[RPi] 趣事

剛剛在找 VideoCore 相關資料, 找到這篇, 是快要吵起來了嗎？
https://www.raspberrypi.org/forums/viewtopic.php?t=176197&p=1145622

這篇也有說了一下 ISP 的過程
https://www.raspberrypi.org/forums/viewtopic.php?t=117399&p=798444

[敗家] PIC 燒錄器

下次買一下吧
http://extremeelectronics.co.in/eXtremeBurnerPIC/docs/user_guide_pic16.htm

[Camera] Success Story of the Open-Source Camera Stack: The Nokia N9 Case

找時間k一下吧

http://free-electrons.com/pub/video/2011/elce/elce-2011-pinchart-camera-stack-nokia-n9-450p.webm

[OpenCV] OpenCV Python Neural Network Autonomous RC Car

https://zhengludwig.wordpress.com/projects/self-driving-rc-car/

[RPi] Tools and information for the Broadcom VideoCore IV (RaspberryPi)

資料有點舊, 不知道還可不可以用？
https://github.com/hermanhermitage/videocoreiv

[RPi] E3372

應該是隨插即用, 用法和 E1820 不一樣

http://www.gnuton.org/blog/2015/07/huawei-e3372/
http://nvdcstuff.blogspot.tw/2015/04/huawei-e3372-in-linux-raspberry-pi.html
https://blog.unixweb.de/usb-stick-lte-telekom-magenta-eins-huawei-e398-modem-raspberry-pi/
https://marmottecureuil.wordpress.com/2016/11/26/huawei-e3372-on-a-raspberry-pi/

加碼變成 router
http://www.g7smy.co.uk/2014/08/raspberry-pi-as-a-3g4g-router/

[RPi] Common errors using the Raspberry Pi camera module

每次都忘記, 要回來看這篇才行, 還有記得要加 rawCapture.truncate(0) 才行

http://www.pyimagesearch.com/2016/08/29/common-errors-using-the-raspberry-pi-camera-module/

[Python] 執行外部程式

這篇整理了很多
https://pymotw.com/2/subprocess/

[Tips] Microsoft Facial Recognition

https://gigaom.com/2017/04/10/discover-your-customers-deepest-feelings-using-microsoft-facial-recognition/

[RPi] SDR

Software Define Radio(SDR)

本來想要用 gqrx, 可是一直沒成功
http://gqrx.dk/download/gqrx-sdr-for-the-raspberry-pi
https://danielpocock.com/quickstart-sdr-ham-radio-gqrx-gnu-radio

後來還是使用 adafruit 的 FreqShow, 可以參考這篇
https://learn.adafruit.com/freq-show-raspberry-pi-rtl-sdr-scanner

使用 LoRa microchip 2483, 一個當 sender, 一個當 gateway, 參數如下
bw 500
sf sf12
cr 4/5
freq 868100000

sender 發送圖

gateway 接收圖




下一步就是要分析訊號強弱與傳輸距離等了
http://diydrones.com/m/blogpost?id=705844%3ABlogPost%3A2165825



後記：
SDL 要能支援 touch, 要裝舊版的
https://learn.adafruit.com/adafruit-pitft-28-inch-resistive-touchscreen-display-raspberry-pi/pitft-pygame-tips#ensure-you-are-running-sdl-1-dot-2

透過 x11vnc 看結果, 要把 freqshow.py 這幾行註解掉
        #os.putenv('SDL_VIDEODRIVER', 'fbcon')
        #os.putenv('SDL_FBDEV'      , '/dev/fb1')
        #os.putenv('SDL_MOUSEDRV'   , 'TSLIB')
        #os.putenv('SDL_MOUSEDEV'   , '/dev/input/touchscreen')

滑鼠也要顯示才行
       #pygame.mouse.set_visible(False)
       pygame.mouse.set_visible(True)

[RPi] root 可以 ssh 登入

1. 要先更新 root 密碼
$ sudo passwd root

2. 要讓 root 可以從 ssh 登入

• Login, and edit this file: sudo nano /etc/ssh/sshd_config
• Find this line: PermitRootLogin without-password
• Edit: PermitRootLogin yes

3. 重新啟動 sshd
$ sudo systemctl restart ssh.service 


參考:
http://raspberrypi.stackexchange.com/questions/48056/login-as-root-not-possible

[Python] 繪圖

如果是要畫得快, 建議是直接用 pyqtgraph, 不要用 matplotlib, 參考這篇

但如果要用 matplotlib 還是想畫得快, 可以參考這兩篇的效能調校方式
* http://stackoverflow.com/questions/8955869/why-is-plotting-with-matplotlib-so-slow
* http://bastibe.de/2013-05-30-speeding-up-matplotlib.html

[RPi] pulse sensor

都是參考 Arduino 範例改寫的
* http://udayankumar.com/2016/05/17/heart-beat-raspberry/
* https://github.com/tutRPi/Raspberry-Pi-Heartbeat-Pulse-Sensor

[Python] pyqtgraph 超基本繪圖

這要先會動才行

from pyqtgraph.Qt import QtGui, QtCore
import pyqtgraph as pg
import numpy as np

data = np.random.normal(size=1000)
#print data
pg.plot(data)   # data can be a list of values or a numpy array

if __name__ == '__main__':
    import sys

    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()

更多參考資訊
* http://www.pyqtgraph.org/documentation/how_to_use.html
* https://wiki.qt.io/PySide

[Python] pyqtgraph 重新繪圖

再補充一下 pyqtgraph 重新繪圖的兩個方法

第一個是用 QApplication.processEvents(), 例如

pw = pg.plot()
while True:
    ...
    pw.plot(x, y, clear=True)
    pg.QtGui.QApplication.processEvents()

第二個是用 QTimer

pw = pg.plot()
timer = pg.QtCore.QTimer()
def update():
    pw.plot(x, y, clear=True)
timer.timeout.connect(update)
timer.start(16)

不過照這樣看來, 這篇就多此一舉了

http://stackoverflow.com/questions/18080170/what-is-the-easiest-way-to-achieve-realtime-plotting-in-pyqtgraph

[程式語言] 動態繪圖

這篇寫得很好, 如果要做動態繪圖, 基本上有這三個方法

1. 重新繪圖(re-plot)
2. 移動曲線(curve)
3. 移動視角(view)

http://stackoverflow.com/questions/24197910/live-data-monitor-pyqtgraph

[RPi] reset password

記得某個版本的 image 重設密碼怪怪的, 剛剛測試 2016-09 是好的
http://www.mapledyne.com/ideas/2015/8/4/reset-lost-admin-password-for-raspberry-pi

[Arduino] Arduino Timers and Interrupts

大家都推得這篇, 我倒是覺得這篇寫得比較好

reference:
* https://arduino-info.wikispaces.com/Timers-Arduino
* http://www.robotshop.com/letsmakerobots/arduino-101-timers-and-interrupts
* http://maxembedded.com/2011/07/avr-timers-ctc-mode/

[Python] pyqtgraph

這感覺很快
http://randomsenseless.blogspot.tw/2013/12/live-plotting-of-data-from-serial-port.html

[Security] 小米手環逆向工程

先隨便紀錄一下吧
* http://thinkingiot.blogspot.tw/2015/03/ble-2.html
* http://thinkingiot.blogspot.tw/2015/04/ble-4.html
* http://thinkingiot.blogspot.tw/2015/05/ble-5.html
* http://thinkingiot.blogspot.tw/2015/12/ble-5-sniffer.html
* http://en.miui.com/thread-53761-1-1.html
* https://github.com/lwis/miband-notifier
* http://www.cnblogs.com/jarvise/p/5153291.html
* https://read01.com/ARQO.html
* http://www.freebuf.com/news/88281.html