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

Dependencies:   BufferedSerial

Dependents:   rosserial_mbed_hello_world_publisher_melodic Motortest Nucleo_vr_servo_project NucleoFM ... more

ROSSerial_mbed for Melodic 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)

Import programrosserial_mbed_hello_world_publisher_melodic

rosserial_mbed Hello World example for Melodic Morenia distribution

Running the Code

Now, launch the roscore in a new terminal window:

Quote:

$ roscore

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

Quote:

$ rosrun rosserial_python serial_node.py /dev/ttyACM0

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

Quote:

$ rostopic echo chatter

See Also

More examples

Blink

/*
 * 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);
    }
}

Push

/*
 * 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();
    }
}
Committer:
Gary Servin
Date:
Fri Nov 08 14:38:09 2019 -0300
Revision:
0:04ac6be8229a
Initial commit, generated based on a clean melodic-desktop-full

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Gary Servin 0:04ac6be8229a 1 /*
Gary Servin 0:04ac6be8229a 2 * Software License Agreement (BSD License)
Gary Servin 0:04ac6be8229a 3 *
Gary Servin 0:04ac6be8229a 4 * Copyright (c) 2011, Willow Garage, Inc.
Gary Servin 0:04ac6be8229a 5 * All rights reserved.
Gary Servin 0:04ac6be8229a 6 *
Gary Servin 0:04ac6be8229a 7 * Redistribution and use in source and binary forms, with or without
Gary Servin 0:04ac6be8229a 8 * modification, are permitted provided that the following conditions
Gary Servin 0:04ac6be8229a 9 * are met:
Gary Servin 0:04ac6be8229a 10 *
Gary Servin 0:04ac6be8229a 11 * * Redistributions of source code must retain the above copyright
Gary Servin 0:04ac6be8229a 12 * notice, this list of conditions and the following disclaimer.
Gary Servin 0:04ac6be8229a 13 * * Redistributions in binary form must reproduce the above
Gary Servin 0:04ac6be8229a 14 * copyright notice, this list of conditions and the following
Gary Servin 0:04ac6be8229a 15 * disclaimer in the documentation and/or other materials provided
Gary Servin 0:04ac6be8229a 16 * with the distribution.
Gary Servin 0:04ac6be8229a 17 * * Neither the name of Willow Garage, Inc. nor the names of its
Gary Servin 0:04ac6be8229a 18 * contributors may be used to endorse or promote prducts derived
Gary Servin 0:04ac6be8229a 19 * from this software without specific prior written permission.
Gary Servin 0:04ac6be8229a 20 *
Gary Servin 0:04ac6be8229a 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
Gary Servin 0:04ac6be8229a 22 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
Gary Servin 0:04ac6be8229a 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
Gary Servin 0:04ac6be8229a 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
Gary Servin 0:04ac6be8229a 25 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
Gary Servin 0:04ac6be8229a 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
Gary Servin 0:04ac6be8229a 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
Gary Servin 0:04ac6be8229a 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
Gary Servin 0:04ac6be8229a 29 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
Gary Servin 0:04ac6be8229a 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
Gary Servin 0:04ac6be8229a 31 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
Gary Servin 0:04ac6be8229a 32 * POSSIBILITY OF SUCH DAMAGE.
Gary Servin 0:04ac6be8229a 33 */
Gary Servin 0:04ac6be8229a 34
Gary Servin 0:04ac6be8229a 35 #ifndef _ROS_MSG_H_
Gary Servin 0:04ac6be8229a 36 #define _ROS_MSG_H_
Gary Servin 0:04ac6be8229a 37
Gary Servin 0:04ac6be8229a 38 #include <stdint.h>
Gary Servin 0:04ac6be8229a 39 #include <stddef.h>
Gary Servin 0:04ac6be8229a 40
Gary Servin 0:04ac6be8229a 41 namespace ros
Gary Servin 0:04ac6be8229a 42 {
Gary Servin 0:04ac6be8229a 43
Gary Servin 0:04ac6be8229a 44 /* Base Message Type */
Gary Servin 0:04ac6be8229a 45 class Msg
Gary Servin 0:04ac6be8229a 46 {
Gary Servin 0:04ac6be8229a 47 public:
Gary Servin 0:04ac6be8229a 48 virtual int serialize(unsigned char *outbuffer) const = 0;
Gary Servin 0:04ac6be8229a 49 virtual int deserialize(unsigned char *data) = 0;
Gary Servin 0:04ac6be8229a 50 virtual const char * getType() = 0;
Gary Servin 0:04ac6be8229a 51 virtual const char * getMD5() = 0;
Gary Servin 0:04ac6be8229a 52
Gary Servin 0:04ac6be8229a 53 /**
Gary Servin 0:04ac6be8229a 54 * @brief This tricky function handles promoting a 32bit float to a 64bit
Gary Servin 0:04ac6be8229a 55 * double, so that AVR can publish messages containing float64
Gary Servin 0:04ac6be8229a 56 * fields, despite AVV having no native support for double.
Gary Servin 0:04ac6be8229a 57 *
Gary Servin 0:04ac6be8229a 58 * @param[out] outbuffer pointer for buffer to serialize to.
Gary Servin 0:04ac6be8229a 59 * @param[in] f value to serialize.
Gary Servin 0:04ac6be8229a 60 *
Gary Servin 0:04ac6be8229a 61 * @return number of bytes to advance the buffer pointer.
Gary Servin 0:04ac6be8229a 62 *
Gary Servin 0:04ac6be8229a 63 */
Gary Servin 0:04ac6be8229a 64 static int serializeAvrFloat64(unsigned char* outbuffer, const float f)
Gary Servin 0:04ac6be8229a 65 {
Gary Servin 0:04ac6be8229a 66 const int32_t* val = (int32_t*) &f;
Gary Servin 0:04ac6be8229a 67 int32_t exp = ((*val >> 23) & 255);
Gary Servin 0:04ac6be8229a 68 if (exp != 0)
Gary Servin 0:04ac6be8229a 69 {
Gary Servin 0:04ac6be8229a 70 exp += 1023 - 127;
Gary Servin 0:04ac6be8229a 71 }
Gary Servin 0:04ac6be8229a 72
Gary Servin 0:04ac6be8229a 73 int32_t sig = *val;
Gary Servin 0:04ac6be8229a 74 *(outbuffer++) = 0;
Gary Servin 0:04ac6be8229a 75 *(outbuffer++) = 0;
Gary Servin 0:04ac6be8229a 76 *(outbuffer++) = 0;
Gary Servin 0:04ac6be8229a 77 *(outbuffer++) = (sig << 5) & 0xff;
Gary Servin 0:04ac6be8229a 78 *(outbuffer++) = (sig >> 3) & 0xff;
Gary Servin 0:04ac6be8229a 79 *(outbuffer++) = (sig >> 11) & 0xff;
Gary Servin 0:04ac6be8229a 80 *(outbuffer++) = ((exp << 4) & 0xF0) | ((sig >> 19) & 0x0F);
Gary Servin 0:04ac6be8229a 81 *(outbuffer++) = (exp >> 4) & 0x7F;
Gary Servin 0:04ac6be8229a 82
Gary Servin 0:04ac6be8229a 83 // Mark negative bit as necessary.
Gary Servin 0:04ac6be8229a 84 if (f < 0)
Gary Servin 0:04ac6be8229a 85 {
Gary Servin 0:04ac6be8229a 86 *(outbuffer - 1) |= 0x80;
Gary Servin 0:04ac6be8229a 87 }
Gary Servin 0:04ac6be8229a 88
Gary Servin 0:04ac6be8229a 89 return 8;
Gary Servin 0:04ac6be8229a 90 }
Gary Servin 0:04ac6be8229a 91
Gary Servin 0:04ac6be8229a 92 /**
Gary Servin 0:04ac6be8229a 93 * @brief This tricky function handles demoting a 64bit double to a
Gary Servin 0:04ac6be8229a 94 * 32bit float, so that AVR can understand messages containing
Gary Servin 0:04ac6be8229a 95 * float64 fields, despite AVR having no native support for double.
Gary Servin 0:04ac6be8229a 96 *
Gary Servin 0:04ac6be8229a 97 * @param[in] inbuffer pointer for buffer to deserialize from.
Gary Servin 0:04ac6be8229a 98 * @param[out] f pointer to place the deserialized value in.
Gary Servin 0:04ac6be8229a 99 *
Gary Servin 0:04ac6be8229a 100 * @return number of bytes to advance the buffer pointer.
Gary Servin 0:04ac6be8229a 101 */
Gary Servin 0:04ac6be8229a 102 static int deserializeAvrFloat64(const unsigned char* inbuffer, float* f)
Gary Servin 0:04ac6be8229a 103 {
Gary Servin 0:04ac6be8229a 104 uint32_t* val = (uint32_t*)f;
Gary Servin 0:04ac6be8229a 105 inbuffer += 3;
Gary Servin 0:04ac6be8229a 106
Gary Servin 0:04ac6be8229a 107 // Copy truncated mantissa.
Gary Servin 0:04ac6be8229a 108 *val = ((uint32_t)(*(inbuffer++)) >> 5 & 0x07);
Gary Servin 0:04ac6be8229a 109 *val |= ((uint32_t)(*(inbuffer++)) & 0xff) << 3;
Gary Servin 0:04ac6be8229a 110 *val |= ((uint32_t)(*(inbuffer++)) & 0xff) << 11;
Gary Servin 0:04ac6be8229a 111 *val |= ((uint32_t)(*inbuffer) & 0x0f) << 19;
Gary Servin 0:04ac6be8229a 112
Gary Servin 0:04ac6be8229a 113 // Copy truncated exponent.
Gary Servin 0:04ac6be8229a 114 uint32_t exp = ((uint32_t)(*(inbuffer++)) & 0xf0) >> 4;
Gary Servin 0:04ac6be8229a 115 exp |= ((uint32_t)(*inbuffer) & 0x7f) << 4;
Gary Servin 0:04ac6be8229a 116 if (exp != 0)
Gary Servin 0:04ac6be8229a 117 {
Gary Servin 0:04ac6be8229a 118 *val |= ((exp) - 1023 + 127) << 23;
Gary Servin 0:04ac6be8229a 119 }
Gary Servin 0:04ac6be8229a 120
Gary Servin 0:04ac6be8229a 121 // Copy negative sign.
Gary Servin 0:04ac6be8229a 122 *val |= ((uint32_t)(*(inbuffer++)) & 0x80) << 24;
Gary Servin 0:04ac6be8229a 123
Gary Servin 0:04ac6be8229a 124 return 8;
Gary Servin 0:04ac6be8229a 125 }
Gary Servin 0:04ac6be8229a 126
Gary Servin 0:04ac6be8229a 127 // Copy data from variable into a byte array
Gary Servin 0:04ac6be8229a 128 template<typename A, typename V>
Gary Servin 0:04ac6be8229a 129 static void varToArr(A arr, const V var)
Gary Servin 0:04ac6be8229a 130 {
Gary Servin 0:04ac6be8229a 131 for (size_t i = 0; i < sizeof(V); i++)
Gary Servin 0:04ac6be8229a 132 arr[i] = (var >> (8 * i));
Gary Servin 0:04ac6be8229a 133 }
Gary Servin 0:04ac6be8229a 134
Gary Servin 0:04ac6be8229a 135 // Copy data from a byte array into variable
Gary Servin 0:04ac6be8229a 136 template<typename V, typename A>
Gary Servin 0:04ac6be8229a 137 static void arrToVar(V& var, const A arr)
Gary Servin 0:04ac6be8229a 138 {
Gary Servin 0:04ac6be8229a 139 var = 0;
Gary Servin 0:04ac6be8229a 140 for (size_t i = 0; i < sizeof(V); i++)
Gary Servin 0:04ac6be8229a 141 var |= (arr[i] << (8 * i));
Gary Servin 0:04ac6be8229a 142 }
Gary Servin 0:04ac6be8229a 143
Gary Servin 0:04ac6be8229a 144 };
Gary Servin 0:04ac6be8229a 145
Gary Servin 0:04ac6be8229a 146 } // namespace ros
Gary Servin 0:04ac6be8229a 147
Gary Servin 0:04ac6be8229a 148 #endif