Public Lab Research note


IR filter switchers

by mathew | March 13, 2013 03:11 13 Mar 03:11 | #6315 | #6315

following up on my IR/Visible light camera dreams, I've been tracking down a component from the inside of security cameras: a solenoid-driven filter switcher (IR-CUT or IRC filter)! this a device that can quickly slide one filter in place of another, allowing a near-infrared night vision mode. IF it switched fast enough, a hyperspectral photo could be compiled from multiple images taken with a single camera. I'm seeing times for filter switching ranging from 40-200ms. 40ms might be fast enough to take two rapid succession photos without too much blur.

Its hard to find the individual components, but they should be cheap, as they appear to already be integrated into some cheap M12-mount security camera lenses. Shenzhen Zonhen Electric Appliances Co., Ltd is listing bulk orders at $1.10 all over the internet, but they aren't returning my e-mails (bad sign). ShenZhen VERITION technology Co.,Ltd has two different models listed for $15.

Optitrack filter switcher, $50

Leopard Imaging Inc. filter switcher, $20

5v filter switcher, 200ms, $25 it was good to find a speed rating!

40ms dual filter switcher

Filter Wheels

less attractive and slower are filter wheels, like this $6 filter wheel for the iphone

Here's an awesome arduino-powered one just for doing science.


4 Comments

Awesome! This is totally great Mathew! Nice one!

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Thanks Cynthia, and thanks for following our development process, I really appreciate getting feedback from someone with professional experience like yours. Would you consider joining the PLOTS spectrometry list? groups.google.com/group/plots-infrared

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Hi Matthew,

Thanks! Have you found any additional filter wheels worth considering since making your post?

http://publiclab.org/notes/WhiteRabbit/07-25-2014/can-infragrams-provide-useful-measurements-of-thirsty-my-lawn-is

Just a thought: if you started with a security camera that had one of the filter switchers as your base camera, then it might go more easily as you wouldn't have to worry about how to bolt one on after-the-fact.

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I haven't-- the security cameras with these built in are pretty expensive new. I was excited to find that the part itself was affordable. @noctividus has a note on a raspberry pi camera knock off (same sensor) that takes m-12 and C-mount lenses. I've been meaning to buy one and try with the filter switchers I have designed for those mounts. http://publiclab.org/notes/noctividus/06-25-2014/raspberry-pi-ndvi http://www.uctronics.com/raspberry-pi-noir-camera-board-cs-mount-lens-fully-compatible-with-official-module-p-1902.html

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