Kaidomain 50mW CR2 - inital review

[Benm]

I havent had much problems with DX support at all, they usually dont make much fuss about it and sometimes even just ship a new product without wanting a return. Guess they wont do that on lasers though.

Anyways, i was reading back a bit on your DX/KD transplant plans and decided to have a look myself. I wanted to put the diode and crystals from a DX20 into the KD50, but i've noticed it doesnt actually fit.

The DX (inner) barrel seems to be the same diameter as the one from the KD, just a bit longer. However, the thread between barrel and diode/mca is different! It is not possible to screw the KD barrel onto the DX diode/mca/driver since the thread on the latter is slightly wider.

How do you plan to put things together?

 

[IgorT]

Well, i haven't seen a DX20 yet. It was just, that i had a DX200 in pieces, when i was playing with the KD50s, and i noticed, that the modules look almost identical, except for the fact, that the DX200 module has the same diameter over the entire length, and the KD50 has a slightly wider part.

But where the top (tension adjust) ring screws on the KD50 module, the DX200 accepts the top tube with the apperture onto the same threads.

I tried putting the top KD50 ring onto the DX200 module and it fit. The length of the two modules looked almost identical, together with the drivers, but i'm not worried about small differences, because i was adjusting how deep the KD50 would be in its own head anyway. The lower ring will push it up in the head and make nice contact with the body. Especially if i manage to solder it to the module.


Of course the two modules are only similiar from the outside, inside they are completelly different in the way they are put together. But i don't want to replace just the diode/MCA assembly, but the entire module tube. The DX200 has a 9mm diode, so the build is much different.


If i wasn't replacing the drivers as well, i would just swap the module / driver part between the two lasers. I would not dare remove the diode to put it into a different module, even if it would fit.

When i say module, i am talking about the tube, that has the collimator screwed in from the top, and the diode/mca/expander screwed in from the other side. The only other difference between the KD50 module and the DX200 is that where the former has the tube in one piece, and stuff is screwed in, the latter actually has two pieces - the upper 2/3 of the module with the expander, and the lower 1/3 of the module, that screws into the upper and holds the big diode/mca/expander. When put together it has the same shape and size.


From all the bad experiences with aligning the crystals, i wouldn't want to take the laser appart any further than this anyway (i think of the module as the smallest piece of the laser, that still works as a complete laser).

I don't have a DX200 on hand right now, they should come in about a week, then i'll make some pics. It's actually a very simple swap, and if it wasn't for the driver, the transplant would take a minute (after the DX200 is appart of course).

 

[Benm]

Oh okay, i guess the DX20 is a different story then. Its inner tube is way longer than the KD50's, the output lens is over a cm deep in the tube there, not near the end as it is in the KD.

I build a driver for the DX20 that runs off 3.6 volts anyways, so i could use it with a 10440 cell and a dummy (or saw down the dx body). However, it still suffers greatly from dimming despite good current regulation.

 

[IgorT]

Sorry to hear that. What current did you use? And what was it before? Did you perhaps draw a board of the same size with the contacts for the diode, switch and the spring?



Oh, and BTW, my friend received his KD50, and it sucks. 40mW when cooled down in my peltier mini fridge, 25 immediatelly dropping to 15mW otherwise, with a spot that starts out round but turns into a freak. This laser again looks as if it was used, but i haven't seen it when he got it, and he did use it quite a bit in the meanwhile.

I feel bad, even tho it's not my fault. So out of four, two were good so far. I contacted KD about it, let's see what they say. He wants to give this to another friend and order two more, hoping that at least one will be good...

 

[Hemlock_Mike]

I think many of you with this nice 50 are having problems with that POS switch. It has always caused me problems -- even on my newest one.

CURE !!! DX has a nice little clicky switch (2005588) which can be fitted into the tail with little skill. Hefty switch and it works click on, click off. I've done it to both of mine.

Another point --- The UltraFire TR15270 Lithium worked good for me for a while and suddenly lost their POOP. They can't seem to output what they did as new.

Mike

 

[Benm]

I must say i havent had any problems with the tailcap switches that come with these lasers yet. I guess its easily diagnosed by shorting the battery to the housing anyways, i usually bypass the switch that way to measure current consumption.

Owning both, i favor the 30 mW from DX, which is the same price give or take a few pennies. Thermal contact in that is better, but it does use a lot more power and is rated 30 instead of 50 mW. Hard to tell the difference in actual power though,

 

[Hemlock_Mike]

I have sent Kaido several emules asking to buy a couple 808 drivers. My wonderful 50 finally crapped out -- a bit my fault -----

Not one reply from them. My old 50 is beat up and was still working at 50+ but something got loose and it went multi-mode. I broke a leg off trying to fix.

Why won't they reply to my request for a simple 808 diode???

Mike

 

[SenKat_Stonetek]

Mike - I gotcha covered on teh simple diode - it should arrive shortly It has a driver attached as well

 

[Hemlock_Mike]

Greg to the rescue as usual ;D
For the NOOBs -- Greg is a major contributor here. See his ads at Stone Tek Electronics at the top of this page.
Thanks Greg --

Mike

 

[IgorT]

So you're gonna be putting in a new diode? Let me know how that goes..

I took the diode out of a 30mW Rominsen, after it measured >200mW and put it into a KD50, no luck.. I can get 15mW out, but not more..

 

[IgorT]

I must say i havent had any problems with the tailcap switches that come with these lasers yet. I guess its easily diagnosed by shorting the battery to the housing anyways, i usually bypass the switch that way to measure current consumption.

I've had problems with the switch in each of them. Part of the problem comes from the fact, that the switch is not permanently mounted into the tailcap, and the spring gives way, so it falls in and loses contact.

Since i just made the "KDX200" transplant, and the CNI driver i used (only 0.39V dropout voltage!) was shorter, this problem became even more prominent. I fixed it by putting two small pieces of alluminum foil on each side of the switch, and pushing the switch back into place. It wouldn't just drop in, so some force was required, but now it is in there for good and the problem is gone. (I picked off the foil sticking out above the switch with tweezers)

The other part of the problem comes from the switch changing resistance. The slightest tap on the switch makes it jump between 0.5-2 Ohms. In the "KDX200" this doesn't matter due to current regulation. I can only notice it, when the voltage of the battery is almost too low for the driver to regulate. But since the KD50 is completelly unregulated, it can halve the brightness of my best one.


The switch is easy to take out of the inner part of the tailcap - you just remove the ring. And i'm sure some of the DX switches would fit.




BTW: I am quite shocked by the fact, that my best (and only surviving) KD50 puts out 76mW peak, 68mW average in five minutes at 290mA, while the "KDX200" peaks at 120 but almost instantly drops to 86mW or so, but at 600-700mA. The beams are hard to tell appart visually. The spot is a bit brighter and the area it illuminates as well, but i'm disappointed by the results of the transplant... The head actually gets HOT, so heatsinking should be better than in the pen body, which didn't even get warm. But i think the power was better there.. I don't get it.

 

[IgorT]

I just slightly improved the heatsinking in the "KDX2000" and the mode hopping would seem to be gone. At least untill the entire body is scorching hot.

It is now peaking at 150mW again, with the original wanna-be driver and a 3V Li-Fe-PO. I need to figure out the current somehow. Measuring it doesn't work, as it influences it too much. If i can figure out what the actual current is, i could set it to that with a real driver, and it could become a bit more powerful.

The Rominsed LD-030 would seem to offer better heatsinking due to the alluminum, even tho it is much less massive. When i get the second one, i will put this module in there, which will hopefully postpone the mode hopping even more and maybe make it more stable. The one that is in the rominsen now, doesn't really like too much heatsinking, but i don't have time to take it out.


EDIT: I risked putting a 3.6V Li-Ion into the "KDX200" and powered it through a DMM to lower the current a little bit. 780mA! But it would peak lower and have a sudden brightness drop after the peak. The 3V Li-Fe-PO on the other hand measures in at 680mA (looks like a much better power source than two Ni-MHs) and gives 120-130mW peak. Looks like the current i'm after is around 700mAh, maybe a bit more. Looks like it'll be two AMCs after all.

 

[kake]

This should have 3v CR2's, and not 3.6v CR2's, right? What charger is the best one, for charging "Rechargeable 3V CR2 800mAh Green 2 Packs TIARA" from DX?

 

[Benm]

Well.. i guess 3.6 volt batteries are likely to kill it after a while, so 3.0 would be the safe choice. I have charged mine with a charger intended for 3.6v cells, but that probably isn't the best way to go.

In the end i'd probably recommend sticking with 3.6v cells and ordering this laser from dx:
http://www.laserpointerforums.com/forums/YaBB.pl?num=1209648671

It's rated 30mW in stead of 50, but visually there is little difference. Manufacturer specced to run from up to 4.2 volts, i'd say its a better choice for the money.