Setup for insects in-flight and results

Started Feb 27, 2009 | Discussions thread
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frans_vdm
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Setup for insects in-flight and results
Feb 27, 2009

During 4 months i've build a new laser setup to capture insects in-flight. This is not my first version, already 4 years i build different versions. But this time no more arms are used to hold the lasers and photodiodes for the detectors. Instead of this arms the lasers stay now on the frame lateral from the D200 camera. In total 4 lasers are used, 2 IR lasers for the focus measurement and 2 green lasers for me to point at the right part on the insect. This make room between the front of the macro-lens and the insects.

To detect if the insects in-flight are in focus, an extra macro lens is added to the unit. This second macro-lens capture the reflected IR laserlight if correct pointed at the centere of the camera picture. Into this second lens a single pixel photodiode act as a detector and give the analoog signal to an AVR microcontroller build into the lens. The IR laserlight is pulsed at high frequence. This give me the possibility to measure the reflected IR light and the environment light. Both measurements take only 20 us or 1/25.000 sec to calculate if the insects are in focus.

See the drawing:

This unit:

And the result:

The setup works nice also into the full dark. 4 extra highpower leds are added. 2 of this highpower leds are UV leds. Some insects like UV light especially if the light are pulsed at 170 Hz like this.

2 Flashes, SB800 - SB-80-DX are used. The flashes are set at 1/64 power manual to have a short flash duration near 1/20.000 sec. As you can see on the setup, a second compur1 shutter is added to the camera. This shutter opens into 5.5 msec, 10 times faster then the camera. A homemade hardware controller and 2 AVR microcontrollers are put into the frame of the unit. The hole unit weigh 8 kg and a shoulder strap is used to carry this into the field. I walk to the insects, even into the full dark at night.

Here an example from previous version, a moth at night:

More pictures stay also at my Flickr site: http://www.flickr.com/photos/fotoopa_hs/
Frans.
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http://www.pbase.com/fotoopa

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