ROS Serial library for Mbed platforms for ROS Melodic Morenia. Check http://wiki.ros.org/rosserial_mbed/ for more information.
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(); } }
ros/msg.h
- Committer:
- Gary Servin
- Date:
- 2019-11-08
- Revision:
- 0:04ac6be8229a
File content as of revision 0:04ac6be8229a:
/* * Software License Agreement (BSD License) * * Copyright (c) 2011, Willow Garage, Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following * disclaimer in the documentation and/or other materials provided * with the distribution. * * Neither the name of Willow Garage, Inc. nor the names of its * contributors may be used to endorse or promote prducts derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #ifndef _ROS_MSG_H_ #define _ROS_MSG_H_ #include <stdint.h> #include <stddef.h> namespace ros { /* Base Message Type */ class Msg { public: virtual int serialize(unsigned char *outbuffer) const = 0; virtual int deserialize(unsigned char *data) = 0; virtual const char * getType() = 0; virtual const char * getMD5() = 0; /** * @brief This tricky function handles promoting a 32bit float to a 64bit * double, so that AVR can publish messages containing float64 * fields, despite AVV having no native support for double. * * @param[out] outbuffer pointer for buffer to serialize to. * @param[in] f value to serialize. * * @return number of bytes to advance the buffer pointer. * */ static int serializeAvrFloat64(unsigned char* outbuffer, const float f) { const int32_t* val = (int32_t*) &f; int32_t exp = ((*val >> 23) & 255); if (exp != 0) { exp += 1023 - 127; } int32_t sig = *val; *(outbuffer++) = 0; *(outbuffer++) = 0; *(outbuffer++) = 0; *(outbuffer++) = (sig << 5) & 0xff; *(outbuffer++) = (sig >> 3) & 0xff; *(outbuffer++) = (sig >> 11) & 0xff; *(outbuffer++) = ((exp << 4) & 0xF0) | ((sig >> 19) & 0x0F); *(outbuffer++) = (exp >> 4) & 0x7F; // Mark negative bit as necessary. if (f < 0) { *(outbuffer - 1) |= 0x80; } return 8; } /** * @brief This tricky function handles demoting a 64bit double to a * 32bit float, so that AVR can understand messages containing * float64 fields, despite AVR having no native support for double. * * @param[in] inbuffer pointer for buffer to deserialize from. * @param[out] f pointer to place the deserialized value in. * * @return number of bytes to advance the buffer pointer. */ static int deserializeAvrFloat64(const unsigned char* inbuffer, float* f) { uint32_t* val = (uint32_t*)f; inbuffer += 3; // Copy truncated mantissa. *val = ((uint32_t)(*(inbuffer++)) >> 5 & 0x07); *val |= ((uint32_t)(*(inbuffer++)) & 0xff) << 3; *val |= ((uint32_t)(*(inbuffer++)) & 0xff) << 11; *val |= ((uint32_t)(*inbuffer) & 0x0f) << 19; // Copy truncated exponent. uint32_t exp = ((uint32_t)(*(inbuffer++)) & 0xf0) >> 4; exp |= ((uint32_t)(*inbuffer) & 0x7f) << 4; if (exp != 0) { *val |= ((exp) - 1023 + 127) << 23; } // Copy negative sign. *val |= ((uint32_t)(*(inbuffer++)) & 0x80) << 24; return 8; } // Copy data from variable into a byte array template<typename A, typename V> static void varToArr(A arr, const V var) { for (size_t i = 0; i < sizeof(V); i++) arr[i] = (var >> (8 * i)); } // Copy data from a byte array into variable template<typename V, typename A> static void arrToVar(V& var, const A arr) { var = 0; for (size_t i = 0; i < sizeof(V); i++) var |= (arr[i] << (8 * i)); } }; } // namespace ros #endif