Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



Ehgemus fan thread, post your photo's of the host he built for you.

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,139
Points
113
Re: Want an unusual host built? Just ask Ehgemus - My RGB!

Yea, the 445nm is 2.5 watts of blue and thick, way out of proportion to the lower powered single mode diodes in both power as well as divergence/beam thickness. I will eventually replace it with a single mode 445nm. The 50mw rated 520nm green single mode diode is still holding up without a failure, it is running at close to 100mw, way over a safe output for that diode and without a driver, crazy to do that, but it hasn't failed yet. I don't let it run more than a minute or so at a time though, it's power does creep up as it gets warmer and will fail at some point if I let it run too long, or in time just from the hard switching spike alone, I believe. I've switched the green diode without a driver off and on a few hundred times by now, keeps on playing... fingers crossed. I really do need to order up a couple of modules from DTR and get this thing setup with all single mode diodes with drivers too, been spending my hobby money on other things lately, so on the back burner for now. I'd like to have a host built with three separate heads, one for each color, each mounted on a swivel ball and set screw, that would line them up perfectly parallel.

Also, I need to install some Teflon tape on those lens holder threads too, sometimes the beams get a bit out of parallel if they move just a little bit from vibration. The beams are far more parallel than I thought they would be, with that fix ought to be very close.

Edit: Here's a post on the PL520 single mode diode I found from DTR from 4-20-2013

On the PL520 murder currently 1A... and it still has not died. It just dims after 750mA and lights back up when the current is turned down like the 445's and the mitsu diodes when too much current is applied. These seem to also be some tough little buggers.
From this, it seems my diode is acting normal; tough.
 
Last edited:



Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,139
Points
113
Re: Want an unusual host built? Just ask Ehgemus - My RGB!

Ehgemus made another host for me :)

This host has a Aixiz module with a G2 lens (edit: changed to a 3 element lens) coupled to a 2 inch diameter PCX lens to expand the beam for low divergence, works great! The black barrel you see on the end is a pair of cylindrical line lenses built into a brass tube to turn the beam into a line (I later added to the host). This is intended to be used for signaling, having the beam expanded prior to the line lens transfers the reduced divergence to the opposite plane of the line (thickness) which allows it to be viewed at a high strength many miles away.

This can be carried in a private aircraft and used as a long distance distress signaling device, never to be used to flash aircraft except in an emergency to attract their attention, which is legal. I am a private pilot and this is a great device to have on board when flying in Alaska.

Ehgemus always does great work and does so very inexpensively, my local machine shop wanted 500 dollars to build something like this, Harold built it for a fraction of that price, amazes me.


The host has a focus thumb disk for the G2 lens built into it which cannot be seen from this angle, on the other side.
 
Last edited:

Pman

Well-known member
Joined
Nov 28, 2012
Messages
4,444
Points
113
Re: Want an unusual host built? Just ask Ehgemus - My RGB!

That thing is nuts:) Did it come with a baseball? I've got a host/flashlight I've never seen anyone else use that's about the size of a 2D maglight but more of an 18650 battery tube. Keep thinking about sending it to him for a custom heat-sink. Big reflector on the end and side button.
 

Laser Chick

Well-known member
Joined
Jan 26, 2015
Messages
1,265
Points
63
Re: Want an unusual host built? Just ask Ehgemus - My RGB!

Wow, Ehgemus has plunge cutting down to a science. No chatter marks or anything.
Very nice work and you say he keeps the price down. That is a labor of love. You figure cost of raw material, components, electricity, assembly and his time and he is barely breaking even and might even be building it at a loss. That is the difference between your local machine shop who is driven by profit and Ehgemus who is driven(I am speculating) by the love for lasers and being creative.
Thanks for sharing your pictures and total respect for Ehgemus! :gj:
 
Joined
Mar 17, 2015
Messages
879
Points
63
Re: Want an unusual host built? Just ask Ehgemus - My RGB!

Looks like a silencer on the end of a laser. Looks so awesome. I'd love to see a beam shot.
 

Pman

Well-known member
Joined
Nov 28, 2012
Messages
4,444
Points
113
Re: Want an unusual host built? Just ask Ehgemus - My RGB!

I would be a madman with a lathe. Good luck getting me off the thing.
 

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,139
Points
113
Re: Want an unusual host built? Just ask Ehgemus - My RGB!

This build was a test of a unusual expander setup using a de-focused 3 element lens shooting into a single PCX lens. If you build one of these, I recommend some way of being able to pull or push a sliding lens holder with its PCX lens to make focusing on the fly easier. With this setup I glued the PCX lens to a cylinder lens tube so the whole assembly slides as one piece. At some point I want to replace the heavy brass plano-convex cylinder lens holder with a light weight aluminum one. The reason for using a de-focused 3 ele. lens is solely to adjust the diameter of the spot of light it produces to closely match the diameter of the PCX lens producing an expanded beam and lower divergence from it, once adjusted to infinity focus.

There is a line of set screws running along the large tube on the other side to secure the lens and cylinder lens assembly tube so they wont move, once set. Will provide beam shots later after the sun up here sets far enough below the horizon for enough darkness, too light at night up here this time of year, but when the cylinder lens is removed even with 80-100mw of output power I am able to clearly see a nice pronounced fat beam when using it inside the apartment with the lights turned off and window shades drawn. I am looking forward for winter to come with dark nights to take some beam shots.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Edit: Removed the cylinder lens, put a 3 inch diameter lens on top which just happened to be at infinity focus when flat against the end of the tube. With a two inch wide beam output the estimated divergence is close to .02 mRad. The focus can be adjusted by unscrewing the head from the heat sink, there are enough threads for a wide range of distant focus, even enough range to be able to focus the fat beam into a small dot on something several hundred feet away. I believe I might be able to ignite a match at 300 feet if I had a 1 watt 520nm laser diode in it, depending upon how well my lens deals with the wider beam of a multimode diode.



Until I get something permanent machined, using black electrical tape to hold the collimation lens on top. The host came with a very nice sliding lens holder machined out of aluminum which goes inside the tube, but I found the optical properties of this lens are much better than the 2 inch diameter internal PCX lens I was using.​



Forgive me lens police, I did a bad, stood the end of the pointer on its lens for this photo but no lens was harmed in the taking of this photograph, no AR coating. Dimensions are approximate.

I am working on installing corrective optics to make the beam more round using two cylinder lenses but not sure they will work in this expander output configuration as the beam will be about 10mm wide if only 10mm from the output of the 3 element lens (where I think the first corrective lens would need to be), thus the cylinder lenses must be wider than that. Also, I am not sure if cylinder lenses can be used to correct a beam which is not focused to infinity first, or if when passing through two cylinder lenses the beam will be able to expand enough to cover most of the diameter of the output PCX lens as I don't have them to test with yet.

Without corrective optics, the beam is about 50mm X 25mm or 2 X 1 inches diameter, after expansion at infinity focus and this is with a PL520 single mode laser diode. Without corrective optics, I believe the beam will have a far more pronounced fast axis with a 1 watt 520nm laser diode which I intend to install into the host next:

 
Last edited:

The Lightning Stalker

Well-known member
Joined
Aug 14, 2013
Messages
2,655
Points
63
Re: Want an unusual host built? Just ask Ehgemus - My RGB!

Ehgemus did a very nice job. Is that real
carbon fiber in the handle?

A big thick 1W green beam will look excellent
in fog or haze. Up there miles from any
airports, you will be painting the clouds.
 

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,139
Points
113
Re: Want an unusual host built? Just ask Ehgemus - My RGB!

Ehgemus used faux carbon fiber for the handle, but I find it very durable and hard. Gotta keep 5 miles away from small uncontrolled airports, 10 or more from larger controlled airspace airports or one is asking for trouble, even if completely innocent of pointing at aircraft someone might just turn you in for doing so.
 
Last edited:

APEX1

Well-known member
Joined
Mar 17, 2015
Messages
1,119
Points
63
Re: Want an unusual host built? Just ask Ehgemus - My RGB!

whoa. That thing is bad a**
 

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,139
Points
113
Re: Want an unusual host built? Just ask Ehgemus - My RGB!

Had to wait up until 3 AM in the morning for the sky to get dark enough for a beam shot, but here ya go :)

~1200+ mw of output power @ 520nm :)



You all with your wimpy little thread-like beams, behold the power of thick! It's pointy like a sword piercing the distance with little divergence. You don't get that with a 2mm diameter beam-width, DPSS or not. With the new high power green diodes, we don't need thin beams to see them in the night sky anymore :)
 
Last edited:

crazyspaz

New member
Joined
Jul 4, 2012
Messages
2,862
Points
0
Re: Want an unusual host built? Just ask Ehgemus - My RGB!

Ehgemus is fantastic. He made me 3 heatsinks, 3 focus adapters, and 2 battery adapter tubes for 45$ shipped! Can't beat his prices anywhere :D
 

doubleone44

Active member
Joined
Aug 26, 2014
Messages
259
Points
28
Re: Want an unusual host built? Just ask Ehgemus - My RGB!

Alaskan, that is one heck of a beam. I'm jealous. Also, we need to rename this thread to "Ehgemus fan thread" as we would be getting severly offtopic if we wouldn't :p
 

Ehgemus

New member
Joined
Feb 28, 2009
Messages
1,385
Points
0
Re: Want an unusual host built? Just ask Ehgemus - My RGB!

Great beam shot! Love it.
 

Alaskan

Well-known member
LPF Site Supporter
Joined
Jan 29, 2014
Messages
12,139
Points
113
I really like the fat beam, knowing its divergence is so much lower than a normal laser pointer is a real kick for me. I changed out the 50mw rated 520nm laser diode to one running at about 1350mw of raw output, being pushed hard at 2.4 amps to produce about 1200mw after lens losses. I bought the new NDG7475T 520nm diode from Taiwan on ebay for $200.

I want to add some more optics inside to correct the beam to be more rounded, if that works out, I will post the results.

I'd be happy to have others post pictures of their Ehgemus hosts here.
 
Last edited:

Minamoto Kobayashi

Well-known member
Joined
Aug 25, 2010
Messages
502
Points
63
Hello.
My best compliments for the two builds, I'm really jealous !!!:drool:

Only a question about beam expanders: Jetlaser expander is Keplerian type (two lenses), while Laserglow expander is Galileian type (three lenses).
Tonight I tried to replace, with a custom adapter, the original Laserglow expander with the Jetlaser expander in my Hercules laser.
Jetlaser BE works very similar to the one that You have built.
The results was not so good: the min focus obtained was at about 2.5 meters against the 30 cm of the original Galileian type.
Then, in the Laserglow BE needs only few twists to modify the focus from near to the aperture to the infinite, while in the Jetlaser needs many many twists to focus to the infinity.
Finally, the focus was not concentrated in one tiny point, but spreaded in a major surface.
In fact, as You can see here:



the classical PCX lenses (probably used in the Jetlaser expander) do not have all the rays focused in one unique point.
 




Top