[Tips] 好用的抓圖軟體@Ubuntu

byzanz 看起來更好用, 直接輸出成 gif, 可以說是長得放 youtube, 短的就用 gif

reference: https://askubuntu.com/questions/107726/how-to-create-animated-gif-images-of-a-screencast

[OpenCV] learnopencv

source: https://github.com/spmallick/learnopencv

[RPi] Video Straming using RTSP

使用 RTSP 做串流會延遲得很厲害, 除了可以調整 VLC 參數以外, 這篇看起來很厲害, 不過還是沒成功, 可能是我 Ubuntu 太舊了 QQ

[Camera] 多個程序存取 V4L2 Camera

這篇寫得很多方法, 但是都不成功 :(

另外紀錄一下, 這幾篇
* http://www.sistemasembarcados.org/2016/04/05/orange-pi-camera-with-v4l2loopback-vidcopy/
 

[RPi] 從外部連回 Pi

如果沒辦法控制外部的 Router 或是 Firewall, 大概有兩種方法, 一個是使用外部的 reverse SSH tunel, 例如這篇介紹的

另外一種就是要使用外部的服務, 例如 dataplicity 但通常需要搭配 ddns 服務

或者直接使用 weaved, 可開啟 SSH 或是 HTTP 等, 使用方法可看官網教學, 還有 dexterindustries 這篇(記得要 connect 以後會發配一個 domain name)

[Tips] 使用 DynDNS 連回自己的電腦

1. 先使用 10 minute mail 註冊一個 noip 帳號, 要記得帳號密碼

2. 然後下載原始碼後編譯
$ cd ~
$ wget http://www.no-ip.com/client/linux/noip-duc-linux.tar.gz
$ tar xf noip-duc-linux.tar.gz
$ cd noip-2.1.9-1/
$ sudo make install

接著就會問你問題, 參考如下
if [ ! -d /usr/local/bin ]; then mkdir -p /usr/local/bin;fi
if [ ! -d /usr/local/etc ]; then mkdir -p /usr/local/etc;fi
cp noip2 /usr/local/bin/noip2
/usr/local/bin/noip2 -C -c /tmp/no-ip2.conf

Auto configuration for Linux client of no-ip.com.

Multiple network devices have been detected.

Please select the Internet interface from this list.

By typing the number associated with it.
0    eth0
1    eth0
2    wlan0
3    eth1
3
Please enter the login/email string for no-ip.com  foo@bar.net
Please enter the password for user 'foo@bar.net'  *******

Only one host [foo.ddns.net] is registered to this account.
It will be used.
Please enter an update interval:[30] 
Do you wish to run something at successful update?[N] (y/N)  y
Please enter the script/program name  foo

New configuration file '/tmp/no-ip2.conf' created.

mv /tmp/no-ip2.conf /usr/local/etc/no-ip2.conf

設定檔路徑為 /usr/local/etc/no-ip2.conf

3. 啟動 client, 會重新註冊 IP
sudo /usr/local/bin/noip2

如果沒問題的話, 應該就可以從外部看到 foo.ddns.net 的結果了


reference:
* http://www.darwinbiler.com/dynamic-dns-using-raspberry-pi/
* http://www.awesomeweirdness.com/projects-diy/raspberrypi/setup-noip-client-raspberry-pi/

這篇寫得不錯, 應該會有兩個東西要設定, 另一個是把 DUC 當 service 跑起來
DUC Client 和 No-IP DUC Client service
* http://sizious.com/2017/04/30/how-to-properly-install-no-ip-dynamic-update-client-duc-under-raspbian/

備註; 如果在防火牆後面可以使用 dataplicity 這服務 

[RPi] SSH Hangs After Authentication on Raspberry Pi 3

今天遇到怪事, 在 Windows 上用 putty 連線到 Pi 3, 進入到登入畫面後就停住了, 看了這篇照著修改有改善

簡單說, 修改這兩個檔案
/etc/ssh/ssh_config
/etc/ssh/sshd_config

新增一行在檔案最後面, 再重啟 sshd 服務即可
IPQoS 0x00

reference: https://expresshosting.net/ssh-hanging-authentication/

[Python] numpy操作

在處理影像時會用到 numpy 的 ndarray, python numpy笔记 寫得蠻不錯得

[Tips] 如何從google driver直接下載檔案

參考這篇：https://stackoverflow.com/questions/37453841/download-a-file-from-google-drive-using-wget

這兩篇好像不成功
https://stackoverflow.com/questions/25010369/wget-curl-large-file-from-google-drive
https://stackoverflow.com/questions/20665881/direct-download-from-google-drive-using-google-drive-api

[RPi] advmame性能調校

修改 ~/.advance/advmame.rc 裡面 video 使用 SDL 會有明顯改善

device_video sdl
device_video_output fullscreen
256x224/display_mode sdl_256x240

reference: http://www.arcadeinfo.de/archive/index.php/t-2917.html

[Tips] 錄桌面 & 影片剪輯軟體 @ Ubuntu

最近想要開始搞錄影, 會需要影片編輯, 還需要錄製桌面

錄桌面用 gtk-recordmydesktop 應該是最容易入門的, 只是還要轉檔

轉檔可以參考 Tsung 這篇：
https://blog.longwin.com.tw/2009/04/linux-record-recordmydesktop-2009/

$ mencoder out.ogv -nosound -ovc lavc -o out.avi

要有聲音的話需要安裝套件
$ sudo apt-get install flac lame
$ mencoder out.ogv -oac mp3lame -ovc lavc -o out.avi

[RPi] Joy Bonnet

今天在測試 Joy Bonnet, 不過好像上鍵壞掉, 只有下鍵可以用, 所以要稍微改一下程式

主要就是在判斷的部份要改成這樣

  if (x != 1) and not analog_states[1]:
    analog_states[1] = True
    handle_button(1001)      # send DOWN press
  if (x == 1) and analog_states[1]:
    analog_states[1] = False
    handle_button(1001)      # send DOWN release



補一下 RetroPie 的使用
https://gameroomsolutions.com/raspberry-pi-3-retropie-setup-easy-guide/
https://github.com/retropie/retropie-setup/wiki/First-Installation
sudo ~/RetroPie-Setup/retropie_setup.sh

[Python] ASCII to Binary

https://stackoverflow.com/questions/18367007/python-how-to-write-to-a-binary-file
https://stackoverflow.com/questions/25168616/writing-binary-data-to-a-file-in-python
https://stackoverflow.com/questions/34687516/how-to-read-binary-files-as-hex-in-python
* https://stackoverflow.com/questions/7396849/convert-binary-to-ascii-and-vice-versa

[OpenCV] OCR

sudo apt-get install tesseract-ocr
sudo pip install pytesseract

http://vmtram.blogspot.tw/2017/05/recognize-text-from-image-with-python.html
https://zhuanlan.zhihu.com/p/20844354
http://www.cnblogs.com/zhongtang/p/5560361.html

[RPi] GY-801

馬上會用到, 筆記一下, 要修改 import 和 i2c address

https://github.com/peterjc/longsight/blob/master/gy80.py
https://github.com/bitify/raspi/tree/master/i2c-sensors/bitify/python/sensors
https://github.com/bitify/raspi/tree/master/i2c-sensors/bitify/python/utils

http://astrobeano.blogspot.tw/2014/01/gy-80-orientation-sensor-on-raspberry-pi.html


不過有些數值好像還沒讀到？

Gyroscope/Accl/Comp q (nan, nan, nan, nan), yaw nan, pitch nan, roll nan (degrees)
Gyro-only quaternion  (nan, nan, nan, nan), yaw nan, pitch nan, roll nan (degrees)
Accel/Comp quaternion (0.03, 0.16, 0.99, 0.00), yaw 161.5, pitch 3.54, roll 179.1 (degrees)

[Linux] X11 Forwarding vs. VNC

原來我一直誤會了!!
https://arstechnica.com/civis/viewtopic.php?t=1155637

[RPi] 安裝 OpenCV 3.1

都差不多, 原來只是 SD 卡空間滿了所以一直失敗 QQ

https://robocoderhan.github.io/2016/12/13/Raspberry%20Pi%203%20+%20Raspbian%20Jessie%20+%20OpenCV%203/

[RPi] Flir Lepton

GetLab
https://groupgets.com/manufacturers/getlab

FLiR Dev Kit
https://www.sparkfun.com/products/13233

FLIR Lepton Hookup Guide
https://learn.sparkfun.com/tutorials/flir-lepton-hookup-guide

How to install FLIR Lepton Thermal Camera and applications on Raspberry Pi
http://www.appropedia.org/How_to_install_FLIR_Lepton_Thermal_Camera_and_applications_on_Raspberry_Pi

Lepton
http://www.pureengineering.com/projects/lepton

Flir Lepton Thermal Imaging Sensor + Gameduino 2
http://www.theresistornetwork.com/2014/11/flir-lepton-thermal-imaging-sensor.html

Pylepton Overlay Guide 2.0 for Raspbian Pixel
https://lepton.flir.com/forums/topic/pylepton-overlay-guide-2-0-for-raspbian-pixel/

[RPi] 使用Pi 3序列埠

Raspbian Jessie 的 GPIO 串口配置

http://harttle.com/2017/01/14/raspberrypi-uart.html

有空把文章完成吧

[RPi] How to speed up X11 forwarding in SSH

還沒有明顯的差距, 但先紀錄一下幾個方法或是方向應該是有用的

1. 超頻
force_turbo=1

2. 關掉 X-Server

3. 用比較簡單的 cipher
ssh -X -c arcfour pi@192.168.2.2

需要先安裝 libgcrypt20-dev
並且修改 /etc/ssh/sshd_config
ciphers         arcfour,blowfish-cbc

4. 壓縮(或是不壓縮) ==> 眾說紛紜
不過實際測試, 壓縮比較悲劇


參考資料:
* http://xmodulo.com/how-to-speed-up-x11-forwarding-in-ssh.html
* https://serverfault.com/questions/116875/how-can-i-disable-encryption-on-openssh
* https://www.devolve.net/blog/2014/03/27/raspberry-pi-ssh-cipher-speed/