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The 3500 mW 940nm Nightmare - a MODC build

rhd

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The 940nm Nightmare

There's some irony here in that I set out to showcase the universality of my MODC modules, and how awesome it is that they allow usage of a C-Mount diode in traditional 12mm heatsinks.... but then I went off and built the MODC into a non-traditional heatsink. For those just jumping, here's a discussion of the MODC: http://laserpointerforums.com/f40/modc-experimenting-c-mount-builds-3w-ir-progress-89056.html

Some people have asked how the diode is fixed to the MODC. It doesn't require thermal epoxy, and in fact as much of a fan of thermal epoxy as I am, I'm not using it here. Regular thermal compound is perfect, because the copper backing screws down tight and holds the diode secure (and adds to the heatsinking). Using thermal compound instead of epoxy means you can remove the diode if need be. Here's what it looks like:

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Here are the specs of the build:
- For a diode, I decided to use a 4W 940nm C-Mount.
- For optics, I'm using a typical G9 lens (thanks to the MODC)
- For a driver, I'm using a version of my 5A buck driver. I haven't named it, but to keep the revisions straight, my internal version/code name is 5AB22V04.
- For power, the build uses 2x 250mAh high drain LiPo cells.

The driver isn't tiny. I haven't done much working trying to miniaturize it, and you'll notice that the surface mount inductor pushes the limits of the term "surface mount" - it's pretty big. But the driver has been working well, and has no issue running from the VINs I've tested all the way up to 16V. For this build, the driver is only seeing an input of 7.4V (nominal) from the 2x LiPo cells.

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Here's the finished product. I know the black clicky isn't the classiest option, but for this build, I actually wanted a less pronounced button that would be somewhat recessed and more difficult to press.

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Here's the build next to some of it's kin. On the far left, you'll see the Ninja MKII (which was showcased here). In the middle, you'll see the NINJA MKIII, which was never showcased, but is the cooler of the two in that it has built in tactile feedback (which you can here, slightly, in the video that follows). On the right, is the 940nm Nightmare.

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Now, before I get to showcasing the build video video, it's worth talking about this wavelength. 940nm is IR, but it's a whole different beast from the 808nm we're more familiar with. At 808nm, must people can still perceive a faint red tint. At 940nm, you see absolutely nothing at all, not the faintest hint of anything, whatsoever. In fact, the old trick of using a webcam/digital camera to pick up the spot *barely* works. My cell phone picks up the wavelength, but it's fairly dim even then, and I have a couple other cameras that don't see it at all. This creates a very unique challenge when trying to focus the laser, and needless to say, introduces a need for very careful and cautious usage. In the video below, you'll notice that it I initially have some difficulty training its output on the LPM sensor.

Safety glasses (rated for 940nm) were worn in these videos.

A comparison of 2 blue NINJA builds (MKII and MKIII) to the 940nm Nightmare

https://www.youtube.com/watch?v=PLiYi3lR384&feature=youtu.be

And a black tape video.
https://www.youtube.com/watch?v=5zT3RqtcC7Y&feature=youtu.be
 

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Wolfman29

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Awesome bud! Very cool build. Could you get a shot of the front of the MODC?
 

ultimatekaiser

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Something like this wth minor mods would be excellent for my DPSS builds!
 

Atomicrox

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Excellent build! I really like those hosts. Do you mind sharing where you got them?
 
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Gadget

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Outstanding build!!! +rep for you!

Could we get a couple of closer shots of the diode mount? That looks like a pretty sweet rig you came up with, there.
 

sinner

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Excellent work yet again, I simply love the uniqueness in your work. +3 if it let me.
 

rhd

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Here's a test of another C-Mount in a MODC. Some people (including myself) will cringe at the messy setup, but this isn't a build, just a test.

808nm diode, I'm guessing 6W to 8W. It immediately maxes out my LPMs (the max I can measure is 3800mW).

I'm driving it using 2X drivers in parallel, and each driver internally parallels 2X buck drivers on the PCB. Effectively, it's a 4X parallel 2A buck driver setup. The diode is being driven at 8A.

Driver input is a 7.4V LiPo pack (1,000 mAh, and rated for 20C)


https://www.youtube.com/watch?v=fS0YNRpcJcU&feature=youtu.be
 
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Wolfman29

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We ever going to get to see the front of one of these bad boys?
 

rhd

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Awesome bud! Very cool build. Could you get a shot of the front of the MODC?

We ever going to get to see the front of one of these bad boys?


My apologies sir. I'm sorry that I didn't take a photograph within the 14 hours between your first and second request for one..... :gun:

If you check out the MODC thread, you can see the front (the photo been there since before you asked the first time). It's a 12mm round barrel. Very exciting ;)

EDIT: Is this more to your liking Sir Wantsalaot ? ;p

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Wolfman29

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Hey now =p No need to get all upset on me - I just didn't get a reply to my question. And I took a look at the thread - maybe I'm just not visualizing it right, but the first photograph looks like the back of the MODC? There is an Aixiz module pointing away from us, so I assume the C-mount rests on that side, not the side we are seeing? And I think that's the same for the second photo? Looks like wires coming out of the back, so I presume the front is towards the heatsink?
 

rhd

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Hey now =p No need to get all upset on me - I just didn't get a reply to my question. And I took a look at the thread - maybe I'm just not visualizing it right, but the first photograph looks like the back of the MODC? There is an Aixiz module pointing away from us, so I assume the C-mount rests on that side, not the side we are seeing? And I think that's the same for the second photo? Looks like wires coming out of the back, so I presume the front is towards the heatsink?

See my edited post above (edited to tease you even more..... and to answer your question)

:eg:

No aixiz modules involved. What you're seeing is the barrel of the MODC.
 
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Wolfman29

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AH! I see. I thought it was a module that is compatible with an Aixiz module or something. That is a lot clearer. It didn't seem obvious to me that that wasn't the case from the first two pictures.

The design looks really neat. A complete module! Awesome. That photo is exactly what I was looking for! :takeit:

You are quite the tease. On another note, what is that surface you always take pictures on? It almost looks like an optical breadboard if the holes were just little dips. Is it your work area?
 

rhd

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On another note, what is that surface you always take pictures on? It almost looks like an optical breadboard if the holes were just little dips. Is it your work area?

Hahahahaha, not even close....!

It's the top of a really nice cappuccino maker :)
 




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