Gary Servin / ros_lib_indigo

ROS Serial library for Mbed platforms for ROS Indigo Igloo. Check http://wiki.ros.org/rosserial_mbed/ for more information

Dependencies:   BufferedSerial

Dependents:   rosserial_mbed_hello_world_publisher rtos_base_control rosserial_mbed_F64MA ROS-RTOS ... more

ROSSerial_mbed for Indigo Distribution

The Robot Operating System (ROS) is a flexible framework for writing robot software. It is a collection of tools, libraries, and conventions that aim to simplify the task of creating complex and robust robot behavior across a wide variety of robotic platforms.

The rosserial_mbed package allows to write ROS nodes on any mbed enabled devices and have them connected to a running ROS system on your computer using the serial port.

Hello World (example publisher)

Running the Code

Now, launch the roscore in a new terminal window:

Next, run the rosserial client application that forwards your MBED messages to the rest of ROS. Make sure to use the correct serial port:

Finally, watch the greetings come in from your MBED by launching a new terminal window and entering :

See Also

• rosserial_mbed wiki
• rosserial_mbed tutorials

More examples

/*
 * rosserial Subscriber Example
 * Blinks an LED on callback
 */
#include "mbed.h"
#include <ros.h>
#include <std_msgs/Empty.h>

ros::NodeHandle nh;
DigitalOut myled(LED1);

void messageCb(const std_msgs::Empty& toggle_msg){
    myled = !myled;   // blink the led
}

ros::Subscriber<std_msgs::Empty> sub("toggle_led", &messageCb);

int main() {
    nh.initNode();
    nh.subscribe(sub);

    while (1) {
        nh.spinOnce();
        wait_ms(1);
    }
}

/*
 * Button Example for Rosserial
 */

#include "mbed.h"
#include <ros.h>
#include <std_msgs/Bool.h>

PinName button = p20;

ros::NodeHandle nh;

std_msgs::Bool pushed_msg;
ros::Publisher pub_button("pushed", &pushed_msg);

DigitalIn button_pin(button);
DigitalOut led_pin(LED1);

bool last_reading;
long last_debounce_time=0;
long debounce_delay=50;
bool published = true;

Timer t;
int main() {
    t.start();
    nh.initNode();
    nh.advertise(pub_button);

    //Enable the pullup resistor on the button
    button_pin.mode(PullUp);

    //The button is a normally button
    last_reading = ! button_pin;

    while (1) {
        bool reading = ! button_pin;

        if (last_reading!= reading) {
            last_debounce_time = t.read_ms();
            published = false;
        }

        //if the button value has not changed for the debounce delay, we know its stable
        if ( !published && (t.read_ms() - last_debounce_time)  > debounce_delay) {
            led_pin = reading;
            pushed_msg.data = reading;
            pub_button.publish(&pushed_msg);
            published = true;
        }

        last_reading = reading;

        nh.spinOnce();
    }
}

/*
 * MbedHardware
 *
 *  Created on: Aug 17, 2011
 *      Author: nucho
 */

#ifndef ROS_MBED_HARDWARE_H_
#define ROS_MBED_HARDWARE_H_

#include "mbed.h"

#include "BufferedSerial.h"

class MbedHardware {
  public:
    MbedHardware(PinName tx, PinName rx, long baud = 57600)
      :iostream(tx, rx){
      baud_ = baud;
      t.start();
    }

    MbedHardware()
      :iostream(USBTX, USBRX) {
        baud_ = 57600;
        t.start();
    }

    void setBaud(long baud){
      this->baud_= baud;
    }

    int getBaud(){return baud_;}

    void init(){
        iostream.baud(baud_);
    }

    int read(){
        if (iostream.readable()) {
            return iostream.getc();
        } else {
            return -1;
        }
    };
    void write(uint8_t* data, int length) {
        for (int i=0; i<length; i++)
             iostream.putc(data[i]);
    }

    unsigned long time(){return t.read_ms();}

protected:
    BufferedSerial iostream;
    long baud_;
    Timer t;
};


#endif /* ROS_MBED_HARDWARE_H_ */