樹莓派 and ROS
===
https://blog.csdn.net/qq_52785580/article/details/122648288
filezilla 檔案傳輸
VNC viewer

sudo gedit ~/.bashrc
sudo gedit /etc/hostname
sudo gedit /etc/hosts

> 將ROS結構 使用圖形(graph)的方式顯示
rqt_graph

> rosnode kill [node_name]

killall -9 roscore
killall -9 rosmaster
>
2. 開啟一個新終端，開啟小烏龜
rosrun turtlesim turtlesim_node
3. 開啟一個新終端，通過鍵盤控制小烏龜，這個終端視窗必須置頂才能鍵盤控制
rosrun turtlesim turtle_teleop_key
>
> rostopic bw display bandwidth used by topic
rostopic echo print messages to screen
rostopic hz display publishing rate of topic
rostopic list print information about active topics
rostopic pub publish data to topic
rostopic type print topic type

在 Raspberry pi3 B 上使用ROS傳輸圖片 640x480x1

10hz採樣：
圖片右上 可得知影像傳輸時間大約100ms
https://i.imgur.com/CFQir9b.png
樹莓派從cap上抓影像透過ROS傳輸給PC端
整體花費時間大約300ms

15hz採樣：
會掉封包(樹莓派沒辦法cover)
整體花費時間會超過1.5s, 且隨時間增加

然後我在PC端ping 樹莓派是30~40 ms

> https://kejyuntw.gitbooks.io/ubuntu-learning-notes/content/system/system-virtual-memory.html

> sudo netstat -ltnp
> kill -9 <pid>

raspberry pi camera v2.1
===
https://blog.csdn.net/qq_52785580/article/details/122648288

rqt_image_view #选择相应的话题显示画面

hamachi
===
sudo dpkg --add-architecture armhf
sudo apt-get install libc6:armhf
sudo apt-get install libstdc++6:armhf

sudo service logmein-hamachi restart
> https://blog.xuite.net/applijack/twblog/140147547-EZGO9-Hamachi+2.1.0.17+%E7%B0%A1%E6%98%93%E5%AE%89%E8%A3%9D%E6%95%99%E5%AD%B8
https://home.gamer.com.tw/bookmarkDetail.php?sn=3301866&owner=blankuser
https://medium.com/@KyleARector/logmein-hamachi-on-raspberry-pi-ad2ba3619f3a

Kalibr相机校正工具安装与使用笔记
===
https://zhaoxuhui.top/blog/2020/09/09/kalibr-installation-and-use.html

https://blog.csdn.net/u011178262/article/details/83316968