nRF24L01 for Arduino

Arduino 需要無線電傳數據的話, nRF24L01+ 的確是首選.
在 2.4GHz 工作, 不用牌照. 而且一套兩隻約 $2 USD左右, 很平.

nRF24L01 是舊版, 巳停產.
可以的話找 nRF24L01+ 最好.

RF24 – NRF24L01 Driver
RF24 writer’s blog
arduino leonardo 的 SPI 接線方法和其它的有點不一樣, 詳見:
arduino leonardo 與 nRF24L01 連接方法

Step by Step:
1. 在 Arduino SDK 安裝好 “libraries”,
2. Re-Start Arduino SDK
3. 打開 GettingStarted.pde.
4. Upload 到兩套 Arduino 內
5. 兩套Arduino 同時接到 PC , 打開兩個 Com Mon
6. 在其中一個 Com Mon 輸入 “T” (設定為發送信息)
7. Done!

OpenCV Auto Rotation (Deskewing) 自動校正角度

利用 OpenCV 自動校正角度

Plan:
EMGU (OpenCV for .Net) -> Read image -> Display and confirm -> Save

Link:
Rotation (Deskewing)
http://felix.abecassis.me/2011/10/opencv-rotation-deskewing/
http://www.emgu.com/wiki/index.php/Working_with_Images

How-To use EMGU (OpenCV for .Net)
http://www.codeproject.com/Articles/257502/Creating-Your-First-EMGU-Image-Processing-Project
http://yy-programer.blogspot.tw/2012/07/emgucv.html
http://www.dotblogs.com.tw/chou/archive/2009/06/13/8812.aspx

How-to: Use Argyll Measure ambient light illuminance and color temperatures

C:Program Files (x86)Argyll_V1.4.0bin>spotread -a -T

Spot read needs a calibration before continuing
Set instrument sensor to calibration position,
and then hit any key to continue,
or hit Esc or Q to abort:
Calibration complete

Place instrument on spot to be measured,
and hit [A-Z] to read white and setup FWA compensation (keyed to letter)
[a-z] to read and make FWA compensated reading from keyed reference
‘r’ to set reference, ‘s’ to save spectrum,
‘h’ to toggle high res., ‘k’ to do a calibration
Hit ESC or Q to exit, instrument switch or any other key to take a reading:

Result is XYZ: 126.944753 126.491128 74.586799, D50 Lab: 109.452122 7.264811 22
.899546
Ambient = 397.4 Lux, CCT = 3893K (Delta E 3.694291)
Suggested EV @ ISO100 for 397.4 Lux incident light = 7.3
Closest Planckian temperature = 3832K (Delta E 2.825573)
Closest Daylight temperature = 3901K (Delta E 0.391812)
Color Rendering Index (Ra) = 81.4
======================================================================
Command detail:
-a Use ambient measurement mode (absolute results)
-T Display correlated color temperatures and CRI

spotread command detail