1x and 2x 14500 Copper host.

[Mohrenberg]

I've been mulling over this host idea for a couple weeks now.

Keep in mind, this is ALL about simplicity & a CHEAP (in cost, not quality) host to build lasers with.

I'm shooting for a retail price of around $10-$15.

This host will be machined from pure copper, only has 2 pieces. The main body, and the tailcap.
The tailcap will NOT contain a clicky switch. It essentially has a plastic button with a copper washer and spring mounted on the bottom of it. Having your tailcap screwed on partly gives you the ability to press the button and use it as a momentary switch.
Screwing it down all the way forces the washer against the body and gives you constant on. So it will be Twist for on, Push for momentary.
I'm going for this design because it has no small moving parts like a clicky switch, and will not break.

Here's the weird part. The head just has a couple fins, with an 11x0.5mm threaded hole recessed in the center. You'll mount your driver directly on the diode/aixiz style module standing vertically with a spring (Just like a 523nm module) and slip it in and screw the module directly onto the host. When screwed in, the module will be flush with the head of the host.

Will run on 14500 batteries. I'm going to start with a 1x 14500 body, and probably get longer bodies for 2x 14500 (not sure what the extra copper is going to cost )

Depending on how well they turn out, I'll probably shoot for an 18650/ 2x16340 version next.
I'm going with 14500 because the larger batteries will require larger diameter hosts which will make it expensive.

The host is 20mm in diameter, 90mm long without the tailcap (Have not designed the tailcap yet)
That's a little over 3/4" diameter and just above 3.5" long.

I'm still learning how to use google sketch up (I gave up on autodesk inventor)
but here is a rough version of the main body.


How do you guys think this will perform in terms of heat sinking? It's essentially one giant heat sink, but everything will have to travel through the threads of the module and into the host.

While Copper is probably the best choice. I can't help but be drawn to the even lower cost of aluminum, and anodizing ability that comes with it.

 

[Mohrenberg]

 

[awillis2589]

So basically the where the back half of the module would screw on instead would screw into the host? If your going for 1 14500 that probably a boost drive will be needed for most builds. Good thing you have those Ben boosts.

 

[JollyKillBill]

Very nice.

 

[Mohrenberg]

Yeah, that's why I want a 2x14500 version too, for linear drivers

 

[BowtieGuy]

Good idea, hope you can make them work!
It looks like this tailcap will function similarly to the Ti-B from Jetlasers. I've heard some people complain about this design, but I think it works pretty good, especially if the threading is fairly substantial, since it will be in regular use. :beer:

 

[Mohrenberg]

I believe I got the idea from a streamlight penlight I had bought at Home Depot. It used the AAAA batteries.

I think it would just be an all around better design for a switch, gives you both constant and momentary, and it's a lot less likely to fail than a cheap chinese clicky switch. The threads will probably be M17x1.0 in the tailcap. I have to look up copper washer and plastic buttons sizes as they need to fit together..

I'm going to have 100 or so made as soon as the chinese get their butts back to work.

 

[sinner]

Copper Host, for.., holy shit $10-$15 thats why they call you chinese moh!! :na:

 

[Mohrenberg]

One problem I may face is making the driver slip through the hole as I screw the module in. I know my linear drivers, benboosts, and flex drives would all fit, but there may be some other drivers out there that wouldn't. I'd say between those three though it shouldn't be the end of the world....

I should probably order the springs tonight, as they are coming from china on a row boat...

 

[sinner]

Well other than rounds drivers, it should be okay.. which obviously is not going to be used in pen style build like this. And all other drivers i can think of are less than 11mm wide (8x11mm upto 9x12mm) which shouldnt be a problem i think..

How would you recommend heatsinking the driver.. I can imagine a build with a driver soldered to diode pins and a spring attached to the V+ input , and V- to the ground.. It is quite easily possible with isolated drivers to connect the -Vin to the diode's case to make it a ground connection..

 

[Bob_Boyce]

One problem I may face is making the driver slip through the hole as I screw the module in. I know my linear drivers, benboosts, and flex drives would all fit, but there may be some other drivers out there that wouldn't. I'd say between those three though it shouldn't be the end of the world....

I should probably order the springs tonight, as they are coming from china on a row boat...

Driver size is important for sure. The biggest problem with my mini builds has been finding drivers small enough to fit, with low enough dropout voltage to be able to drive a low to medium power red or IR from a single 3.7-4.2V cell, and be positive regulated so I can use it with case negative laser diodes. There's not much room for diode and battery isolation in mini builds. This might be an issue that you run into as well.

Flexdrives work great for this, but I refuse to pay more than $10 to $15 for a driver for such a low power build. Recently I've bought a couple of each type of driver that I could find, but so far none were suitable for case negative laser diodes with LDO for single cell operation. I guess I'm gonna have to design my own mini LDO positive regulated driver for this application.

Bob

 

[Mohrenberg]

I know the 1085 ic i use on the mohgasm has a dropout of 1.5v at 3A, according to the manufacturer. I have yet to see if the dropout is low enough at ~400mA to run it off one cell, but surely it would be. I would think the drop out would be much less at 400mA if it's really only 1.5V at 3A

I'm debating on whether or not to change the host to aluminum, and go with a 2x16340/18650 design. Not sure how well it would heat sink the module though, being aluminum, and only connecting at the threads of the module...

 

[grainde]

Id definitely be interested in a copper version! :drool:

You said it only contacts through the threading, but if the hole in the HS was drilled out flush with the side of the module (before the threads) it would be the same as, if not better than, most of the hosts on the market using only set screws.

A copper 18650 would be the best, as we could also choose a 2 x 16340 option, but Im guessing that will be slightly more than $15... :beer:

 

[Mohrenberg]

yeah the host would be a lot bigger, and i'm assuming the cost would go way up for copper.
I have yet to even get a quote on these, waiting for the chinese to get back to work....

 

[Bob_Boyce]

I know the 1085 ic i use on the mohgasm has a dropout of 1.5v at 3A, according to the manufacturer. I have yet to see if the dropout is low enough at ~400mA to run it off one cell, but surely it would be. I would think the drop out would be much less at 400mA if it's really only 1.5V at 3A

I'm debating on whether or not to change the host to aluminum, and go with a 2x16340/18650 design. Not sure how well it would heat sink the module though, being aluminum, and only connecting at the threads of the module...

I had hoped that the Mohgasm linear would work, which was why I bought a couple. But there were no size specs found for it so I just had to buy and see. Unfortunately, they are way too long to fit in the driver pocket of my mini host. The BenBoost driver even had to be installed at a 45 degree angle to fit because the orientation (polarity) of the LD pads caused the driver to be on the wrong side of the LD when used with the Oshram PL450B. To keep the driver from hitting the side of the driver compartment, it had to be laid over towards the case pin after soldering. The thickness of that driver made this difficult and still be able to fit. The flexdrives fit in there straight and have plenty of clearance.

Frankly, I don't nomally use these mini hosts for blue or 405nm builds. Except for the occasional hobby build for my own use, they are typically used for portable red or IR excitation lasers. They must be small enough to fit in a pocket and be carried around with ease because they are often used in the field. This is why I welcome a host such as this one that you are working on. But again, small size is paramount for these.

As for aluminum vs copper, copper is far better for heat dissipation than aluminum, but obviously aluminum is easier to machine. My current mini hosts are aluminum due to the low cost, less than $5 each as complete LED lights with batteries. They are not ideal, would prefer copper, but they have been serving the purpose quite well for a few years now. Because I may need to increase the number of these builds in the near future, per unit build cost is going to need to be carefully considered. This is also why I'm currently looking at alternatives to the flexdrive. All of my past red and IR builds in these hosts have been using flexdrives set to 200mA. I had bought a large quantity of them back when they were less expensive. I'm down to just a couple left and I refuse to pay the current price for them, not to mention the difficulty sourcing them in quantity when needed.

Sorry to sidetrack this discussion, but as you can see it is sort of related. If I'm going to buy many of your planned copper hosts, they would need to be a small 1 cell version, and able to fit a lower cost driver capable of driving a red or IR LD at 200mA. They must also be rugged enough to handle being carried about on a daily basis. The field techs drop them sometimes and they need to be able to withstand that to a degree. The mini hosts I now use have held up to this abuse quite well so far. The holsters help keep them protected on the outside.

Bob

 

[sinner]

Well i beg to differ on a few occasions.. firstly a 2x14500 all Cu host is a brilliant idea, Secondly the 20mm OD means you still have a very thick host body and not only that , its whole copper so it DOES work for higher power builds like 445nm & 405nm. Heck i've seen 16340 aswell as 14500 batteries and there is not much difference in the battery capacity or discharge rates if you're thinking about that.. I can guarantee this will be better than aluminium+bigger 18650 host..