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Sharp 638nm 185mW Pen

RA_pierce

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My collection is filling out now.
The latest installment is another chrome pen fitted with the Sharp GH0631IA2G 638nm 185mW diode.
The other two pens I have now are built with 462nm and 505nm diodes.
The threads for those builds are here:
505nm Leadlight
Pen Tutorial with 462nm diode

One note on the build:
I didn't know this diode lacks a case pin until it arrived. Case neutral diodes are usually great because I can solder the case pin to the negative pin to effectively make it case negative. I couldn't do that with this diode, so I cut the pin off an old, dead diode, crammed it into one of the notches in the diode case and soldered a lead from the driver negative input to my "case pin." I epoxied the pin in place for security but it probably wasn't necessary considering how good the fit was. See the first photo.

This is my new favorite laser.
Red diodes are efficient and, at this wavelength, quite bright. The beam characteristics are also very good. This combination of qualities makes a diode like this one well suited for a compact pointer.
The color is beautiful - an orangey-red. The last time I had a 638nm pointer was when a few 40mW diodes appeared.

It's driven conservatively to maximize lifetime and keep the wavelength low. It's powered by a Flexdrive and 2xAAA batteries and has a 650-G lens set for minimum divergence at 15 meters. It can run continuously indefinitely without overheating.

The third photo shows the laser pointed at a chimney 80 meters away in sunlight. It is a bit more noticeable to my eyes than is shown in the picture.
The fifth photo shows the beam width at 50 meters distance. The iPhone SE is used for scale.
In the last two photos, the laser is aimed at a rock more than 800 meters away.
 

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diachi

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Nice build, and nice pictures too! :beer:
 
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Hap

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I really like the picture showing those 3 lasers you have. :yh:

-Alex
 
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very nice set of builds,so you driven conservatively to maximize lifetime but what exactlypower did you chose?

also your beamshots at nice looks awesome.i love red:drool:
 

Alaskan

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Thanks for the photo's, always a treat to have members show us their new stuff/toys. Nothing wrong with 650 nm you can't fix with power :) but since that costs $ I've only been buying 638 nm orange-red.
 

RA_pierce

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very nice set of builds,so you driven conservatively to maximize lifetime but what exactlypower did you chose?

also your beamshots at nice looks awesome.i love red:drool:
I set the driver to 180mA then adjusted current slightly higher until the unfocused beam could just produce a wisp of smoke on black plastic.
I no longer have a power meter so I'm guesstimating output is between 180 and 200mW. The diode's datasheet states that the operating current is 215mA and I think it's being driven at about that current.
I typically set the driver low then adjust as needed to get the output power I want. Not having a power meter makes it more difficult.

It was pretty fun to make those photos. I haven't done that in a while. I may have to find a longer distance to point to and then make a hike out to the beam terminal.

I really like the picture showing those 3 lasers you have. :yh:

-Alex
Thanks! I'd like a couple more interesting wavelengths but it seems I'll have to wait a bit before something new (and affordable) pops up.

Nice build, and nice pictures too! :beer:
Thanks!
 

BowtieGuy

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Great looking build, RA, those single mode reds are some of my favorites too; I've always used the Opnext 120mW version from DTR, but they seem to have the same good beam characteristics. :)
Nice photos, good solid looking beam.
Now that you have your RGB rainbow, what's next on your build agenda? :thinking:
 
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RA_pierce

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Great looking build, RA, those single mode reds are some of my favorites too; I've always used the Opnext 120mW version from DTR, but they seem to have the same good beam characteristics. :)
Nice photos, good solid looking beam.
Now that you have your RGB rainbow, what's next on your build agenda? :thinking:
That's something I haven't decided yet.
I'd like to do something interesting and unique. I've got some ideas for laser-related "accessories" but I have to get back to Rich with the plans before that goes anywhere.

I'm jealous of styropyro's UV build but I don't want to copycat. I'll come up with something...
 

styropyro

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Just saw this thread, very nice build! I've built a nearly identical one, 185mW sharp diode with flexdrive in a leadlight, except mine was the black version. I recently tore it down (in hindsight for nothing) because I thought I needed a flexdrive. I'll have to put it back together.

I'm jealous of styropyro's UV build but I don't want to copycat. I'll come up with something...
Don't be afraid to copycat! The more 375nm builds the better. I definitely want to copycat the 488nm builds out there.
 

Shotgundrums

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Nice Pen!! I have a pen host. I don’t know what I want to do with it. I go back and forth. I’d like to do a nice sapphire blue. But, recently I’ve been looking at 660nm LPM-836 and others similar. Cheap diode at that... I dunno. I have three hosts I’m dying to put together. This shyte is a real illness :gj:
 




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