SDS011 PM sensor not updating

Using Arduino Sensors
1

HI,

this is my first project, and first go at coding, i followed the tutorial Air Quality Analyzer using Arduino and Nova PM Sensor SDS011 to Measure PM2.5 and PM10

but then learned i have a different OLED to the tutorial, mine is connected to I2c.

so basically, i confirmed my sensor works on my pc, and the Arduino nano works. it shows the text, but the it reads zero. im sure it will be a simple fix for you guys, but ive tried to figure it out and its taken me 2 days.

here is the code:

#include <SDS011.h>
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
float p10,p25;
int error;
SDS011 my_sds;
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define I2C_SDA  4
#define I2C_SCL  5
#define SDS011 my_sds;
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

void setup() {
  my_sds.begin(3,4);
  Serial.begin(9600);

  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
    
}
void loop() {
      error; my_sds.read(&p25,&p10);
  if (! error) {
    Serial.println("P2.5: "+String(p25));
    Serial.println("P10:  "+String(p10));
display.setTextSize(2);
display.setTextColor(WHITE);
display.setCursor(0,15);
display.println("PM2.5");
display.setCursor(67,15);
display.println(p25);
display.setCursor(0,40);
display.println("PM10");
display.setCursor(67,40);
display.println(p10);
display.display();
display.clearDisplay();
}
delay(1000);
}

the serial monitor, does update, and i can see activity on the Arduino, the sensor is powered, fan operates. also the circuit is connected same as the tutorial, except the modification to the OLED.

2

Try commenting the clearDisplay out. It will likely make a mess on the OLED as values change, but it may allow you to confirm that the display is working.

3

tried that, it does indeed make a mess, but no movement on the screen, shows the Adafruit logo over the PM2.5.

4

I expect clearing the display in setup will get rid of the logo.

5

yep, done that, cleared the logo, but no movement,

oled display looks like this:

PM2.5 0.00
PM10 0.00

6

And yet, the serial monitor shows non-zero values?

I wonder if the display library can't handle float. What if you try printing a literal int e.g. 123.

7

CODE
CODE800×810 107 KB

Im not sure how to print int, can you reply something i can just copy in place? please

8

Your serial output shows the same thing - zeroes. I suspect then that the issue is nothing to do with the display.

What code were you using to test the sensor when you believed it was working?

9

dust sensor viewer, with a USB adaptor direct to pc. when its connected to my pc with correct drivers etc, it works a treat. give the sensor some smoke... numbers jumps up and so on. then plugged it back into the bread board, ran my code. still the same.
i used another code that has moving text, and that worked fine.

im not sure if my code has the uses the correct tx/rx pins,

void setup() {

my_sds.begin(3,4);

10

Can you post the code (and serial output) that was giving non-zero readings?

11

no, it was a application that i downloaded and ran, so im not sure where to get the code for that.

12

Your code looks similar to the library example, so all I can think of is that you have a wiring issue. How is it wired up?

13

so ive wired the sensor to the nano the same as the example,
OLED is:
vcc-5v
GND-GND
SCL-A5
SDA-A4.

SENSOR:
5V-5V
GND-GND
RXD-D3
TXD-D4

14

I suspect that you have RX and TX reversed.

15

that worked,
i tried that before but it didnt work, but now its fixed. thanks for your help.

16

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