Simple serial input to enter Byte, Int etc. variables

Projects Programming
1

Hi, I nearly can't believe it.
Is there no simple command to read data from serial input ?
Example: The user types 123 and terminates the entry by pressing ENTER or CR.
The routine waits until ENTER or CR is pressed.
Result: A variable (byte, int, etc.) filled with the value 123.

Other languages can do that with a simple command like :
"Input "Enter Value: )" , var"
This prints "Enter Value: " and waits for the input, to be terminated as said above.

With the C-Type Ardunio language - Does one really has to handle the input buffers, collect the char(s), make them into a string, find the terminating char, remove it from the string, use .toint() to change it into byte, int, etc. ? Can't believe it.

Hoping to have missed some really nice command(s) :wink: Anyone with suggestions ? Thanks !

2

There is (.parseInt()), but it's a blocking function so I would suggest not to use it. Remember it's just a micro-controller!

Might get away with blocking the rest once you received at least a byte untill you start listening but better to look at Robin2's Serial Input Basics.

Although granted, a nice library to wrap it should be nice :slight_smile:

3

What's wrong with...

void loop()
{
    int x = 0;
    if (Serial.available())
    {
         x = Serial.parseInt();
    }
}

Only blocks if there is something to read from Serial.

4

boylesg:
Only blocks if there is something to read from Serial.

Which is a pretty long time for the Arduino, especially if some time passes between digit's (over which you have no control) Like I said, might get away with it but it is wasteful and blocking.

5

Thanks so far for the replies.
"Blocking" would be welcome !
All time critical tasks are handled by interrupts anyway (should never be in the main loop anyway).
What's wrong with

[i]int x = 0;
    if (Serial.available())
    {
         x = Serial.parseInt();
    }[/i]

?
Well that's not even half of what my Input-example does. And, let's say, there a 3 values to be entered, let's call the X, Y and Z
With my Input-Example I would write

Input "Enter X", x
Input "Enter Y", y
Input "Enter Z", z

And the program would wait nicely until x, y and z are entered.
How would that work with

 if (Serial.available())
    {
         x = Serial.parseInt();
    }
 if (Serial.available())
    {
         y = Serial.parseInt();
    }
 if (Serial.available())
    {
         z = Serial.parseInt();
    }

I wonder ?

As the routines don't wait until all numbers for X have been entered, it just goes through the loop all the time.

And, yes, I know about the "Serial Input Basics". That's why I said I can't believe that it is so fiddly and awkward to do a simple job like reading one or more bytes with this C-type language. Reminds me a bit of the "good old times" when I used punch-cards with IBM 029 :wink:

6

septillion:
Although granted, a nice library to wrap it should be nice :slight_smile:

I won't charge royalties if you decide to write the library :slight_smile:

Personally, I prefer to present the code in a way in which the user can see it clearly rather than hiding it in a library.

...R

7

Well, as there seems to be no "real" command to do this and even creating a special library for a simple input-routine has been suggested, could someone please suggest how I could implement
the above described input-function:
... do something
Input var x and wait for CR or LF
... do something
Input var x and wait for CR or LF
... do something
Input more vars

Thanks very much for the kind assistance, guess I'm spoiled by other languages :wink:
I'm really stuck with this problem.
Still can't believe that there is no command for such an trivial and ordinary task. Does no one
enter any values ?! Can't be all hardcoded ?!
Setting an IP-Adress for example. Okay, that would happen in one place of the program and not in separate sections and one might tinker with this serial parse command (is that blocking?)

8

Greece2001:
Setting an IP-Adress for example. Okay, that would happen in one place of the program and not in separate sections and one might tinker with this serial parse command (is that blocking?)

It's not clear to me what you're asking. By "this serial parse command", do you mean parseInt()? If so, why not just write that? It's already been said several times earlier in the thread that function is blocking so I guess you're asking something else, but I don't know what.

9

yep, that's the one. parseInt().

But look what I found :
https://arduino-projekte.webnode.at/meine-libraries/serieller-monitor/
One can select the expected type of var (byte, Int16, float, etc.) and choose
between blocking (great! That's what I needed!) and non-blocking.
Problem solved and maybe not only for me (no need to write a lib, there is this one ...)

Thanks for all your comments !

10

Greece2001:
yep, that's the one. parseInt().

But look what I found :
https://arduino-projekte.webnode.at/meine-libraries/serieller-monitor/
One can select the expected type of var (byte, Int16, float, etc.) and choose
between blocking (great! That's what I needed!) and non-blocking.
Problem solved and maybe not only for me (no need to write a lib, there is this one ...)

Thanks for all your comments !

the library does nothing else then

    int x = 0;
    if (Serial.available())
    {
         x = Serial.parseInt();
    }

you can use parseFloat(), readBytesUntil(), readBytes()

or
you could read a whole line into a buffer and then use sscanf or parse the buffer with strtok

IPAddress has function fromString

13

Delta_G:
Oh look, and here it is the same code in Python. (in the else of the try)

[.......]

I'm absolutely certain I've got it in Java too. I'll run into it eventually.

Interesting, but I don't understand the point you are making.

...R

15

Delta_G:
It’s useful not just in Arduino land.

I agree.

Thanks for the clarification.

...R