a.
I can fit around fit 14 per on the display. I can only fit 6 lines on the display.
Therefore I can only fit a total of 14 * 6 = 84 characters on the display.
b.
3a. Include the code that you had to insert to do this in your lab writeup.
File dataFile = SD.open("datalog.txt", FILE_WRITE);
if (dataFile) {
dataFile.println("He who must not be named");
dataFile.close(); }
b. Explain what would you do differently (or show us your code!) to insert the same text string, but at the beginning of the file (without over-writing the current contents).
To place the same text string at the beginning of the file, I would save whatever was on the SD card, then I would clear the SC card. After that I would paste the string first, followed by the previously saved information which was on the SD.
4a. Post your code.
My setup part of the code:
void setup()
{
// Open serial communications and wait for port to open:
Serial.begin(9600);
delay(1000); //this 1 second delay isn't strictly speaking necessary, but it seems to smooth over the USB serial monitor a bit.
while (!Serial) {
; // wait for serial port to connect. Needed for Leonardo only
}
Serial.print("Initializing SD card...");
pinMode(17, OUTPUT); //set SS pin as output.
// see if the card is present and can be initialized:
if (!SD.begin(chipSelect)) {
Serial.println("Card failed, or not present");
// don't do anything more:
return;
}
Serial.println("card initialized.");
// 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");
// if the file is available, write to it:
if (dataFile) {
display.begin();
display.clearDisplay();
display.setContrast(50);
display.write(dataFile.read());
display.display();
dataFile.close();
}
// if the file isn't open, pop up an error:
else {
Serial.println("error opening datalog.txt");
}
}
5a. Tell us what you had to change to make this work.
I would replace the EEprom functions like read and write with the SD Card.