I am using an example that connects an LCD 1602, an SD memory, DS1307 clock and a DHT22 sensor to an Arduino one, in my case I use an Arduino nano.
I test the operation without enabling the storage in the SD memory and it works correctly, shows the values well, etc.
I just define the memory with the instruction:
SD.begin (chipSelect), strange characters appear and it does not work anymore, the display prints strange characters, some are recognizable, but others are not.
The code is:
#include <SD.h>
#include <LiquidCrystal.h>
#include "DHT.h"
#include <Time.h>
byte thermometer_icon[8] = //icon for termometer
{
B00100,
B01010,
B01010,
B01110,
B01110,
B11111,
B11111,
B01110
};
byte humidity_icon[8] = //icon for water droplet
{
B00100,
B00100,
B01010,
B01010,
B10001,
B10001,
B10001,
B01110,
};
LiquidCrystal lcd(9, 8, 4, 5, 6, 7);
#define DHTPIN A2 // what pin we're connected to
#define DHTTYPE DHT22 // DHT 22 (AM2302)
DHT dht(DHTPIN, DHTTYPE);
const int chipSelect = 10;
char message[]= "Logger";
int previous = 0;
int pos = 0;
void setup() {
// make sure that the default chip select pin is set to
// output, even if you don't use it:
pinMode(chipSelect, OUTPUT);
dht.begin();
lcd.begin(16, 2);
lcd.setCursor(0, 0);
lcd.print(" Data");
lcd.setCursor(0, 1);
lcd.print("Logger");
delay(4000);
Serial.begin(9600);
lcd.createChar(1,thermometer_icon);
lcd.createChar(2,humidity_icon);
lcd.clear();
lcd.print("Initializing SD...");
Serial.print("Initializing SD...\n");
//*******************************************************
if (!SD.begin(chipSelect)) {
// don't do anything more:
Serial.print("SD Fail\n");
return;
}
Serial.print("SD OK\n");
lcd.print("SD initialized.");
delay(4000);
}
//a counter to increase after each reading
int counter = 0;
void loop() {
char val_char[10] ;
// Reading temperature or humidity takes about 250 milliseconds!
// Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
float h = dht.readHumidity();
float t = dht.readTemperature();
float dew = dewPoint(t, h);
// check if returns are valid, if they are NaN (not a number) then something went wrong!
if (isnan(t) || isnan(h)) {
lcd.setCursor(0, 0);
lcd.print("Failed to read from DHT");
Serial.println("Failed to read from DHT");
} else {
// lcd.clear();
lcd.clear();
lcd.setCursor(0, 0);
// lcd.write(2);
lcd.print("H:");
itoa (h, val_char, 10);
lcd.print(val_char);
lcd.print("% ");
lcd.print("T:");
itoa (t, val_char, 10);
lcd.print(val_char);
lcd.print((char)223); //degree sign
lcd.print("C"); //degree sign
lcd.setCursor(0, 1);
// lcd.print("*C");
lcd.print("PRocio:");
itoa (dew, val_char, 10);
lcd.print(val_char);
lcd.print((char)223); //degree sign
lcd.print("C");
Serial.print("Hum: ");
Serial.print(h);
Serial.print(" %\t");
Serial.print("Temperature: ");
Serial.print(t);
Serial.println((char)223); //degree sign
// open the file. note that only one file can be open at a time,
// so you have to close this one before opening another.
File dataFile = SD.open("datalog.txt", FILE_WRITE);
// if the file is available, write to it:
if (dataFile) {
dataFile.print(counter);
dataFile.print(", ");
dataFile.print("Humidity: ");
dataFile.print(h);
dataFile.print(", Temperature: ");
dataFile.print(t);
dataFile.print(", Dew Point: ");
dataFile.print(dew);
dataFile.print("\n");
dataFile.close();
}
// if the file isn't open, pop up an error:
else {
Serial.println("error opening datalog.txt");
}
}
delay(3000);
counter++;
}
/*-----( Declare User-written Functions )-----*/
//
//Celsius to Fahrenheit conversion
double Fahrenheit(double celsius)
{
return 1.8 * celsius + 32;
}
//Celsius to Kelvin conversion
double Kelvin(double celsius)
{
return celsius + 273.15;
}
// dewPoint function NOAA
// reference: http://wahiduddin.net/calc/density_algorithms.htm
double dewPoint(double celsius, double humidity)
{
double A0= 373.15/(273.15 + celsius);
double SUM = -7.90298 * (A0-1);
SUM += 5.02808 * log10(A0);
SUM += -1.3816e-7 * (pow(10, (11.344*(1-1/A0)))-1) ;
SUM += 8.1328e-3 * (pow(10,(-3.49149*(A0-1)))-1) ;
SUM += log10(1013.246);
double VP = pow(10, SUM-3) * humidity;
double T = log(VP/0.61078); // temp var
return (241.88 * T) / (17.558-T);
}
// delta max = 0.6544 wrt dewPoint()
// 5x faster than dewPoint()
// reference: http://en.wikipedia.org/wiki/Dew_point
double dewPointFast(double celsius, double humidity)
{
double a = 17.271;
double b = 237.7;
double temp = (a * celsius) / (b + celsius) + log(humidity/100);
double Td = (b * temp) / (a - temp);
return Td;
}
The captures of the connection diagram and the messages of the Lcd 1602 I add them
Can someone help me solve the problem of strange characters
