Introduction: Cheap High Speed Video Recording for Analysis in Physics Experiments
Video analysis has become a great tool for physics experiments from the classroom to space exploration.
Last year I was making a research experiment and the big problem was to figure out how to record high speed video for cheap.
The solution came from the video game industry: the PS3 eye camera. A device capable to record up to 125 frames per second and still available for less than 50 bucks. Bingo!
Lets get started! this is what you need:
* PS3 eye Camera.
* A really fast computer with a big had drive (high speed recording generates huge files)
* Open source video analysis software
* Drivers downloaded from Code Laboratories (free download)
Step 1: Camera Set-up
Download and install the drivers from Code Laboratories.
To enable the "Advanced Mode" just download the attached file called "cleye.config" and simply place this file in the same directory where your executable file resides. (CL-Eye Test.exe)
The path usually is c:\program files\Code Laboratories\
This will allow you to record in different formats like:
Resolution. FPS (frames per second)
320x240 15, 30, 60, 75, 100, 125
640x480 15, 30, 40, 60, 75
Step 2: Make Better Videos
The PS3 camera has a lot of advantages like great light sensitivity, a two position optical zoom, USB bus, free drivers for PC and low cost.
A very important piece of advice is to place the camera on a tripod, in order to do that you have to cut the camera base or stand to fit your own tripod.
Remove the camera holder from the tripod and cut the PS3 camera base to match that holder, a simple and effective solution!
Step 3: Recording Time! (Tips & Tricks)
You can get better results using the video recording tool from the drivers package. (CL-Eye Test)
A fast processor is really necessary to avoid frame-skipping, a recorded video will require a lot of space in your hard drive because every recorded file is in uncompressed format.
Try to not use a video compressor, if you don't know how to do it without mess with frame rates or what is the right codec, I mean one compatible with the video analysis software you are using, you will probably end loosing your time with a useless file.
Try not to use any other USB devices while you are recording, it may cause frame-skipping too.
Another effective and simple way to reduce frame skipping is to disable the "video Preview" option while recording, disable your wifi card and so on...
If you have not a really fast PC try to close any unnecessary program or process before, some antivirus programs may cause problems too.
This is important, a frame-skipping video is completely useless for software analysis.
This video is a sample from a recent experiment, a damping variable mass physical pendulum, recorded using a resolution of 320x240 and a frame rate of 100 FPS.
Step 4: Video Analysis Time
The most important and some times not so funny part is to analyze the recorded video.
There is a lot of video analysis software available, in this case I will suggest the use of Open Source Software, it is an excellent option, and it's FREE.
You can use Tracker or any other tool, but tracker has many useful features for physics experiments analysis. You can find a very good manual on the same website and a few examples for learning.
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