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2015-04-07 12:52:22 -0500 commented question String message being cut off.

Okay, after a bit of testing I think that I've narrowed it down to a couple possible causes. 1) and most likely: I was transmitting 4 bytes of floats represented by characters. I think that byte 20 was a 4 in decimal or EOT(end of transmission). 2) some other ending of stream or file character.

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2015-04-01 10:19:00 -0500 commented question String message being cut off.

@gvdhoorn Is that enough?(i edited the question)

2015-04-01 10:18:23 -0500 commented question String message being cut off.

At this point I have abandoned using string to transmit characters, instead I am using Float32MultiArray.

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2015-04-01 10:09:23 -0500 commented question String message being cut off.

@BennyRe the type is std::string

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2015-03-30 21:25:15 -0500 asked a question String message being cut off.

I've been transmitting data in a string, the string is only 24 chars long, but the last 4 chars are being cut off once published as a message. I cannot find an issue.

The string.length() value is 24. Also ROS_INFO() cuts off the last 4 chars too.

Any solutions?

Platform: Rapsberry Pi 2 Model B -- OS: Raspbian (Debian Wheezy) 3.18 -- ROS: Indigo(1.11.10)


void transferSerialData(){
//----- CHECK FOR ANY RX BYTES -----
if (uart0_filestream != -1)
    // Read up to 255 characters from the port if they are there
    unsigned char rx_buffer[256];
    int rx_length = read(uart0_filestream, (void*)rx_buffer, 255);      //Filestream, buffer to store in, number of bytes to read (max)
    if (rx_length < 0)
        //An error occured (will occur if there are no bytes)
    else if (rx_length == 0)
        //No data waiting
    else //process data
        //Bytes received
        rx_buffer[rx_length] = '\0';
        //load bytes into string
        std::string temp;
        for(int i = 0; i < rx_length; i++){
            temp += rx_buffer[i];
        serialDataIn = temp;
        ROS_INFO("i got: %s", rx_buffer);
        if(rx_length >= 4){
        bytesReceived = true;


std_msgs::String serial_raw_msg;
    std::stringstream ss;
    ss << serialDataIn; = ss.str();

receiving program:

void serialCallback(const std_msgs::String::ConstPtr& msg){
    serialDataIn = msg->data.c_str();
    std::cout << serialDataIn << "\n";
    std::cout << serialDataIn.length() << "\n";


this prints out only 20 of the original 24 bytes

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2015-03-07 16:08:53 -0500 asked a question Hector SLAM - Yawing issue + IMU Yaw fusion?

I am using hector slam with an RpLidar (only 5-10 hertz). It works phenomenally well in a straight line, but when I yaw just a little aggressively, hector slam gets confused and doesn't detect a yaw at all. I assume it is due to scan distortions.

(I would upload an image if i could)

My question is if it is possible to manually input a true yaw value when the change in yaw is greater than a certain value?

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2015-03-02 10:27:35 -0500 asked a question Slam Raspberry Pi 2 *

The raspberry pi 2 is a much more powerful version of raspberry pi. I've installed ROS hydro on it because I had problems with ROS Indigo.

First of all its a quadcopter with a seperate microcontroller for stabilization and position hold.

I have an 2D RpLidar, down facing optical flow sensor, and a down facing sonar for altitude as well as an IMU.

I've seen many slam libraries, but only one slam example was similar to my problem.

I was wondering what slam library I could use for 3D slam?