i am trying to store numbers like 1,2,3, on integer variables (using serial communication on serial monitor).
The problem is that when i print (serial.println) these variables it shows 49,50,51 and not 1,2,3.
the strange thing is that if i make the varialbe byte (and not int) it works!
any help?
The really strange thing is that this comes up about once a week, and no-one ever does a forum search before posting.
ASCII decimal digits: 0x30 = '0' , 0x31 = '1'...0x39 = '9'
And how do i convert it?
int val = Serial.read() - '0'; will convert any character that represents a digit to the number it represents.
will convert any character that represents a decimal digit
Thanks pauls, very helpfull
does it matter that i have many questions?
will convert any character that represents a decimal digit
What other kinds of digits are there?
does it matter that i have many questions?
No. If it bothered us, we wouldn't be reading them or answering them.
What other kinds of digits are there?
Hex - A to F. 
Hex - A to F.
Oh, yeah. But, they presuppose that the data was sent as based 16 strings, which is kind of unusual.
int nextStep;
int previousStep = 0;
int position;
int search;
int rpm100;
int rpm10;
int rpm1;
int rpm;void setup()
{
Serial.begin(9600);
pinMode(7,OUTPUT);
stepper.setSpeed(300);}
void loop()
{search = Serial.read();
if (search == 'A') {rpm100 = Serial.read()- '0';
rpm10 = Serial.read()- '0';
rpm1 = Serial.read()- '0';rpm = (100rpm100) + (10rpm10) + rpm1;
i am not getting the number
i am sending in a demical/binary/hexademical format from X-sim profiller
the X-sim sends
"A" and a number from 127 to 255
but i am not getting the number
search = Serial.read();
if (search == 'A') {rpm100 = Serial.read()- '0';
rpm10 = Serial.read()- '0';
rpm1 = Serial.read()- '0';rpm = (100rpm100) + (10rpm10) + rpm1;
Serial.write(rpm);
i am typing A200 on the serial monitor and i am not getting "Á" back
Try using Serial.print(rpm), and see what you get. Yes, it will convert the value to a string, but that will tell you whether the value is good.
search = Serial.read();
if (search == 'A') {rpm100 = Serial.read()- '0';
rpm10 = Serial.read()- '0';
rpm1 = Serial.read()- '0';rpm = (100rpm100) + (10rpm10) + rpm1;
Serial.print(rpm);
A000 gives -5439
A001 gives -5439
A220 gives -5439
A255 gives -5439
A2200 gives -5439
A gives -5439
A22 gives -5439
200 gives nothing
WHY?
also when i connect the io bridge Serial LCD to the RX
and send data from the X-Sim i am reading
A125A125A125A125A125
when i connect it to the TX pin so i read the Serial.print(rpm)
i am getting only once -5439
Are you initializing rpm100, rpm10, and rpm1 before storing the Serial.read data into them? Are you waiting for 4 characters to arrive before reading anything? The Serial.read function will return -1 if there is nothing to read. -1 - 48 = -49. -4900 - -490 - -49 = -5439.
Use Serial.available() to ensure that there is data to read, or test that the value read from the serial port is positive before using it.
search = Serial.read();
if (search == 'A') {rpm100 = Serial.read()- '0';
rpm10 = Serial.read()- '0';
rpm1 = Serial.read()- '0';Serial.print(rpm100);
Serial.print(rpm10);
Serial.print(rpm1);rpm = (100rpm100) + (10rpm10) + rpm1;
Serial.print(rpm);
[ch913]220 gives -49-49-49-5439
A000 gives -49-49-49-5439
i just see the second page
#include <Stepper.h>
Stepper stepper(48, 12, 11, 10, 9);
int nextStep;
int previousStep = 0;
int position;
int search;
int rpm100;
int rpm10;
int rpm1;
int rpm;void setup()
{
Serial.begin(9600);
pinMode(7,OUTPUT);
stepper.setSpeed(300);}
void loop()
{search = Serial.read();
if (search == 'A') {rpm100 = Serial.read()- '0';
rpm10 = Serial.read()- '0';
rpm1 = Serial.read()- '0';Serial.print(rpm100);
Serial.print(rpm10);
Serial.print(rpm1);rpm = (100rpm100) + (10rpm10) + rpm1;
Serial.print(rpm);
position = map(rpm,127,255,40,0);
if (position >= 39) digitalWrite(7, HIGH);
nextStep = position - previousStep;
stepper.step(nextStep);
previousStep = position;
if (position < 39) digitalWrite(7, LOW);
}}
what do you mean to intiallise
sry for my english
the X-sim
send with a 33ms delay (i can change that) the "A" and three numbers all the time
thanks
If you are always sending 4 characters, you need to wait until there are 4 characters to read:
void loop()
{
if(Serial.available() >= 4)
{
// Now, we can read the data
}
}
If you are not always sending 4 characters, you need to send some start and end of packet markers:
Then, you need to look for these markers.
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1273230655/2#2
(Read the responses that follow too. I had an error in the code).
i didnt get it
i am always send one character and 3 numbers
those i post above were just tests
where is my mistake
the rpm100 rpm10 and rpm1 should be char and not int
?