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ArcticMyst Security by Avery

Targeting Laser

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Sep 7, 2008
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Hi Gang,

Just wondering what the best mw rating is for a targetting laser.
you know the sort to mount onto a rifle or crossbow.

It won't be for burning, just as a target aid.

Cheers

WR
 





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Real men use Iron sights.

Well, if you want red, 5mW is good enough at night. For daylight, maybe 2-250mW red.
>50mW Green will be good for daylight.
More than 100mW of green will be overkill at night.
 
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Hi! Welcome to the forums!
I think RA_pierce covered everything, you just don't want to go overkill on the mW.. or whatever you're targeting will fry up or get noticed very easily.
 
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The problem with laser sights is that if you want it to be visible in all conditions, reliable, and weather/shock resistant, it will cost you a fair amount of $$$.
A high powered red should be fine for most conditions and there are advantages to a red diode over green DPSS for example.
A diode laser will be safer for firearms because they have no optical elements that require precise alignment like DPSS.
However, for red to be visible in any condition requires a lot more power because it is not as visible as green DPSS lasers (you can search for the human eye sensetivity to different wavelengths).
So to make your high powered red laser operate efficiently means that you need sufficient heatsinking for your laser. This means lots of metal, which means you will have to make this laser large enough to dissipate the heat it will produce.

My recommendation for a cost effective, sturdy, bright laser sight would be one of the following:

635 10mW module ( you can get one at Aixiz) It's brighter than a 650nm red laser and since it is low powered it will not need lots of heatsinking

5-50mW 532nm module (you can get these everywhere, there is even a seller who recently posted some items for sale at good prices) 30mW should be sufficient for day (however not direct sunlight) and night

200+mW 650nm (stonetek.org has diodes and modles to put them in) this will be bright enough for most conditions and will be fun to play with. and you will want to play with it.

all the info on where to find these is here on the forums just use "search"

welcome to the forum :)
 
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Cheers boys,

I'm going for the middle ground of a 100 mW laser.
It should do the job without needing expensive heatsinking.
I won't be turning it on for too long at a time so with that, a driver and a case, it should be ok for mounting on the xbow.
 
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Ok dudes.

Just got the parts through from the Stonetek gurus.

I'm currently hunting for a master housing for the battery, driver and housing to go in.

My next question is:

What battery voltage is best for this driver.  I'm tempted to go with a 9V battery as these have a fair amount of charge.

The documentation says (for the driver) voltage LESS than 16V but 2.25+V above the operating voltage of the diode.

The diodes documentation says here 2.5V operating and 3V maximum!!  It's a bit contradictory.

Now I'm a bit puzzled as to whether a 9 V battery is too much for this diode to handle.

I have a 12v small lithium battery (23AE) but wonder if that, again, is too much.

Can everyone who reads this please let me now what the score is with voltages and diodes and if they go BANG if you use 9V batteries.  With the driver I reckon I'm safe with my gameplan BUT I'm still a bit unsure. I really reckon it should be ok BUT without heat sinks I'm riding a sinking ship.

Cheers

KM
 

Galdor

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What driver are you using??? Did I miss it somewhere?

If it recommends 2.25 above operating voltage of the diode and
assuming you are using a 16x diode that requires 2.5 volts you
would need at least 4.75 to 5 volts. More important than that is
the current your driver is set at. Are you buying a driver with a
pre-set current or are you building your own driver?
 
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The driver is attached.

I bought it from StoneTek, and I think they only sell one type.

I'd post links but I ain't got 10 posts yet :(

Maybe some of you dudes recognise the model??

Cheers

KM
 

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daguin

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Kirby-Morgan said:
The driver is attached.
I bought it from StoneTek, and I think they only sell one type.
I'd post links but I ain't got 10 posts yet :(
Maybe some of you dudes recognise the model??
Cheers
KM

That is a Rkcstr adjustable driver it needs 2.2V. Your diode needs 3V. You need at least 5.2V to run this driver and laser combination. The Rkcstr will take up to around 11V so your 9V battery source will work.

Is this driver already soldered to the diode? Is the driver's current already set for you? If not, you have more reading/researching to do before you put it in a host.

Peace,
dave
 
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Thanks for the intel mate.

Driver not yet soldered. I was gonna have the pot about a 1/4 turn clockwise for power then just test and adjust.
The minimum mA is about 34 or so so a 1/4 turn should crank it up to about 80 - 100.
I think its pretty straightforward once the driver and battery connector is soldered. Just getting it in the housing all snug as a bug and so it doesn't shake about should do it. :)
 
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Ok, just sorted the battery housing.

I'm going for the 9v battery and this is now in an old torch case.

Despite trying all I could do the housing was too small for the diode and driver.

So the plan is to mount the battery pack housing and laser separate on the Xbow.

Just gotta mount a switch, do some wiring and soldering then she should be ready for a test :)

Here's some pics:
 

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Ok, slight change of plan.
Gonna be using the original housing for the 9V battery and another housing entirely for the laser.
 
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I get just under 300 mA of juice (using the I = V/R) equation.
Is this too much for the diode to handle?

Wait!

Just done some checking via:

http://stonetek.org/shop/SLD1239JL-54.pdf

According to the manufacturers the max rating is 170 mA.

Now here's where it gets interesting.

The pot will only bring the current down to about 195 - 205 mAs at its maximum strength.
Personally I think this is kinda edge riding but I guess it is what it is.

Anyone out there running a rig like this at 200 mA+???

The diode housing is metal which will act as a mini-heat sink I guess.
I feel I'm in uncharted waters here though ! :eek:
 
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Ok, just checked on stoneteks site and 2 reviews rave and woo with stories of it exceeding 250 mA for long periods.

I'm not the worried now, the reputations will have to be its wings ;)
 




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