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Returning - basically a newbie


Steve Steve
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  • 3 weeks later...
Posted by Don Fry on 23/01/2018 17:53:04:

What are you snapping?

Sorry about the delay in replying Don, I was away for work. Ultimately I am going to be monitoring vegetation with a downward-pointing Canon camera modified for near infrared.

First step see if I can still fly! I am in the process of building a simple 36" wing with just three channels to potter about and find my coordination. After that something larger, I currently have a 70" design on the board.

Cheers,

Steve

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Posted by Don Fry on 08/02/2018 18:36:14:

Denis, bit intrigued, in a previous life, I used UV film for some jobs. I have a vague memory, physics lectures, that a glass lens stopped IR.

I still have the gear Don, and you can still buy IR Colour Film

Even in the past, this was a very expensive pass time which was never justified

You had to keep accurate exposure notes, linked to lighting conditions, as you were making exposures against something you couldn't see

The lens had an IR filter on the front which you could not see through, and framing was a mystery too

The flash, at night was also filtered, and light could barely be seen coming from it

Images were disappointing, but very arty, and just sometimes, more by luck than design, I got acceptable " not of this planet " sunsets

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Back in the day when I did 'wet' photography I could never afford the expensive Wratten filters and IR film.

Modern digital cameras are very sensitive to IR. There has to be a factory fitted filter over the CCD to block it or you'd get the ethereal pale trees etc. I have bought a 16mp Canon camera from eBay and I will dismantle it to remove the IR filter. Then fitting a different filter will allow me to get data that will allow for vegetation analysis of wetlands (NDVI). I am also testing small cameras on Raspberry Pi devices.

As to the 36” possibly it will be a bit skittish. I just happened to end up with that size while trying my new PWM controller and nichrome wire etc. I will bolt a small motor on there and give it a go. Apart from anything I'm re-learning lots about building wings!

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Here is the power supply for the cutter. A 0-30V 10A PWM motor controller and a volts/amps meter from eBay. Powered by a 6A 19V old power brick for a laptop it seems to work fine with 28 gauge nichrome wire.

pwm

 

Edited By Steve Steve on 08/02/2018 20:24:43

Edited By Steve Steve on 08/02/2018 20:25:04

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