Cannot display Atlas Scientific probe readings to OLED display, please help

I am working on a school project (environmental engineering) that requires using a DO probe to make measurements. I have tested both the probe and the screen with sample codes; both are working perfectly. However, I cannot get the probe to display its readings to the OLED screen. If I cannot get the screen to work, I will have to drive around and take readings near bridges (rather boring) with the probe hooked up to my laptop. If I can get the screen working, I will be able to kayak down the river and take more measurements.

I have been trying to make the sample code output the readings to the OLED display rather than the serial monitor. I watched several videos and read a few articles trying to figure out how to make the probe display its results with no luck. All of my attempts result in errors or the screen not displaying anything at all. I am using the AdafruitSSD1306 library for the OLED display and showed the codes I used below. Looking at the rules I have made a quick schematic, but I don't believe it is needed.

(EZ DO probe circuit and probe pictures left, Arduino Uno pictured middle, OLED display pictured right)

The screen is not mandatory and my professor is fine with just using serial monitor readings, but I would prefer to use the screen. I will gladly credit anyone who helps me fix the code in the paper my group writes (as long as your reddit name is appropriate for school paper), but only my professor will be reading it.

Thanks for taking the time to read this!

This is the sample code for the Atlas Scientific DO probe that works with the serial monitor:

//This code was written to be easy to understand. //Modify this code as you see fit. //This code will output data to the Arduino serial monitor. //Type commands into the Arduino serial monitor to control the D.O. circuit. //This code was written in the Arduino 1.8.9 IDE //An Arduino UNO was used to test this code. //This code was last tested 6/2019 #include <SoftwareSerial.h> //we have to include the SoftwareSerial library, or else we can't use it #define rx 2 //define what pin rx is going to be #define tx 3 //define what pin tx is going to be SoftwareSerial myserial(rx, tx); //define how the soft serial port is going to work String inputstring = ""; //a string to hold incoming data from the PC String sensorstring = ""; //a string to hold the data from the Atlas Scientific product boolean input_string_complete = false; //have we received all the data from the PC boolean sensor_string_complete = false; //have we received all the data from the Atlas Scientific product float DO; //used to hold a floating point number that is the DO void setup() { //set up the hardware Serial.begin(9600); //set baud rate for the hardware serial port_0 to 9600 myserial.begin(9600); //set baud rate for the software serial port to 9600 inputstring.reserve(10); //set aside some bytes for receiving data from the PC sensorstring.reserve(30); //set aside some bytes for receiving data from Atlas Scientific product } void serialEvent() { //if the hardware serial port_0 receives a char inputstring = Serial.readStringUntil(13); //read the string until we see a <CR> input_string_complete = true; //set the flag used to tell if we have received a completed string from the PC } void loop() { //here we go... if (input_string_complete == true) { //if a string from the PC has been received in its entirety myserial.print(inputstring); //send that string to the Atlas Scientific product myserial.print('\r'); //add a <CR> to the end of the string inputstring = ""; //clear the string input_string_complete = false; //reset the flag used to tell if we have received a completed string from the PC } if (myserial.available() > 0) { //if we see that the Atlas Scientific product has sent a character char inchar = (char)myserial.read(); //get the char we just received sensorstring += inchar; //add the char to the var called sensorstring if (inchar == '\r') { //if the incoming character is a <CR> sensor_string_complete = true; //set the flag } } if (sensor_string_complete == true) { //if a string from the Atlas Scientific product has been received in its entirety Serial.println(sensorstring); //send that string to the PC's serial monitor /* //uncomment this section to see how to convert the DO reading from a string to a float if (isdigit(sensorstring[0])) { //if the first character in the string is a digit DO = sensorstring.toFloat(); //convert the string to a floating point number so it can be evaluated by the Arduino if (DO >= 6.0) { //if the DO is greater than or equal to 6.0 Serial.println("high"); //print "high" this is demonstrating that the Arduino is evaluating the DO as a number and not as a string } if (DO <= 5.99) { //if the DO is less than or equal to 5.99 Serial.println("low"); //print "low" this is demonstrating that the Arduino is evaluating the DO as a number and not as a string } } */ sensorstring = ""; //clear the string sensor_string_complete = false; //reset the flag used to tell if we have received a completed string from the Atlas Scientific product } } 

This is the example code from Adafruit that I used to make sure the OLED display was working (SSD1306_128x64_i2c):

/************************************************************************** This is an example for our Monochrome OLEDs based on SSD1306 drivers Pick one up today in the adafruit shop! ------> http://www.adafruit.com/category/63_98 This example is for a 128x64 pixel display using I2C to communicate 3 pins are required to interface (two I2C and one reset). Adafruit invests time and resources providing this open source code, please support Adafruit and open-source hardware by purchasing products from Adafruit! Written by Limor Fried/Ladyada for Adafruit Industries, with contributions from the open source community. BSD license, check license.txt for more information All text above, and the splash screen below must be included in any redistribution. **************************************************************************/ #include <SPI.h> #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) // The pins for I2C are defined by the Wire-library. // On an arduino UNO: A4(SDA), A5(SCL) // On an arduino MEGA 2560: 20(SDA), 21(SCL) // On an arduino LEONARDO: 2(SDA), 3(SCL), ... #define OLED_RESET 4 // Reset pin # (or -1 if sharing Arduino reset pin) #define SCREEN_ADDRESS 0x3D ///< See datasheet for Address; 0x3D for 128x64, 0x3C for 128x32 Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET); #define NUMFLAKES 10 // Number of snowflakes in the animation example #define LOGO_HEIGHT 16 #define LOGO_WIDTH 16 static const unsigned char PROGMEM logo_bmp[] = { B00000000, B11000000, B00000001, B11000000, B00000001, B11000000, B00000011, B11100000, B11110011, B11100000, B11111110, B11111000, B01111110, B11111111, B00110011, B10011111, B00011111, B11111100, B00001101, B01110000, B00011011, B10100000, B00111111, B11100000, B00111111, B11110000, B01111100, B11110000, B01110000, B01110000, B00000000, B00110000 }; void setup() { Serial.begin(9600); // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) { Serial.println(F("SSD1306 allocation failed")); for(;;); // Don't proceed, loop forever } // Show initial display buffer contents on the screen -- // the library initializes this with an Adafruit splash screen. 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(2000); // display.display() is NOT necessary after every single drawing command, // unless that's what you want...rather, you can batch up a bunch of // drawing operations and then update the screen all at once by calling // display.display(). These examples demonstrate both approaches... testdrawline(); // Draw many lines testdrawrect(); // Draw rectangles (outlines) testfillrect(); // Draw rectangles (filled) testdrawcircle(); // Draw circles (outlines) testfillcircle(); // Draw circles (filled) testdrawroundrect(); // Draw rounded rectangles (outlines) testfillroundrect(); // Draw rounded rectangles (filled) testdrawtriangle(); // Draw triangles (outlines) testfilltriangle(); // Draw triangles (filled) 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(1000); display.invertDisplay(false); delay(1000); testanimate(logo_bmp, LOGO_WIDTH, LOGO_HEIGHT); // Animate bitmaps } void loop() { } void testdrawline() { int16_t i; display.clearDisplay(); // Clear display buffer for(i=0; i<display.width(); i+=4) { display.drawLine(0, 0, i, display.height()-1, SSD1306_WHITE); display.display(); // Update screen with each newly-drawn line delay(1); } for(i=0; i<display.height(); i+=4) { display.drawLine(0, 0, display.width()-1, i, SSD1306_WHITE); display.display(); delay(1); } delay(250); display.clearDisplay(); for(i=0; i<display.width(); i+=4) { display.drawLine(0, display.height()-1, i, 0, SSD1306_WHITE); display.display(); delay(1); } for(i=display.height()-1; i>=0; i-=4) { display.drawLine(0, display.height()-1, display.width()-1, i, SSD1306_WHITE); display.display(); delay(1); } delay(250); display.clearDisplay(); for(i=display.width()-1; i>=0; i-=4) { display.drawLine(display.width()-1, display.height()-1, i, 0, SSD1306_WHITE); display.display(); delay(1); } for(i=display.height()-1; i>=0; i-=4) { display.drawLine(display.width()-1, display.height()-1, 0, i, SSD1306_WHITE); display.display(); delay(1); } delay(250); display.clearDisplay(); for(i=0; i<display.height(); i+=4) { display.drawLine(display.width()-1, 0, 0, i, SSD1306_WHITE); display.display(); delay(1); } for(i=0; i<display.width(); i+=4) { display.drawLine(display.width()-1, 0, i, display.height()-1, SSD1306_WHITE); display.display(); delay(1); } delay(2000); // Pause for 2 seconds } void testdrawrect(void) { display.clearDisplay(); for(int16_t i=0; i<display.height()/2; i+=2) { display.drawRect(i, i, display.width()-2*i, display.height()-2*i, SSD1306_WHITE); display.display(); // Update screen with each newly-drawn rectangle delay(1); } delay(2000); } void testfillrect(void) { display.clearDisplay(); for(int16_t i=0; i<display.height()/2; i+=3) { // The INVERSE color is used so rectangles alternate white/black display.fillRect(i, i, display.width()-i*2, display.height()-i*2, SSD1306_INVERSE); display.display(); // Update screen with each newly-drawn rectangle delay(1); } delay(2000); } void testdrawcircle(void) { display.clearDisplay(); for(int16_t i=0; i<max(display.width(),display.height())/2; i+=2) { display.drawCircle(display.width()/2, display.height()/2, i, SSD1306_WHITE); display.display(); delay(1); } delay(2000); } void testfillcircle(void) { display.clearDisplay(); for(int16_t i=max(display.width(),display.height())/2; i>0; i-=3) { // The INVERSE color is used so circles alternate white/black display.fillCircle(display.width() / 2, display.height() / 2, i, SSD1306_INVERSE); display.display(); // Update screen with each newly-drawn circle delay(1); } delay(2000); } void testdrawroundrect(void) { display.clearDisplay(); for(int16_t i=0; i<display.height()/2-2; i+=2) { display.drawRoundRect(i, i, display.width()-2*i, display.height()-2*i, display.height()/4, SSD1306_WHITE); display.display(); delay(1); } delay(2000); } void testfillroundrect(void) { display.clearDisplay(); for(int16_t i=0; i<display.height()/2-2; i+=2) { // The INVERSE color is used so round-rects alternate white/black display.fillRoundRect(i, i, display.width()-2*i, display.height()-2*i, display.height()/4, SSD1306_INVERSE); display.display(); delay(1); } delay(2000); } void testdrawtriangle(void) { display.clearDisplay(); for(int16_t i=0; i<max(display.width(),display.height())/2; i+=5) { display.drawTriangle( display.width()/2 , display.height()/2-i, display.width()/2-i, display.height()/2+i, display.width()/2+i, display.height()/2+i, SSD1306_WHITE); display.display(); delay(1); } delay(2000); } void testfilltriangle(void) { display.clearDisplay(); for(int16_t i=max(display.width(),display.height())/2; i>0; i-=5) { // The INVERSE color is used so triangles alternate white/black display.fillTriangle( display.width()/2 , display.height()/2-i, display.width()/2-i, display.height()/2+i, display.width()/2+i, display.height()/2+i, SSD1306_INVERSE); display.display(); delay(1); } delay(2000); } 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<256; i++) { if(i == '\n') display.write(' '); else display.write(i); } display.display(); delay(2000); } 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, world!")); 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(2000); } void testscrolltext(void) { display.clearDisplay(); display.setTextSize(2); // Draw 2X-scale text display.setTextColor(SSD1306_WHITE); display.setCursor(10, 0); display.println(F("scroll")); display.display(); // Show initial text delay(100); // Scroll in various directions, pausing in-between: display.startscrollright(0x00, 0x0F); delay(2000); display.stopscroll(); delay(1000); display.startscrollleft(0x00, 0x0F); delay(2000); display.stopscroll(); delay(1000); display.startscrolldiagright(0x00, 0x07); delay(2000); display.startscrolldiagleft(0x00, 0x07); delay(2000); display.stopscroll(); delay(1000); } 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); } } } } 

Touch here for the full post on the Arduino Apprentices tumblr

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