Help with Arduino ROS Communication

Projects General Guidance
1

Hi, I'm abit frustrated using rosserial at the moment. my code below
Generally works fine, when i establish connection with ROS i am able to view my encoder readings from the first motor aswell. The moment i publish speed data to any of the topics the arduino node is subscribed to, the sensor readings turn to 0 as though being canceled out. Please any help will be much appreciated.

#include <Arduino.h>
#include <ros.h>
#include <std_msgs/UInt16.h>
#include <stdio.h> 
#include <stdlib.h>
#include "speedmeter.h"
#include "motor.h"
#include "brake.h"

#define roboclawRxPin1 9
#define roboclawTxPin1 8
#define roboclawRxPin2 11
#define roboclawTxPin2 10

ros::NodeHandle nh;

std_msgs::UInt16 speed_msg1;
//----------------------------------Publish Encoder readings-------------------
ros::Publisher pb_speed1("pb_speed1", &speed_msg1);
//----------------------------------Initialize motor and encoder values------------------
Motor *myMotor1;
Motor *myMotor2;
Encoder *myEncoder1;
Encoder *myEncoder2;

//----------------------------------Subscriber call back functions for R1 Speed---------------
void speedCallback1(const std_msgs::UInt16& cmd_msg) {
    myMotor1->MotorSpeed(cmd_msg.data);
}

//----------------------------------Subscriber callback functions for R2 Speed-------------
void speedCallback2(const std_msgs::UInt16& cmd_msg){
  myMotor2->MotorSpeed(cmd_msg.data);
}

//----------------------------------Create subscription instance for ROS-Subscriber-----------------
ros::Subscriber<std_msgs::UInt16> sub_speed1("pub_speed1", speedCallback1);
ros::Subscriber<std_msgs::UInt16> sub_speed2("pub_speed2", speedCallback2);

//---------------------------------Initialize ROS,motor, and encoders---------------
void setup() {
  nh.getHardware()->setBaud(115200);
  nh.initNode();
  nh.advertise(pb_speed1);

//------------------------Create new motor object for controlling rollers1&2--------------
  myMotor1 = new Motor(roboclawRxPin1, roboclawTxPin1);
  myMotor1->MotorSpeed(10);
  myMotor2 = new Motor(roboclawRxPin2, roboclawTxPin2);
  myMotor2->MotorSpeed(10);

//------------------------Subscribe to published speeds from ROS---------------
  
  nh.subscribe(sub_speed1);
  nh.subscribe(sub_speed2);

//-----------------------Creates a new encoder object for interfacing with the motor------------------------

  myEncoder1 = new Encoder(roboclawRxPin1, roboclawTxPin1);
}

//------------------------------Reads and publishes encoder value ----------------------------
void loop() {

//------------------------------Reads the encoder value---------------------------
  int speed1Value = myEncoder1->readSpeed();
  Serial.print("Encoder1: ");
  Serial.println(speed1Value);
//-------------------------------Assign encoder vvalue to message -----------------------------
  speed_msg1.data = speed1Value;
  Serial.println(speed1Value);
//-------------------------------Publish message and handle ROS communication ------------------------------
  pb_speed1.publish(&speed_msg1);
  
  nh.spinOnce();
  delay(100);
}

and the ROS topic publishing.

rostopic pub /pub_speed1 std_msgs/UInt16 'data: 20'
2

Read the specs for the ROS. There are for sure rules for the tasks it is made to handle. Somehow Serial.print looks like violating the rules.

3

Is ROS Runner On Ship or is ROS a Robot Operating System or ???. I assume it is an operating system but I Had to go through stuff to figure that one out.

4

yes robot operating system

5

Using a call of the delay() function isn´t very tricky?

6

hi, even without the serial print there it still carries on the same way. i only had the serial prints in there to check if i could view the data from the encoder on the serial monitor of the arduino first, which it does. poblem comes when i move over to ROS.

7

Okey. Still, read the ROS specification about the rules for the tasks it administrates.
Is there memory enough for the ROS and the tasks?