Question

I’m making a clock with the Arduino, and I want to make a button to set the time.
So, just to test, I pluged a wire in the Analog Input pin 0 and wrote two lines of code to read the pin and print it via Serial, but all I get is junk.

  valm = analogRead(0);
  Serial.println(valm);

And what I get from the serial monitor is this:
?j?d?±µ?Ê??jDd?±µ???ºjRd?±µ???ºj?d?±µ?Ê??j?d?±µ?É?ªjRd?±µ???ÊjRd?±µ???Âj?d?±µ????j?d?±µ?É??j
Rd?±µ????j?d?±µ???ºj?d?±µ?É??jRd?±µ????j?d?±µ?Ê?ÊjDd?±µ???Âj?d?±µ????j?d?±µ?É??jRd?±µ????j?d
?±µ?É?ÂjRd?±µ???Êj?d?±µ???ªj?d?±µ?Ê?Êj$d?±µ???ÂjRd?±µ????j?d?±µ????jdd?±µ????jRd?±µ???Âj?d?±
µ?É?ÊjRd?±µ????j?d?±µ?Ò?Êj?d?±µ?É?ÂjRd?±µ????j?d?±µ????j?d?±µ?É??jRd?±µ???Âj?d?±µ???Êj?d?±µ?
??ªj?d?±µ???Êj?d?±µ???ÂjRd?±µ????j?d?±µ????j?d?±µ?É??jRd?±µ???Âj?d?±µ?Ò?Êj?d?±µ?É?ªj?d?±µ?É?
?jTd?±µ???Âj?d?±µ????j?d?±µ?É??jRd?±µ????j?d?±µ?É?ÂjRd?±µ???Êj?d?±µ?É?ªjRd?±µ???Êj?d?±µ???ºj
?d?±µ?È??jTd?±µ????jRd?±µ???ªj?d?±µ?È?ÂjTd?±µ?É?ÊjRd?±µ???ªj?d?±µ???Êj?d?±µ???ºj?d?±µ?É??jRd
?±µ???Êj?d?±µ???ªj?d?±µ?É?ÂjPd?±µ???Êj?d?±µ???ªj?d?±µ?Â?Êj?d?±µ?É?ºjRd?±µ????j?d?±µ?É??jRd?±
µ???ªj?d?±µ?Ê?Âj?d?±µ???ÊjRd?±µ???ªj?d?±µ?Ò?Êj?d?±µ???ºjRd?±µ????j?d?±µ???Êj?d?±µ?Ê?ªjdd?±µ?
??ÂjRd?±µ???Âj?d?±µ?É?ªjPd?±µ???Êj?d?±µ????j?d?±µ?É??jRd?±µ???Êj?d?±µ?É?ªjdd?±µ???ÂjRd?±µ???
Âj?d?±µ?É?ªjDd?±µ???Êj?d?±µ?Ê??j?d?±µ?É??jRd?±µ???ÊjRd?±µ???ªj?d?±µ?Ê?ÂjPd?±µ???Âj?d?±µ???ªj
?d?±µ?É?Êjdd?±µ?É??jRd?±µ????j?d?±µ?É?Êj$d?±µ???ªjRd?±µ???Âj?d?±µ?Â?ÂjTd?±µ???ªj?d?±µ???Êj?d
?±µ????jRd?±µ????j?d?±µ?É?ÊjTd?±µ???ªjRd?±µ???Âj?d?±µ???Âj?d?±µ?É?ªjRd?±µ???ÊjRd?±µ?Ò??jTd?±
µ????j?d?±µ???Êj

Why?

---

Edit:

I had set the digital pin 0 to output, and I thought maybe that was the problem so I went to the Arduino website and found the page Analog Input Pins.

So I tried to read from pin 14 which they say is the analog input pin 0, but I got the same output.

By the way, I’m trying to read from the analog only pins, not the one wich are also digital.

Answer 1

Try running this sample code found on the Arduino website. You shouldn’t need to convert the variable valm or anything.

/*
  Analog input

    Reads an analog input on analog in 0, and prints the value out.

    Created 24 March 2006
    by Tom Igoe
*/

int analogValue = 0;    // Variable to hold the analog value.

void setup() {
    // open the serial port at 9600 bit/s:
    Serial.begin(9600);
}

void loop() {
    // Read the analog input on pin 0:
    analogValue = analogRead(0);

    // Print it out in many formats:
    Serial.println(analogValue);       // print as an ASCII-encoded decimal
    Serial.println(analogValue, DEC);  // print as an ASCII-encoded decimal
    Serial.println(analogValue, HEX);  // print as an ASCII-encoded hexadecimal
    Serial.println(analogValue, OCT);  // print as an ASCII-encoded octal
    Serial.println(analogValue, BIN);  // print as an ASCII-encoded binary
    Serial.println(analogValue, BYTE); // print as a raw byte value

    // Delay 10 milliseconds before the next reading:
    delay(10);
}

If your output is still gibberish, there’s something wrong with your serial terminal.