Button_example.cpp

00001 //#define COMPILE_BUTTON_EXAMPLE_CODE_ROSSERIAL
00002 #ifdef  COMPILE_BUTTON_EXAMPLE_CODE_ROSSERIAL
00003 
00004 /*
00005  * Button Example for Rosserial
00006  */
00007 
00008 #include "mbed.h"
00009 #include <ros.h>
00010 #include <std_msgs/Bool.h>
00011 
00012 
00013 ros::NodeHandle nh;
00014 
00015 std_msgs::Bool pushed_msg;
00016 ros::Publisher pub_button("pushed", &pushed_msg);
00017 
00018 DigitalIn button_pin(p8);
00019 DigitalOut led_pin(LED1);
00020 
00021 bool last_reading;
00022 long last_debounce_time=0;
00023 long debounce_delay=50;
00024 bool published = true;
00025 
00026 Timer t;
00027 int main() {
00028     t.start();
00029     nh.initNode();
00030     nh.advertise(pub_button);
00031 
00032     //Enable the pullup resistor on the button
00033     button_pin.mode(PullUp);
00034 
00035     //The button is a normally button
00036     last_reading = ! button_pin;
00037 
00038     while (1) {
00039         bool reading = ! button_pin;
00040 
00041         if (last_reading!= reading) {
00042             last_debounce_time = t.read_ms();
00043             published = false;
00044         }
00045 
00046         //if the button value has not changed for the debounce delay, we know its stable
00047         if ( !published && (t.read_ms() - last_debounce_time)  > debounce_delay) {
00048             led_pin = reading;
00049             pushed_msg.data = reading;
00050             pub_button.publish(&pushed_msg);
00051             published = true;
00052         }
00053 
00054         last_reading = reading;
00055 
00056         nh.spinOnce();
00057     }
00058 }
00059 #endif