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Kaidomain 50mW CR2 - inital review

Benm

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So if the protection diode is in series prior to the elctronics, it is producing the 0.7+/- volt drop and should work out great to drop off the extra voltage from the rechargable. (and the waste shouldn't be that great on the battery?)
Exactly. The 0.7 volt drop usually is just a loss, but in this case it matches your overvoltage quite well. So if you're affraid that the extra voltage from a rechargable will blow up a product that normally runs on primary cells, just put a diode in series and be done.

Putting one anti-paralel wilt the laser diode will have no effect, nor any use - it would act as a safeguard against static buildup before the diode is connected to a driver, but after that i see no reason to use one.
 

IgorT

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Benm said:
I guess that would be double then, but it might help stabilize power. Otherwise, you could simple wire a diode in series to create a 0.7v additional drop, presenting ~3.0 volts to the driver from a rechargeable.
Yes, but from what i've read, these lasers don't have any real driver in them, to keep the output stable, over most of the battery capacity, as it's voltage drops..


Since i'm thinking of having a batch of the LM3410 PCBs done (as current drivers for lasers from only one LiPo cell) , i might just stick one in there, since it matches the requirements and would keep the output "constant" even when the battery would be almost completelly empty.. If i decide to do them, that is...


Untill then, i'll use a diode.. Wouldn't want to kill it, even if it is cheap.
 

Benm

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Your own board will probably be better... it's amazing how bad some of the drivers in laser pointers are really. A constant current source isn't that hard to get right, even if its just a plain linear regulator.
 

IgorT

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Benm said:
Your own board will probably be better... it's amazing how bad some of the drivers in laser pointers are really. A constant current source isn't that hard to get right, even if its just a plain linear regulator.
Yeah, but the problem is, for a current regulator like that, you need double the voltage.. They want to make the lasers small, which i can understand...

But this is exactly the reason, why i'm considering having that 3410 circuit proffesionally done. It would allow driving of pretty much all lasers from a single Li-Po or 3 Ni-MHs.. Unfortunatelly, i can only have the PCBs done in hundreds... I wonder how many other people prefer their lasers small?


Anyway, i just ordered this Kaidomain 50mW laser. Hope it gets here soon and that it works.
Something weird happened when i ordered tho.. When finished the payment via PayPal and clicked the "return to shop" button, i got a page saying "We thank you for your generous order of $0."

Is this normal?
 

IgorT

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Benm said:
it's amazing how bad some of the drivers in laser pointers are really. A constant current source isn't that hard to get right, even if its just a plain linear regulator.
I forgot to add:

I just remembered, that the simplest constant current solution for the Kaidomain 50mW laser would be the AMC7135, for running it off rechargable LiPos, down to 3.3V... 350mA seems like the best current for it, right?

I mean, it wouldn't be as efficient as the SEPIC converter, but many of you already have the AMC.. Why not use it? It's better than putting in a diode in series.


Just a thought...
 

Benm

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Probably, though mine uses a bit under 350 as it is (around 300 or so from 3.6v).
 

IgorT

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Benm said:
Probably, though mine uses a bit under 350 as it is (around 300 or so from 3.6v).
In that case you could just put in a resistor in parallel, to waste the extra 50mA, but get stable output..
Still better, than the output dropping with the battery voltage.


Too bad i remembered that after making an order at DX.... :(
 

IgorT

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Mine finally shipped, so i'm hoping i get it before the end of next week. I get stuff in only 6 days, after it leaves Hong Kong.

I also ordered two more for friends.. I hope at least one of them works good, two would be better.. But i'll probably have to wait another month, before i get the other two. And on their site, it says "in stock"..


I want to see, how it compares to the bad DX200.. Since i'm getting pathetic brightness levels, it could actually be better.
 

IgorT

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bob1122 said:
When did you order it? Still listed as processing for me.
Was that you i was talking to on their "forums"? How long have you been waiting?



Wait, let me check..

I ordered on 2.18. and it was shipped on 3.6.. They didn't notify me about shipping it, untill i ordered two more, and asked again.

Hong Kong post says processing for delivery to the adresee on 3.8. Once it leaves HK it should be here in only 6 days. If i'm lucky i'll get it next saturday..
 

iewed

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Mine shipped to the US yesterday, so I'm hoping to have it by Thursday/Friday. I've already received my batteries and charger from DX, so I can do a comparison to the battery they give you, to a fully charged DX CR2. But this will probably be the last thing I purchase from KD, their shipping takes too long.
 

IgorT

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iewed said:
Mine shipped to the US yesterday, so I'm hoping to have it by Thursday/Friday. I've already received my batteries and charger from DX, so I can do a comparison to the battery they give you, to a fully charged DX CR2. But this will probably be the last thing I purchase from KD, their shipping takes too long.
It's not the shipping, it's just that they say they have it in stock, while they don't.
It's the "collecting from manufacturers" that is the problem.


Which batteries did you order from DX? I ordered the Ultrafire 800mAh 3V batteries. But i have no idea what chemistry they have.

If it's a Li-Po with a diode, they should be charged at 4.4V to give the average 3V voltage. It it's a Li-FE-Po, it should only be charged up to 3.6V.. I tried charging it to exactly 3.6V and got exactly that, so it is possible, that it is a real 3V battery, and not a Li-Po with a diode.
 

iewed

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I ordered the Ultra Fire CR2's, I believe they're the same as yours. I should've rephrased what I said, when I meant their shipping takes too long, I was referring more so to processing time than anything else.
 

IgorT

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iewed said:
I ordered the Ultra Fire CR2's, I believe they're the same as yours.
What charger are you going to use for them? Does it have a special 3V setting?


I should've rephrased what I said, when I meant their shipping takes too long, I was referring more so to processing time than anything else.
Yeah, i know, that really is painfully slow..

And every week they say it'll ship in one week.

But now, when i asked about the next two, they said "when they get them".. :)
 




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