Creating a node for sending / receiving data via sound card!

General
41

thats why in my version i only ever call the repeat function in the return of the exec. So it doesnt do anything like that. Did you look at the code i send you in the pm

1 Like
42

So i started working on the listen node , and i have a problem with spawning the minimodem --rx + options + baudmode
I am using child_process-s spawn and i cant configure it to run as it should
After reading the documentation and copying the sample code to mine project i always get an error from minimodem stderr: usage: minimodem [--tx|--rx] [options] {baudmode}

Here is my code:

  function getlisten(options){
        const ls = spawn("minimodem" ,[ options  + " 300" ]);
        node.status({fill:"blue", shape:"dot", text:"Listening!"})
        ls.stdout.on("data", data => {
            console.log(`stdout: ${data}`);
        });
        
        ls.stderr.on("data", data => {
            console.log(`stderr: ${data}`);
        });
        
        ls.on('error', (error) => {
            console.log(`error: ${error.message}`);
        });
        
        ls.on("close", code => {
            console.log(`child process exited with code ${code}`);
        });
        
    }

options is a string (eg: --auto-carrier --confidence 2.5 )
300 should be replaced with baudmode variable.

I tried several different orders but none is working as it should!

43

So aperantly there was a really simple sollution for this :smiley:
Just by adding the ' before and after options string it got working!
const ls = spawn("minimodem" ,[ + "'" + options +"'" + " 300" ]);

44

Normally this shouldnā€™t be necessary and its not really the recommended way. What is true is that the child_process.spawn() exepects an array of arguments with one argument per array element and not one string of options. So it should be something like really to use it correctly : spawn("minimode",["--auto-carrier","--confidence","2.5","300"]);

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45

Okay i will convert the options string to an array and will try again , so far the minimodem executes successfully , but i do not get any data from it :frowning:

46

Can anyone help? Decided to ask a question after being stuck for a whole day...
Stackoverflow Question.

47

Maybe try a function something like this:

let timeout = false;
let outputBufferArr = [];

function timeoutConcat(data){
    
    if(timeout) {
        clearTimeout(timeout);
        timeout = false;
    }
    
    outputBufferArr.push(data);
    
    timeout = setTimeout(()=>{
        let message = Buffer.concat(outputBufferArr);
        console.log(message.toString());
        outputBufferArr = [];
    }, 500);
    
}

which you call from the stdout on data part:

minimodem.stdout.on('data', (data)=>{
    timeoutConcat(data);
});

Not tested at all just wrote down what i think might work logically.
It should in theory log the output of all data received so far as soon as no new data arrives for 500 ms.

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48

Thank you for your quick answer once again sir :slight_smile: Will test it right now

49

i edited the code above, of course the variables need to be declared as let or var and not const :see_no_evil: and it was logging the wrong var too. That happens when you write code free form late at night :joy:

50

Yes i just saw that error

51

Well its working great i think i would experiment with the 500ms delay (probably add a setting for it) so user can edit it.
I took a brake from 7pm to 10pm so i am ready to roll the entire night :joy:

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52

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