void loop()
{
sensors.requestTemperatures(); //Polls the sensors
 temp1 = sensors.getTempC(T1);
 temp2 = sensors.getTempC(T2);

//Display1.setTextColor(WHITE);
//Display1.setTextSize(2);
//Display1.setCursor(0,0);
//Display1.println("Temp1");
//Display1.setTextSize(3);
//Display1.println(temp1);
//Display1.setCursor(0,30);
//Display1.setCursor(105,30);
//Display1.println("C");
//Display1.display();
//Display1.clearDisplay();


Display2.setTextColor(WHITE);
Display2.setTextSize(2);
Display2.setCursor(0,0);
Display2.println("Temp2");
Display2.setTextSize(3);
Display2.println(temp2);
Display2.setCursor(0,30);
Display2.setCursor(105,30);
Display2.println("C");
Display2.display();
Display2.clearDisplay();
}
2

Have you tried using a different reset pin for the two displays?

3

I've had the same problem using that OLED library and solved by using the U8G2 library, on an ESP32.

// Bus 1 : les 2 écrans
#define SDA1 19
#define SCL1 23

U8G2_SH1106_128X64_NONAME_F_SW_I2C display1(U8G2_R0, SCL1, SDA1);
U8G2_SH1106_128X64_NONAME_F_SW_I2C display2(U8G2_R0, SCL1, SDA1);

in the setup:

  // Ecrans
  display1.setI2CAddress(0x3C * 2);
  display2.setI2CAddress(0x3D * 2);
  display1.begin();
  display2.begin();

Then calling the display stuff...

4 
U8G2_SH1106_128X64_NONAME_F_SW_I2C display1(U8G2_R0, SCL1, SDA1);
U8G2_SH1106_128X64_NONAME_F_SW_I2C display2(U8G2_R0, SCL1, SDA1);

This is not the same driver chip as the OP is using!

5

That's what I said in introduction. I believe it doesn't work with his library.

Of course, he needs to keep A4 & A5 for I2C connexion

6

That's what I said in introduction. I believe it doesn't work with his library.

In which introduction did you say that you were using a different chip so your solution won't work for OP's setup?

7

I said:

I've had the same problem using that OLED library and solved by using the U8G2 library, on an ESP32.

I just offered an alternative solution, that I supposed would work, based on previous experience.
Whatever, the OP seems far away now...

8

I've had the same problem using that OLED library

U8G2_SH1106_128X64_NONAME_F_SW_I2C display1(U8G2_R0, SCL1, SDA1);
U8G2_SH1106_128X64_NONAME_F_SW_I2C display2(U8G2_R0, SCL1, SDA1);

If you're using a SSD1306 library for an SH1106 display it's no surprise that you got problems. That's what I meant.

But I agree, OP seems not to be interested in a solution anymore.

9

You're right, I didn't pay attention to that, but it indeed worked like a charm... although I had SSD1306 displays