rviz : warning message no map received

edit

Hi

I'm trying to visualize a map using 3 ultrasonic sensor and arduino mega 2560. I developed my own node to generate LaserScan from 3 sonar range. Algorithm using for mapping is gmapping.

rang_to_laserscan.cpp :

#include "ros/ros.h"
#include "sensor_msgs/Range.h"
#include "sensor_msgs/LaserScan.h"

float data[3];

void u1Callback(const sensor_msgs::Range::ConstPtr& r1)
{
  data[0]=r1->range;
}

void u2Callback(const sensor_msgs::Range::ConstPtr& r2)
{
  data[1]=r2->range;
}

void u3Callback(const sensor_msgs::Range::ConstPtr& r3)
{
  data[2]=r3->range;
}

int main(int argc, char** argv){
   ros::init(argc, argv, "rang_to_laserscan");
   ros::NodeHandle n;

   ros::Subscriber sub_u1 = n.subscribe("/ultrasound1", 1000, u1Callback);
   ros::Subscriber sub_u2 = n.subscribe("/ultrasound2", 1000, u2Callback);
   ros::Subscriber sub_u3 = n.subscribe("/ultrasound3", 1000, u3Callback);

   ros::Publisher pub1 = n.advertise<sensor_msgs::LaserScan>("/scan1", 50);

   int num_readings = 3;
   float laser_frequency = 40;

   ros::Rate loop_rate(10);

   while (ros::ok())
   {
      ros::Time scan_time = ros::Time::now();

      sensor_msgs::LaserScan scan;
      scan.header.stamp = scan_time;
      scan.header.frame_id = "range_to_laser_frame";
      scan.angle_min = -0.785398;
      scan.angle_max = 0.785398;
      scan.angle_increment = 1.570796 / num_readings;
      scan.time_increment = (1 / laser_frequency) / (num_readings);
      scan.range_min = 0.02;
      scan.range_max = 4.0;     

      scan.ranges.resize(num_readings);

      for(int i=0;i<num_readings;i++){
           scan.ranges[i]  = data[i];
      }   

      pub1.publish(scan);

      ros::spinOnce();

      loop_rate.sleep();
   }

   return 0;
}

arduino code :

#include <ros.h>
#include <ros/time.h>
#include <sensor_msgs/Range.h>

long duration;float d;int i=0;
int T[]={23,25,27,29,31,33,35,37,39,41}; 
int E[]={22,24,26,28,30,32,34,36,38,40}; 

ros::NodeHandle  nh;

sensor_msgs::Range range_msg;
ros::Publisher pub_range1("/ultrasound1", &range_msg);
ros::Publisher pub_range2("/ultrasound2", &range_msg);
ros::Publisher pub_range3("/ultrasound3", &range_msg);
/*ros::Publisher pub_range4("/ultrasound4", &range_msg);
ros::Publisher pub_range5("/ultrasound5", &range_msg);
ros::Publisher pub_range6("/ultrasound6", &range_msg);
ros::Publisher pub_range7("/ultrasound7", &range_msg);
ros::Publisher pub_range8("/ultrasound8", &range_msg);
ros::Publisher pub_range9("/ultrasound9", &range_msg);
ros::Publisher pub_range10("/ultrasound10", &range_msg);*/

char frameid[] = "/ultrasound";

float getRange(int T,int E)
{
  digitalWrite(T,HIGH);
  delayMicroseconds(10);
  digitalWrite(T,LOW);
  duration=pulseIn(E,HIGH);
  d=duration/58;
  delayMicroseconds(5);
  return d/100;
}

void setup()
{
  nh.initNode();
  nh.advertise(pub_range1);
  nh.advertise(pub_range2);
  nh.advertise(pub_range3);
  /*nh.advertise(pub_range4);
  nh.advertise(pub_range5);
  nh.advertise(pub_range6);
  nh.advertise(pub_range7);
  nh.advertise(pub_range8);
  nh.advertise(pub_range9);
  nh.advertise(pub_range10);*/

  range_msg.radiation_type = sensor_msgs::Range::ULTRASOUND;
  range_msg.header.frame_id =  frameid;
  range_msg.field_of_view = 1.570796;
  range_msg.min_range = 0.02;
  range_msg.max_range = 4.0;

  for(i=0;i<3;i++){
    pinMode(T[i], OUTPUT); 
    digitalWrite(T[i], LOW); 
    pinMode(E[i], INPUT); 
  }
}

long range_time;

void loop()
{
  if ( millis() >= range_time ){

    range_msg.range = getRange(T[0],E[0]);
    range_msg.header.stamp = nh.now();
    pub_range1.publish(&range_msg);

    range_msg.range = getRange(T[1],E[1]);
    range_msg.header.stamp = nh.now();
    pub_range2.publish(&range_msg);

    range_msg.range = getRange(T[2],E[2]);
    range_msg.header.stamp = nh.now();
    pub_range3.publish(&range_msg);

    /*range_msg.range = getRange(T[3],E[3]);
    range_msg.header.stamp = nh.now();
    pub_range4.publish(&range_msg);

    range_msg.range = getRange(T[4],E[4]);
    range_msg.header.stamp = nh.now();
    pub_range5.publish(&range_msg);

    range_msg.range = getRange(T ...