Scratch-built Unique Host

[wizard]

After spending a few days looking at quite a few very impressive builds posted here on LPF, I decided to design & build a rather different looking host. I wanted my laser to have around 2W to 3W and be as compact and portable as I could make it. I decided to go with a 9mm; I purchase the LED-Lens-Driver assembly (G-2-LFL) from DTR which simply worked great right out of the box. The following photos document the build...

Start with a 1" x 1.75" x 12" piece of 6061 Aluminum, and keep milling until you find the finished host.

The bottom view shows a few grooves which I milled into the beveled corners to provide a better gripping area, a few cooling fins, and the set-screw to hold the LED in place.

The X-drive board is mounted just behind the LED. The little red button is the main on-off push button switch.

The two 18650 batteries are wired in series and fit into two 3/4" drilled holes. You can also see the open battery access door.

The battery access door was one of the harder parts to make as it also contains a small spring operated latch. I salvaged the tiny spring from a Bic lighter. The smallest pins were cut from paper clips. The battery contact springs were salvaged from cheap LED flashlights.

The slide switch connects/opens the two batteries and acts as a "safety" switch to help prevent accidental "on" conditions. (Looking at this photo makes me want to go back and clean up the edges of the switch opening a bit better.)

Here's a look at the front end. The focus ring is recessed to protect it from accidental movement.

The final product!!!

 

[sinner]

This is one of those unique, never seen before kind of builds.. Appreciate you sharing in-depth shots of the build.. explainds quite a bit about the whole design!

I wouldnt use those switches though, I believe they cannot handle above 0.5A esp the microswitch.. They are usually rated at 50-100mA..

 

[wizard]

Thanks for your concern about the current limitations on the switchs I've used, but thus far at least, I haven't experienced any overheating issues or noticed any contact pitting. Truth is that many of these micro-switchs are vastly under-rated and can safely carry far more current (especially at the low voltage levels used by LEDs) than they're rated for.

 

[sinner]

A general concept is to go for slightly higher rating than the usage, This is consider a standard practice in electronics.. Making things work at hobbyist level is great in itself, I agree! :beer: The wiring looks pretty solid too.. :gj: once again!

 

[Leodahsan]

Using the switch to trigger a transistor/FET would lower the current flowing thru it to very low values.

Great host... you're really a wizard! :beer: +1 for you.

 

[Wolfman29]

Great build! Just one pet peeve - laser diodes are not LEDs! Hah.

 

[nueces]

Impressive. You may have started a trend.

 

[AnthoT]

Very nice, unique host but it works

 

[wizard]

:thanks: Thanks for complement Wolfman29,...and I'm somewhat curious as to why you don't believe that Laser Diodes should be called LED's?? Should we start a new thread for this topic, or is there already a sticky??

 

[Wolfman29]

Well the reason is simple - laser diodes emit coherent light. As a rule, LEDs do not. They are just two different devices. Completely different manufacturing processes. It'd be like calling an toaster oven a pop-up toaster. Here, we call them LDs. I'm pretty sure that's the industry norm.

 

[wizard]

Thank you all for all the positive feedback !!! The "flat pack" shape idea was something I wanted to try primarily because I wanted it to fit easily into my pocket. Mostly I've been using it to point out stars, various costellations, and the occasional planet in the night sky to friends and family.

 

[wizard]

OK Wolfman29, I can conform to the LPF standands and refer to Laser Diodes as LDs in future posts . However, I see more similarities than differances between LEDs and LDs as both devices fall under the broader catagory of "diodes" (both use a PN juction), both use very similar manufacturing processes, and even similar, often identical, materials. Let me point you to an interresting article from Jaycar Electronics that in part states:

Laser diodes (also called "injection lasers") are in effect a
specialised form of LED. Just like a LED, they're a form of
P-N junction diode with a thin depletion layer where
electrons and holes collide to create light photons, when
the diode is forward biased.

www.jaycar.com.au/images_uploaded/ledlaser.pdf

 

[cheech226]

Pretty cool idea of host design. I like it.

 

[wizard]

After reading a few posts about how hot the 3W 9mm LDs, like I use in this host, can get, I decided to see just how long my host would handle the heat. Since this host uses a "momentary" switch that must be held down with a thumb to stay "on", I simply kept the laser "turned on" while I watched a timer on my smart phone. After 5 minutes of continuous operation my hand was tired from holding the switch down and I elected to end the test; the entire host was only slightly warm, with the forward 1/4th being uncomfortably warm, but not yet HOT. I'm sure I could have kept the LD turned on for at least another few minutes & perhaps much longer, but I was personally satisfied with 5 minutes of continuous operation.

 

[djQUAN]

You should measure the temperature of the diode itself. Because if you have enough thermal resistance between the case and the heatsink, the diode can get very hot but the host would still be cool. (think: thermos bottle) I'm not saying your design is flawed, it looks good actually, just pointing out the proper way of measuring temps.

 

[NO4H99]

Very interesting host, looks solid too. Also curious as to how the heatsinking is compared to the normal cylindrical builds.