I get the value of symbols like "#" "$" "!" ect. with bmp280 with hardware SPI.

Using Arduino Sensors
#1

I Have a BMP280 wired up to my Arduino micro like shown in the attachments. When I upload the following code I sometimes get a “#”, “$”, “!”, or whatever symbol it may be, but I don’t know why.

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_BMP280.h>

#define BMP_CS (4)

Adafruit_BMP280 bmp(BMP_CS);

void setup() {
  Serial.begin(9600);

  if (!bmp.begin()) {
    Serial.println(F("Could not find a valid BMP280 sensor, check wiring!"));
  }

  bmp.setSampling(Adafruit_BMP280::MODE_NORMAL,
                  Adafruit_BMP280::SAMPLING_X2,
                  Adafruit_BMP280::SAMPLING_X16,
                  Adafruit_BMP280::FILTER_X16,
                  Adafruit_BMP280::STANDBY_MS_500);
}

void loop() {
  Serial.write("A=");
  Serial.write(bmp.readAltitude(1013.25));
  Serial.write("\n");

  delay(500);

}

I’m kind of new to this but if I were to take a guess I’d think it’s some sort of way of saying something could be wrong with wiring or something like that, though I don’t have any evidence for that. I have also tried wiring up the bmp280 with i2c and software SPI but they did not work either.

Untitled Sketch_bb.jpg
Untitled Sketch_bb.jpg1755×675 251 KB

#2

If by 'I sometimes get' you mean what appears in the Serial monitor, then you might want to check the Arduino reference for Serial.Write, just to make sure your using it correctly.

#3

Replace the Serial.write() with Serial.print() or Serial.println() and it will work a lot better.

Indeed do look up the difference between the two :slight_smile:

#4

write() doesn't do any conversion, it just pushes out 8 bits as is from the internal representation.
You want a human-readable string representing a number, you have to use print().

#5