Converting byte array or String value to float in P5.js (javascript based)

I have been successful in getting serial data in P5.js sketch using this – GitHub – p5-serial/p5.serialport: Serial Port API and Server for p5.js library as either byte array or string values.

When I tried converting string to float type using float() – I get a lot of NaN values which shouldn’t be coming since data is numerical.

Alternatively, I then tried getting data from serial port as byte array. I can’t find a way to convert this array to my original float value in P5.js.

Any ideas on how to convert byte array to float or avoid getting NaN when converting string to float?

Appreciate your time and help. Thanks.

Codes I have tried for conversion:

  1. From String to float, I used

    let incomingData;
    
    let dataValue;
    
    incomingData = serial.readStringUntil('\n');
    
    dataValue = float(incomingData);  //standard method in P5.js -- returns NaN values
    

I also tried parseFloat() — https://www.geeksforgeeks.org/javascript-parsefloat-function/

  dataValue = parseFloat(incomingData);
  //again returns maximum values as NaN
  1. From byte array to float

    let incomingBytes = [];
    
    let dataValue;
    
    incomingBytes = serial.readBytesUntil('\n');
    
    dataValue = dataView.getFloat64(bytebuffer); 
    // This javascript method is not supported by P5.js it seems
    

original data in arduino
string data in P5.js
NaN after converting to float
array of converted values - a lot of NaN
array of string data without conversion

28 thoughts on “Converting byte array or String value to float in P5.js (javascript based)”

  1. As seen in the last image, there were empty strings or null values coming. I just had to put a check for it before doing the conversion.

    Thanks to all the commenters.

     let incomingData;                    //incoming serial value is stored in this variable
    
     let temparray = [1000];              //temporary array used in updating final array
    
     let plot_from_here = [1000];         //final array of values to plot
     function setup(){}
     function draw(){}
    
     function serialEvent() {
    
      if(serial.available()>0){
    
       incomingData = serial.readStringUntil('\n');    //read string until next line
    
        if(incomingData != ""){
    
         incomingData = trim(incomingData);            //trim white spaces
    
         arrayCopy(temparray,0, temparray,1,999);      //Copy value from index 0 to index 1
    
         temparray[0]= float(incomingData);            //Update index 0 of temparray for the incoming value -- the value is converted to float from string type
    
         plot_from_here = temparray;                   //update values in final array
    
        print(plot_from_here);
    
         }
       }
      }
    
    Reply

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