Hi everyone,
I am using Arduino 1.8.5 software and Arduino MEGA2560 with the SD card shield. For my project, I have to read the voltage and temperature from the pins connected to the board, which later should be saved as a .csv file.
Here is my code:
//SWITCH part of the code
int inPin = 2; // the number of the input pin
int outPin = 13; // the number of the output pin
int state = HIGH; // the current state of the output pin
int reading; // the current reading from the input pin
int previous = LOW; // the previous reading from the input pin
int goButton; // press inPin = 2 to go
// the follow variables are long's because the time, measured in miliseconds,
// will quickly become a bigger number than can be stored in an int.
long time = 0; // the last time the output pin was toggled
long debounce = 200; // the debounce time, increase if the output flickers
#include "SD.h" //includes SD library
#include"SPI.h" //includes SPI library
const int CSpin = 53;
String dataString = ""; // holds the data to be written to the SD card
const float referenceVolts = 5.0; // the default reference on a 5-volt board
const int batteryPin = 0; // battery is connected to analog pin 0
const int temperaturePin = 5; // temperature probe is connected to analogue pin 5 (amp needed)
const int fluxMeterPin = 6; // Fluxmeter (a TEM) is connected to analogue pin 6 (?)
const int pwmPin = 7; // Output voltage to TEM is connected to analogue pin 7 (amp needed)
const int pwmSwitchPin = 4; // Digital to TEM - switches between heating and cooling.
File sensorData;
File myFile;
int myTime = 0;
//
//
void setup()
{
pinMode(inPin, INPUT);
pinMode(outPin, OUTPUT);
Serial.begin(9600);
Serial.print("Initializing SD card...");
pinMode(CSpin, OUTPUT);
Serial.println ("Start of program ");
//
// Check make sure that go switch is off
// The "go button" gives LOW when depressed and HIGH when not depressed.
//
Serial.println ("Depress and then release the go button to start");
goButton = HIGH;
while (goButton==HIGH) {
goButton = digitalRead(inPin);
delay(500);
Serial.print ("Start button value is ");
Serial.println (goButton);
// Serial.println("Switch the start button off");
}
delay(200);
// Now wait until it is on.
//
Serial.println ("Awaiting release of go button");
// Serial.println (goButton);
while (goButton == LOW){
goButton = digitalRead(inPin);
// Serial.print ("Start button value is ");
// Serial.println (goButton);
delay(100);
// Serial.println ("Awaiting go button.");
}
Serial.println ("Operation started");
// see if the card is present and can be initialized:
if (!SD.begin(CSpin)) {
Serial.println("Card failed, or not present");
// don't do anything more:
return;
}
Serial.println("card initialized.");
sensorData = SD.open("myData2.csv", FILE_WRITE);
if (sensorData) {
Serial.print("Writing file header...");
sensorData.println("TEM TEST DATA");
Serial.println("TEM TEST DATA");
// close the file:
sensorData.close();
Serial.println("done.");
} else {
// if the file didn't open, print an error:
Serial.println("error 10 opening data file");
}
}
//
void loop()
{
reading = digitalRead(inPin);
// if the input just went from LOW and HIGH and we've waited long enough
// to ignore any noise on the circuit, toggle the output pin and remember
// the time
if (reading == HIGH && previous == LOW && millis() - time > debounce) {
if (state == HIGH)
state = LOW;
else
state = HIGH;
time = millis();
}
digitalWrite(outPin, state);
previous = reading;
int val = analogRead(batteryPin); // read the value from the sensor
float volts = (val / 1023.0) * referenceVolts; // calculate the ratio
//
// *******************************************************************
//
// Start logging
float mjtTime = millis(); // Time in milli-seconds
//
val = analogRead(temperaturePin); // read the value from the temperature probe.
float temperVolts = (val / 1023.0) * 80; // Wild guess that f.s.d. = 80 deg C. Check this!
//
val = analogRead(fluxMeterPin); // read the value from the sensor
float fmVolts = (val / 1023.0) * referenceVolts; // Wild guess that f.s.d. = 80 deg C. Check this!
//
// Implement simple proportional control with an arbitrary coefficient.
float spError = setPointTemp(millis())- temperVolts; // set point error.
float TEMvolts= spError * 0.1;
//
if (TEMvolts > 0) {
digitalWrite (pwmSwitchPin, 1); // Set hardware to heating mode.
}
else {
digitalWrite (pwmSwitchPin, 0); // Set hardware to cooling mode.
}
//
TEMvolts = abs(TEMvolts); // Lose any negative sign
TEMvolts = max (2, TEMvolts); // Restrict to two volts max
digitalWrite (pwmPin, TEMvolts); // Write voltage to TEM.
// Determine output string
dataString = String(mjtTime)+","+String(temperVolts)+","+String(fmVolts) ;
while (millis() < mjtTime + 1000){
// delay loop
}
Serial.println ("End of delay loop");
myTime = myTime + 1;
// build the data string
//dataString = String(myTime) + "," + String(volts); // convert to CSV
if (myTime < 30) {
saveData();
}
else {
Serial.println ("You can remove the SD card now.");
}
// delay(5000); // delay before next write to SD Card, adjust as required
}
//
void saveData() {
// if (SD.exists("myData2.csv")) { // check the card is still there
// now append new data file
sensorData = SD.open("myData2.csv", FILE_WRITE);
if (sensorData) {
sensorData.println(dataString);
Serial.println(dataString);
sensorData.close(); // close the file
}
// }
else {
Serial.println("Error 20 writing to file !");
}
}
float setPointTemp(float myTime){
// This returns the set point temp as a function of time
float amplitude = 0;
float mean = 25;
float timePeriod = 2400;
// At the moment, the set point is a constant 25 deg C. Eventually we shall make this a sinusoidal function.
// (But lets test it thoroughly first!
float s = mean + sin (6.28amplitudemyTime/timePeriod);
return s;
}
The error is:
Operation started
Card failed, or not present
End of delay loop
Error 20 writing to file !
I will be very grateful for your help.
MJTplayJunklast.ino (5.97 KB)