Problems to arrange incoming Data in array

I am using Simulink on a Raspberry Pi and request Data from an Arduino via Serial Communication and Receive an 18x1 uint8 array. I want to split the Array into 6 different double variables and wirte them into an n x 5 array.

Since the Pi receives a continious stream of Data I have a * at the beginnig of my array to determine that there is data in that array. It looks like that:

MessageReceived = [42;49;54;56;55;49;51;48;52;51;53;49;48;48;48;49;56;56];

The MATLAB function in my Simulink model that handles the data has following code:

function [Fahrspur, SpurFreigabe]  = fcn(MessageReceived)

persistent counter;
persistent NachrichtAusgelesenTmp;
persistent FahrspurBuffer;
if isempty(counter)
    counter = 0;
    NachrichtAusgelesenTmp = zeros(500,5);
    FahrspurBuffer = zeros(500,5);
end

% Setup
Geschwindigkeit = 0;
Fahrspur = zeros(1,5);

% read and reconditioning of the data
MessageReceivedChar = char(transpose(MessageReceived));
MessageReceivedStr = string(MessageReceivedChar);
if MessageReceivedChar(1,1) == '*'
    counter = counter + 1;
    xKoordinate = real(str2double(string(MessageReceivedChar(2:6))))/100;
    yKoordinate = real(str2double(string(MessageReceivedChar(7:11))))/100;
    Fahrtrichtung = real(str2double(string(MessageReceivedChar(12))));
    MaehwerkStatus = real(str2double(string(MessageReceivedChar(13))));
    Radius_VZ = real(str2double(string(MessageReceivedChar(14))));   
    Radius = real(str2double(string(MessageReceivedChar(15:18))))/100; 
    % binary into values
    if Fahrtrichtung == 1
        Geschwindigkeit = 0.28;
    elseif Fahrtrichtung == 0
        Geschwindigkeit = -0.28;
    end
    % some change in units
    VorsteuerungKappaBahn = 1/Radius;
    NachrichtAusgelesenTmp(counter,:) = [xKoordinate yKoordinate MaehwerkStatus Geschwindigkeit VorsteuerungKappaBahn];
elseif MessageReceivedStr == "AlleDatenGesendet_"   % Dataset completely receives
    counter = 0;
    idx = find(NachrichtAusgelesenTmp(:,1));
    FahrspurBuffer = NachrichtAusgelesenTmp(1:idx(end),:);
    Fahrspur = FahrspurBuffer;
    SpurFreigabe = true;
end

The Var Fahrspur should be nx5 and containing [xKoordinate yKoordinate MaehwerkStatus Geschwindigkeit VorsteuerungKappaBahn] in each row. The Data in the mat-Log file has all the values for one Var (e.g. xKoordinate) written in a single collum and somewhat later the same happens with the next Var. It's always the first collum and I can't figure out why the data is not sorted like I want it to be. Attached there is an example from my mat-file-logging.

Answer 1

[SAI SRUJAN]

Hi Simon,

I understand that you are facing an issue arranging the incoming data into an array.

Please go through the following code sample below that I utilized to verify the accuracy of the provided code sample.

function [Fahrspur, SpurFreigabe,NachrichtAusgelesenTm]  = fcn(MessageReceived,NachrichtAusgelesenTmp)

    persistent counter;
    persistent FahrspurBuffer;
    if isempty(counter)
        counter = 0;
        NachrichtAusgelesenTmp = zeros(5,5);
        FahrspurBuffer = zeros(500,5);
    end

    % Setup
    Geschwindigkeit = 0;
    Fahrspur = zeros(1,5);
    
    % read and reconditioning of the data
    MessageReceivedChar = char(transpose(MessageReceived));
    MessageReceivedStr = string(MessageReceivedChar);
    if MessageReceivedChar(1,1) == '*'
        counter = counter + 1;
        xKoordinate = real(str2double(string(MessageReceivedChar(2:6))))/100;
        yKoordinate = real(str2double(string(MessageReceivedChar(7:11))))/100;
        Fahrtrichtung = real(str2double(string(MessageReceivedChar(12))));
        MaehwerkStatus = real(str2double(string(MessageReceivedChar(13))));
        Radius_VZ = real(str2double(string(MessageReceivedChar(14))));   
        Radius = real(str2double(string(MessageReceivedChar(15:18))))/100; 
        % binary into values
        if Fahrtrichtung == 1
            Geschwindigkeit = 0.28;
        elseif Fahrtrichtung == 0
            Geschwindigkeit = -0.28;
        end
        % some change in units
        VorsteuerungKappaBahn = 1/Radius;
        NachrichtAusgelesenTmp(counter,:) = [xKoordinate yKoordinate MaehwerkStatus Geschwindigkeit VorsteuerungKappaBahn];
        counter
        NachrichtAusgelesenTm=NachrichtAusgelesenTmp;
        SpurFreigabe = false;
    elseif MessageReceivedStr == "AlleDatenGesendet_"   % Dataset completely receives
        counter = 0;
        idx = find(NachrichtAusgelesenTmp(:,1));
        FahrspurBuffer = NachrichtAusgelesenTmp(1:idx(end),:);
        Fahrspur = FahrspurBuffer;
        SpurFreigabe = true;
        NachrichtAusgelesenTm=NachrichtAusgelesenTmp;
    end
end
MessageReceived = [42;49;54;56;55;49;51;48;52;51;53;49;48;48;48;49;56;56];
ProcessedMessagesArray = zeros(5,5);

for i = [1:5]
    [a, b, ProcessedMessagesArray] = fcn(MessageReceived, ProcessedMessagesArray);
end

counter = 1

counter = 2

counter = 3

counter = 4

counter = 5

ProcessedMessagesArray

ProcessedMessagesArray = 5x5

168.7100 304.3500 0 0.2800 0.5319 168.7100 304.3500 0 0.2800 0.5319 168.7100 304.3500 0 0.2800 0.5319 168.7100 304.3500 0 0.2800 0.5319 168.7100 304.3500 0 0.2800 0.5319

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save('myArrayFile.mat', 'ProcessedMessagesArray');

It is evident that the variable "ProcessedMessagesArray" is accurately calculated, and the 'counter' is appropriately updated and saved into the MAT file, "myArrayFile.mat". To address the issue you're facing, please ensure that the 'elseif' statement correctly identifies the end of the dataset and that the data is being correctly written to the '.mat' file.

I hope this helps!