| Background In all began on one weekend - I was sitting at the sunlit side of the MRT train ( Mass Rapid Transportation) and was scribbling notes to kill time. Then I noticed the pen was reflecting the sun light towards my eye. An idea came to me and I rotated the pen and was following the continual specular reflectance interrupted by the bright reflectance from the metal conical tip.... an idea was born.. | |
| Experiment: Video Analysis of Specular Reflectance of rotating cylindrical object on short axis ( tumbling) with different geometrical end shapes. | |
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| Conceptual setup: I need a rotating device of some sort : handheld battery driven drill... gear alarm clock mechanism, toys cars... fans...stepper motors... but I settled on a US$6 gearbox kit from Japan ( see image above). | |
| The first 'object' to try on is nothing simpler from a pen. .... So first a hole is drilled through .... | |
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| It took less than a minute. Good that I have a small dia. drill bit. | |
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| Then the pen is threaded through the gearbox long axis. The Gearbox is G-clamped to a low wooden stool. The gearbox works on x2 1.5volt batteries. Simply flipped the switch .... | |
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| The "rotating pen" was imagined from a tripod video setup 3 feet away in morning indoor ambient light. To eliminate unwanted reflecting surfaces I have to use a black TShirt ( didnt do a good job as a black vanguard sheet covering the gearbox) . Using meteor detection software - UFOCapture , a screen capture above showing the still grab and the reflectance surfaces..: the tip of the pen, the rim and the pocket clip on the other end as well as the rotating shaft and the two holding hex nuts. | |
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| Video peak-hold image showing the different reflecting surface from the pen. I have to manually move the watec-902H video camera on photo ball/socket head to simulate a moving object and leave a movement trail . The central line is the reflectance from the hex nuts and turning axis . | |
| OK, the software registered the image well . A night shot will eliminate most of the unwanted reflectance... I need to scale down the length... and tried another oblique angle... | |
| Why am I doing this? For investigating a tumbling satellite light curve......Read the various Centauri flashes in my other page here. | |
| What is next : Start building up conical nose piece, rockets body... | |
| Comments/Suggestions ?? | |
| chiayk1@singnet.com.sg | |
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2005 Dec 11 /edited Dec 14 |
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