ROS Serial library for Mbed platforms for ROS Indigo Igloo. Check http://wiki.ros.org/rosserial_mbed/ for more information
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)
Import programrosserial_mbed_hello_world_publisher
rosserial_mbed Hello World
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(); } }
Diff: ros/msg.h
- Revision:
- 0:fd24f7ca9688
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/ros/msg.h Thu Mar 31 14:22:59 2016 +0000 @@ -0,0 +1,129 @@ +/* + * 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> + +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; + } + +}; + +} // namespace ros + +#endif