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

I am very satisfied with the quality and as the novice to understanding machining that I am, I was amazed he could machine the cover cap to screw on to where the three output holes match up with the output of the lasers inside so nicely, perfect! Another nice aspect of the host is the three switches can be partially pushed down for momentary flashing of the beams without being locked on, but you can lock each color on if you want. Also, there is a on-off switch in the end cap which is a must, as the individual switches for each color depress too easily to be safe to handle without fear of accidentally flashing yourself or someone else when carrying it, if that off switch wasn't there which is recessed in the body of the aluminum tail cap.

Re: Want an unusual host built? Just ask Ehgemus - My RGB!

Cool! Gotta respect his talent on the lathe for sure. I had a triple diode host lined up with him at one point, not sure what happened to it...

What drivers are you using? What diodes? We need details

Re: Want an unusual host built? Just ask Ehgemus - My RGB!

Total combined R,G,B power output is about 500mw. Right now there are red and green DTR single mode modules in it which were purchased with the drivers installed, not sure which ones they are. The blue laser module is also from DTR but instead of a single mode, it has a multimode M140 diode in it without a driver. I can do that because I am using a single 26650 battery in the tube instead of two in series, because of this the voltage at 4.2 V isn't high enough for the M140 diode to ever get hot enough to cause the current to get out of control and only puts out 250+ milliwatts of blue, with this particular diode, two or three tenths of a volt less and the diode stops lasing so the battery must be close to full charge for the blue to work. I have a blue single mode to replace it with later, but don't have the driver installed for that module yet. Once I get the M140 replaced with the single mode one and driver, I can then use two 26650 batteries in the tube, for now there is a blank where the 2nd battery would be.

Here's a link to DTR's single mode diodes I used: https://sites.google.com/site/dtrlpf/home/diodes/rgb-diode-budle - For laser pointer use, these diodes can be run at higher output levels than he shows on his web page, as mine are. The advantage to single mode diodes, as apposed to multimode, is their divergence is much less and they can actually deliver more power at a great distance than the multimode diodes can do, even at 10-20 times more power the beams produced by multimode laser diodes spread out too much and quickly become diluted after several thousand feet while these relatively low power single mode diodes keep on going in a tighter beam

Ehgemus is an artist, I didn't give him any specs for the build other than I wanted three buttons and holes for three DTR modules in a tri-configuration and a tube for the two big batteries, the rest I left up to him to design as he wanted. I didn't expect to be disappointed and I wasn't Very nice work!

Re: Want an unusual host built? Just ask Ehgemus - My RGB!

How parallel are the beams?

I'd be curious to know if he could do something similar with 7 diodes, closer together.

Re: Want an unusual host built? Just ask Ehgemus - My RGB!

The beams are not as parallel as I would like, I can fix most of that by rotating a couple of the modules until they line up better. I think the biggest problem is the lens holders need to have some Teflon tape wrapped into them to tighten them up more. Also, if the lens inside is the least bit off of completely flat, you have the beam shooting off out of parallel. To do this right, there needs to be some kind of adjustment built in to make the beams parallel, I don't think they will ever be perfectly parallel without it, but I have a hand full of laser diodes to choose from until I get them well matched up too.

I've asked how many modules he can fit in a two inch head, he thought maybe 6 or 7 but I never asked him to confirm it. I have asked him to build another host without the laser modules, just to put holes in the head where I can insert lots of R,G,B diodes without optics and then add a single lens on top of all of them. I think it will work, not sure how far the focal points will be from one color to the other, that might make it impossible to focus all of the beams together if using one lens. I've been playing around with multiple uncollimated blue beams into a large lens and they just each pop out of the lens at the diode spacing with their own individual beams, so for a single color, it should be no problem.

Re: Want an unusual host built? Just ask Ehgemus - My RGB!

I was just wondering the same thing as rhd, I want one with blue/red/green/violet/and an LED flashlight. I can't afford it but now you have me thinking about such nonsense. I never should have looked at this thread!

Alan

Re: Want an unusual host built? Just ask Ehgemus - My RGB!

I was thinking of just putting three 1 watt 405nm 16X Blu-ray diodes in it, but I'm not sure it would be as fun. If I had a seven in one, that would be the bee's knee's, but lots of buttons! I'd want to be able to turn them off and on individually.

Edit: I really had this built purely as a test platform for experimenting with optics, but found out right away the spacing of the modules is too much to do what I want, thus my next one will just have holes for the bare diodes, but that presents another challenge too, trying to get the optics to work right with one lens, that one might not work out as I hope either, but fun to play with.

I wanted to expand the beams from each color to where they overlap into what appears to be one beam, still working on it, the next host with the diodes much closer together should be a big improvement towards that goal. I'm concerned that the colors won't be able to focus together correctly, but if expanded enough, the differences of focus with a single lens might be very apparent anyway.

I just fired it up into the night sky for the first time, the beams are pretty darn parallel, considering I haven't tried to tweak them in much yet, just one small adjustment of the green lens, pleased.

Re: Want an unusual host built? Just ask Ehgemus - My RGB!

3 or more 1W 405nm would be incredible! That could instantly set stuff on fire. It should have some sound effect too like a phaser or somthing to impress anyone you show it to. Have you tried a PLTB450B yet? That was my last build last year and it has a smaller beam, it will set paper in flames or burn most anything and it meters at only 1913mW, 3 or more of those would be really impressive, it is very bright.

Alan

Re: Want an unusual host built? Just ask Ehgemus - My RGB!

One of these multiple diode hosts would be awesome with some high power diodes in it, I will swap them out sometime and see what it looks like. For the 1 watt 405nm, I only have one right now, I'd have to buy two more to try it. What is nice about the 405nm 16X Blu-ray diode is although it is 1 watt (mine metered at 984mw at DTR's conservative setting), it is still single mode, just that it is only 15 percent as bright to the eye compared to 445nm blue, and 1 percent as bright to the eye as 520nm green.

I was very interested in the PLTB450B as a relatively low divergence multimode diode, as multimodes go, it's divergence was much better than the M140 blue laser diode but I decided to go with the single mode R,G,B diodes instead. The divergence math for them showed me a single mode laser diode can put a spot on a very high cloud deck, while multimode diodes can't. I tried it myself and it was true, I couldn't put a spot on a 6000 foot cloud deck with my 2 watt output M140 multimode diode while I could with a 80mw output green 520nm single mode. Of course, green helps compared to blue which is much fainter, but still, I was impressed with the lower power single mode diodes tighter divergence. However, close up and for burning, the lower power laser diodes aren't very impressive.

Re: Want an unusual host built? Just ask Ehgemus - My RGB!

Great work both you guys! Alaskan, do you really think your going to make a thread about this awesome build and only give us ONE BEAM PIC!? Come now, give us the goods!

Re: Want an unusual host built? Just ask Ehgemus - My RGB!

nwfreefly said:

Great work both you guys! Alaskan, do you really think your going to make a thread about this awesome build and only give us ONE BEAM PIC!? Come now, give us the goods!

Click to expand...

This^^^^

Re: Want an unusual host built? Just ask Ehgemus - My RGB!

I need to get the green diodes power turned up and replace the under driven M140 with a single mode diode so the powers are balanced between them first, then I will get some sky shots. The green is too weak right now which causes the blue and red to overpower it when trying to get a good photo outside.

Re: Want an unusual host built? Just ask Ehgemus - My RGB!

I agree, a great effort by both you and Ehgemus.I will definitely be watching for the revised version with the required beam shots! :gj:

Re: Want an unusual host built? Just ask Ehgemus - My RGB!

I posted another photo earlier which had the brightness turned up, decided to post the original instead. When I get the diodes swapped out and the green power adjusted I will add another, but this shows the beams are fairly parallel.

Edit: What I have now: Red and green single mode, blue multimode. Last night I put a driver on the M140 and was able to then power the lasers with two batteries in the tube instead of one. I also removed the old 520 single mode which I couldn't turn the power up on beyond 50mw and replaced it with another one without a driver which is now producing 100mw of output when the two batteries are installed. For the 520nm green diode this is far too high and dangerous to the life of the diode, noticing the power climb up too fast when it becomes warm now, so I am limiting the amount of time I have it on until I get a driver installed for that one. The 445nm 140M diode is putting out close to 2.5 watts now, the red still at 200mw. With the blue laser putting out so much power, it is far brighter than the 100mw green, I should be running the blue at 1 watt max so the beam intensities match up better but the red is still too dim compared to the 520nm green.

Through studies of the eye, it has been determined for most people the 638nm and 445nm colors are roughly 10 percent as bright to the eye as 520nm green. So, as a minimum, when running 80-100mw of 520nm green I'd balance the perceived beam intensities between the colors by choosing laser diodes so the red 638nm and blue 445nm power outputs are at least 500mw, but this is actually a bit low. Using RHD's brightness calculator (link in my sig.) both the 638nm and 445nm should be closer to 700mw output to closely match a 80mw 520nm green. For myself, I'm sticking with red and green single mode diodes because their divergence is so much better, but for blue, I'm currently using a multimode diode in there for now but will replace it with a single mode diode later.

If you want to build a host like this and don't care about divergence so much, for a good match, I'd put some 700mw 638 and 445nm multimode laser diodes in the host with a 80mw 520nm green single mode diode so at least one of your colors has low enough divergence to put a nice spot on a high cloud, doing so amuses me anyway. In the photo below, the green was only 40mw of output and still has a fairly bright beam to the camera compared to the red at 200 and the blue at closer to 250mw. When viewing the beams at these power levels the red was much dimmer to the eye than I liked.



Notice how much thicker or wider the blue beam is compared to the red and green single mode diodes? That's multimode for you.

Edit 03/21/2015: Anchorage has 7000 ft scattered clouds tonight and I was able to produce a terminus spot on the cloud deck with both the red and green far lower powered single mode laser diodes while the 2.5 watt 445nm M140 multimode laser diode couldn't even come close to doing so, that's the power of low divergence! Although I was surprised, this was the first time I've tried it with a red 638nm single mode laser and the spot stood out much brighter than the 520nm green, I didn't expect that. It's amazing to me that low power single mode diodes are actually high power at a distance, the multimodes petering out from their wide divergence, unable to put a spot on a high cloud.

Re: Want an unusual host built? Just ask Ehgemus - My RGB!

Wow, that really did turn out great. Thanks again. :beer:

Re: Want an unusual host built? Just ask Ehgemus - My RGB!

Yeah, this is a very interesting looking one of a kind type thing. Such an odd thing to hear someone say that the green isn't bright enough (until you took the driver out of the path). The reason why many $5 532nm pens are so impressive. Really looks like the 445nm is out of proportion to the others with that "thick" beam like you mention.