Fix topic names

readme.md

@@ -5,29 +5,39 @@ This package is tested with Raspberry Pi 4 Model B with Ubuntu 20.04 LTS and fox
 
 ## Install
 
-1. Install pigpio following official instruction
+1. Install pigpio following [official instruction](https://abyz.me.uk/rpi/pigpio/download.html)
 1. Download this repository in `<your ros2 workspace>/src`
-1. build this package
+1. build this package with `colcon build --packages-select ros2_pigpio`
 
 
+## Preparing
+
+```bash
+sudo pigpiod # run pigpio daemon
+cd <ros2_ws> # go to your ros2 workspace
+source install/local_setup.bash # install local setup
+```
+
 ## Read Input Pin
 
-To read inputted signal on GPIO-21 (PULL_UP), run a following command. 
+To read inputted signal on GPIO-21 (PULL_UP), run the following command. 
+A publisher will send read value of the pin.
 ```
 ros2 run ros2_pigpio gpio_reader --ros-args --param pin:=21
 ```
 
-You can set a input pin as pull-down as below, 
+You can set a input pin in pull-down with the below, 
 ```
 ros2 run ros2_pigpio gpio_reader --ros-args --param pin:=21 --param is_pull_up:=false
 ```
 
 ## Write Output Pin
-To write signal with GPIO-21, run a following command. 
+To write signal with GPIO-21, run a following command. A subscriber will wait for your inputs.
 ```
 ros2 run ros2_pigpio gpio_writer --ros-args --param pin:=21 
 ```
 
+When you submit a value to the subscriber, it write the signal on the pin. 
 Write high signal:
 ```
 ros2 topic pub --once gpio_output_21 std_msgs/msg/Bool '{data: true}'

src/gpio_pwm_writer.cpp

@@ -40,7 +40,7 @@ class PWMWriter : public rclcpp::Node
     {
       set_mode(pi_, pin_, PI_OUTPUT);
       std::stringstream ss;
-      ss << "gpio_pwm_" << std::setw(2) << pin_;
+      ss << "gpio_pwm_" << std::setfill('0') << std::right << std::setw(2) << pin_;
       subscription_ = this->create_subscription<std_msgs::msg::Int16>(
           ss.str(), 10, std::bind(&PWMWriter::topic_callback, this, _1));
     }

src/gpio_reader.cpp

@@ -68,7 +68,7 @@ class DigitalReader : public rclcpp::Node
         set_pull_up_down(pi_, pin_, PI_PUD_OFF);
       }
       std::stringstream ss;
-      ss << "gpio_input_" << std::setw(2) << pin_;
+      ss << "gpio_input_" << std::setfill('0') << std::right << std::setw(2) << pin_;
       publisher_ = this->create_publisher<std_msgs::msg::Bool>(ss.str(), 10);
       timer_ = this->create_wall_timer(
           500ms, std::bind(&DigitalReader::timer_callback, this));

src/gpio_writer.cpp

@@ -40,7 +40,7 @@ class DigitalWriter : public rclcpp::Node
     {
       set_mode(pi_, pin_, PI_OUTPUT);
       std::stringstream ss;
-      ss << "gpio_output_" << std::setw(2) << pin_;
+      ss << "gpio_output_" << std::setfill('0') << std::right << std::setw(2) << pin_;
       subscription_ = this->create_subscription<std_msgs::msg::Bool>(
           ss.str(), 10, std::bind(&DigitalWriter::topic_callback, this, _1));
     }