I2c old screen not working properly

Thread Starter

quique123

Joined May 15, 2015
405
I started following this tutorial here:
https://how2electronics.com/pulse-sensor-with-oled-arduino/

which uses a pulse sensor, buzzer and a 0.96" oled display and SSD1306 drivers. Except their display is different. Im using this one:
https://github.com/jandelgado/arduino/wiki/SSD1306-based-OLED-connected-to-Arduino.

I tried this sample sketch from that SSD1306 site: https://github.com/jandelgado/ardui...6_sample_adafruit/ssd1306_sample_adafruit.ino

but I only get half of the message on the screen as seen in the image below.

When I upload my final code I get some garbled pixels as seen in the other image below.

Is it a library issue?

This is my code:
C-like:
//added by me
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>

#define OLED_MOSI  11   //D1
#define OLED_CLK   12   //D0
#define OLED_DC    9
#define OLED_CS    8
#define OLED_RESET 10
//end

#include <Adafruit_SSD1306.h>
#define OLED_Address 0x3C // 0x3C device address of I2C OLED. Few other OLED has 0x3D
//Adafruit_SSD1306 oled(128, 64); // create our screen object setting resolution to 128x64

//added from (https://github.com/jandelgado/arduino/blob/master/ssd1306_sample_adafruit/ssd1306_sample_adafruit.ino)by me
Adafruit_SSD1306 oled(OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);
//

int a=0;
int lasta=0;
int lastb=0;
int LastTime=0;
int ThisTime;
bool BPMTiming=false;
bool BeatComplete=false;
int BPM=0;
#define UpperThreshold 560
#define LowerThreshold 530

void setup() {
  oled.begin(SSD1306_SWITCHCAPVCC, OLED_Address);
  oled.clearDisplay();
  oled.setTextSize(2);
}

void loop(){
  if(a>127) {
    oled.clearDisplay();
    a=0;
    lasta=a;
  }

  ThisTime=millis();
  int value=analogRead(0);
  oled.setTextColor(WHITE);
  int b=60-(value/16);
  oled.writeLine(lasta,lastb,a,b,WHITE);
  lastb=b;
  lasta=a;

  if(value>UpperThreshold) {
    if(BeatComplete) {
      BPM=ThisTime-LastTime;
      BPM=int(60/(float(BPM)/1000));
      BPMTiming=false;
      BeatComplete=false;
      tone(8,1000,250);
      }
  if(BPMTiming==false)
  {
  LastTime=millis();
  BPMTiming=true;
  }
  }
  if((value<LowerThreshold)&(BPMTiming))
  BeatComplete=true;
 
  oled.writeFillRect(0,50,128,16,BLACK);
  oled.setCursor(0,50);
  oled.print("BPM:");
  oled.print(BPM);
 
  oled.display();
  a++;
}
E1B90C52-DFD7-4D76-9F11-7D3D5BC908E9.pngF22E5DEE-DDE6-4872-AA5B-FA83545FD2E9.png
 

SamR

Joined Mar 19, 2019
4,292
I suspect your problem is here:
oled.writeFillRect(0,50,128,16,BLACK);
oled.setCursor(0,50);

My experience with OLED tutorials have required me to do some screen size editing. Play with it and see if it changes the on-screen display size.
 

Thread Starter

quique123

Joined May 15, 2015
405
ok i just made a change to the ssd1306 library. I had changed the parameter to #define SSD1306_96_16 but I changed it back to the original #define SSD1306_128_64 and it got way better. I do get the right screen now, somtimes. After a few touches it goes crazy:
FE356A10-AC18-465B-A9BD-9D5C66E2DE66.jpeg808F209D-CEEB-43BF-B839-ADD9AB26A99E.jpeg
 

dendad

Joined Feb 20, 2016
4,167
I found that the oled.display(); command needed to be added after each oled access.
Also, have you tried oled.setTextSize(1); instead of (2)?
What is the actual resolution of your display?

Ah. I see you are getting some progress.
If it is built on breadboard with jumper leads, that may introduce funny problems as they are not a real reliable way to build things.
A better way to go is soldering it all on proto board to ensure cood connections.
 
Last edited:
Top