638nm 80mW (single-mode) Pen + Beam & star photos

I recently put this laser together for another guy here.

Here is a sort of guide on how I make my pens:

Components:

• 650-G-1 Lens
• Brass lens holder
• Cu & Al module
• Chrome pen host
• SS focus ring
• ML520G54 diode
• Groove 2 driver

The module is pretty straight forward...
I solder the driver directly to the diode. This keeps things nice and tidy.
A wire connects the driver's + input to the switch through the hole in the back of the module. A heatsink can easily be added to the driver if needed. A spring goes in the back for the + battery contact. I cut off the nub at the front of the driver "tray" so that it is flat and can be glued to the back of the module with epoxy.



The switch is soldered to a piece of pcb cut and filed to fit into the black driver tray. The switch pcb is glued into the tray and the tray is glued to the module. I make a mark on the module to indicate which way is "up" for the diode. This way I can align the bar of the diode perpendicular to the top of the host. Basically, the bar through the beam will be horizontal when the button of the laser is facing up instead of at a random angle. It also is needed so I can align the switch with the hole for the button.



Once the module is set up, the lens and focus ring are installed focused to infinity.
The module is then pressed in so that the focus ring is flush with the pen casing. This ensures that when the focus ring is screwed in fully, the beam will be parallel - so the laser can be pseudo-fixed focus.





The batteries are installed and the laser is fired up. My favorite part.




This laser doesn't make much heat, so there is enough mass to keep this laser stable for 5 minutes continuously. But this is intended for momentary use.



I love the wavelength and the beam shape is awesome. Divergence is nice and low.

75mW 638nm vs. 10mW 532nm


Same two lasers as above aimed at the Pleiades star cluster


The Andromeda galaxy this time


I really like this laser and almost wish I didn't have to send it away.

Hope you all have a good holiday (for those in the USA).

Thanks to Flaminpyro, DTR, and Jayrob for the components!

Later...

Oh yeah... I should probably make a reminder to always check the power source first if you have a problem. I thought that the diode was dead and almost threw it out because I was using a dead battery!

Re: 638nm 80mW (single-mode) Pen

Nice work. I am glad there is still innovation in the penlaser. I have that Newwish penlaser too. Some day I am going to revive it.

What batteries are you using ?

Re: 638nm 80mW (single-mode) Pen

Blord said:

Nice work. I am glad there is still innovation in the penlaser. I have that Newwish penlaser too. Someday I am going to revive it too.

What batteries are you using ?

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Thanks!

1 or 2 10440s can be used.
I usually like to make my pens with Flex drives so I can use Alkaline primaries, NiMH rechargeables, or Li-Ion, but since I am using a Groove 2 it needs at least 3.3V. The Groove 2 was the only available driver I knew of that would fit inside the module and wasn't made for 1.8A. I wish the Flex V5 would come back or the other divers were smaller.

Awesome looking laser, chrome pen hosts are my favorite. Wish I had the skills to make something like that.

2007Revolution said:

Awesome looking laser, chrome pen hosts are my favorite. Wish I had the skills to make something like that.

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It's pretty easy. There are few components and only 8 points to solder.
The hard part is not playing with it while the epoxy is still wet.

Kind of a side question but what kind of camera and settings do you use for those shots?

I'm surprised how bright the beams look for such low power and how clear it makes the stars look...

Maybe it has to do with the amount of light pollution (or lack there of) where you live.

eugene420 said:

Kind of a side question but what kind of camera and settings do you use for those shots?

I'm surprised how bright the beams look for such low power and how clear it makes the stars look...

Maybe it has to do with the amount of light pollution (or lack there of) where you live.

Click to expand...

The star photos were taken with a Canon 60D and Canon 85mm f/1.8 lens.
The settings: 2 sec. f/2.8 ISO2000. I don't remember what values the Andromeda image was taken at.
A lens with a wide aperture and shooting at high ISO helps to expose the stars with a relatively short exposure time to avoid trails.
Sometimes, in order to clean up noise, I will take multiple identical exposures then manually align and average them in Photoshop. This process doesn't boost exposure, just eliminates color and luminosity noise.

Where I live there is plenty of light pollution. To take these photos I had to wait until the object was almost directly overhead (to minimize atmosphere and get better contrast) and I shot these on a clear, moonless, cold night after the rain.

The star cluster above as well as the Andromeda galaxy are some of the brightest naked eye objects outisde our solar system. The Orion nebula is another one. I didn't like how the shots with Orion came out, though. A longer focal length would have been better to get a tighter frame.

If I really want a good shot of the night sky I go to the desert. The milky way is easy to see out there.

To get the beams to appear bright, you can do several things... either increase the exposure time or make the angle of the beam close to parallel with the camera's line of sight.
You may notice that a beam will appear brighter when pointed away or toward you, and less bright when the beam is perpendicular to your line of sight.

Just curious...how much would getting something like this made from you cost? Feel free to PM me...just curious. And what to you mean by "the bar"? I haven't ever seen a 635nm laser(yet...I have a 300mW mitsu on the way...obviously multimode but still...) so maybe I am just unaware of something.

Thanks,
Isaac

wannaburnstuff said:

And what to you mean by "the bar"? I haven't ever seen a 635nm laser(yet...I have a 300mW mitsu on the way...obviously multimode but still...) so maybe I am just unaware of something.

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Below is the 75mW 638nm on the left and 250mW 655nm (LPC-815 diode) on the right.
Both are using a 650-G-1 lens. A 3 element Aixiz lens does not show the bar through the dot as much.
I align the module in the host so that the bar is horizontal when the button is facing up. Does it make more sense with the picture?
I like doing it this way just for aesthetic reasons.

I rather like it. Good work OP.

great astro pictures +1:beer:

Omg i love your star pictures !!!! Where is that at !!!!!!! +1

Billiam said:

I rather like it. Good work OP.

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cheech226 said:

great astro pictures +1:beer:

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Keiichi tsuchiya said:

Omg i love your star pictures !!!! Where is that at !!!!!!! +1

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Thanks.
I took these pictures at home. Just a regular California suburb.

Nicely done Daniel :beer:

Nice and slick, what can i say.... it's fabulous!
I like the picture with the blue glow of the lens!
It's a perfect fit with the right tools overal.

+1

:wave:

Thanks for sharing :thanks:

p.s. Nice knife btw, is that a leatherman ?

Cheers, Sm..

Thanks. I think this laser came together really well. I can't wait to stick a green diode in one of these.

The knife isn't anything fancy - just a CRKT folder.
It's a really solid knife, especially for $45.
I use it for everything from outdoors and around the house. It's all banged up and the blade is pretty worn so I'll have to replace it soon... Not that it wears out easy, I just use my knife hard and often. And it's pretty old.
And I LOVE the Auto-Lawks feature. Really good engineering that makes opening and closing the knife a breeze. I'd recommend it as an EDC/general purpose knife any day. Great value and great construction.

It's ok to go off topic in my own thread, right?