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A better green laser pointer?

jj236

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I'm considering getting another laser pointer mainly to use for astronomy, bird watching, general pointing.
Looking for:
1) Does the job of pointing/visibility very well. Not into burning.
2) If it does the job, then safety from anything accidental.

For reference:
I purchased 2 laser pointers from ebay (advertised as 35mw and 100mw) of the 302 type, 532nm
I don't notice a difference between the advertised 35mw/100mw. So maybe wattage doesn't make a difference for visual/pointing observation.
I would like to purchase something safer, and also use as a screen pointer.

Is there anything better?
What about these options:
1) Z-Bolt BTG-6-P (Premium). I like the solid look, but maybe it's not as solid as it looks.
2) Wicked Laser Nano (5mw or 15mw). I like the lockout feature, not sure if 15mw is that much better than 5w.

What about 515nm? Or 520nm? versus 532nm?
What about OSRAM vs. APC vs. cheap ebay?
What about beam width?

Or are they all really the same, unless you want to burn?

Thanks
 

paul1598419

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There are some 505nm laser pointers set to ~60 mW that are sold on eBay for $60 to $70. This is a direct diode laser, so it wont have issues with temperature like your 532nm one will. There might be one for sale in the BS&T section of these forums right now if you look for it. If so, it would be less than the eBay price. Good luck.
 

smallfreak

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I don't notice a difference between the advertised 35mw/100mw
This ist mainly because the 302-Type pointers use unregulated drivers. They may be anything between 30 and 80mW, but more likely to the high end. So it's quite possible the actual power is very similar and with no relation to the advertized "guess". Only a few of them are really measured with a LPM. You can get a dozen of them for a few bucks on eBay.

The Z-Bolt has the advantage, that it probably IS regulated to <5mW and thus within legal specs for a customer device. On the other hand, 5mW is a bit low for star pointing. It does work, but you always want to get a stronger one (I tried). At our site 10-20mW of green proved very rerliable, even with a bigger crowd where the viewing angle to the beam is bigger.

The wicked Laser Nano 15mW does seem to be more suitable for your application, compared side to side.

As Paul said, 532nm pointers have great beam quality but are pretty sensitive to temperature. You have to keep them roughly at room temperature to get a good beam, due to the complicated "Diode+YAG+Frequency doubler" setup. A 520nm direct diode green is much easier to handle under changing conditions and handles drops or knocks better. They are not as cheap as the DPSS pointers and the beam from the diode is less "perfect" than the one from a YAG crystal. But you only notice, when directly observing the spot on a target. There is NO difference watching the beam.

This changes with the real high power Multi-mode diodes, that really have horrible spots, or better "bars". But even these do produce a good "Laser Beam". It simply does not make much sense to shoot a 7W Laser saber into the sky, just for pointing at a star.

You should look at the battery type your pointer is using. Some types are very uncommon in certain countries.
 
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jj236

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What is a recommended 10-20mw 520nm green direct diode?
 

GSS

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Any single mode basicly,
Look at DTR's store and he has Osram PL520B and then the PL520B.. I think these are your best bet.
His sight also is a wealth of info and shows power potential of each diode with running them at different amps.
 

paul1598419

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You can also get a 505nm direct diode single mode laser diode for $30 or less on eBay. If you can give me the micro-printed number around the diode's window I can tell you the range of wavelengths for many batches I tested. Most are case positive, so you will either have to use the Blitz Linear driver from Survival Lasers or isolate the diode from the rest of your build. In the end you could get the diode, module, driver and lens for ~$50.00 or so. I have built many of these using the Blitz Linear driver. You might be able to get the diode at an auction on eBay for $15.00. I can help walk you through how to set it up.
 

smallfreak

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Hopefully it doesn't need to be more complicated than that.
The most difficult part is soldering and mounting the diode. Laser diodes are very sensitive to static electricity. The kind that builds up walking across a synthetic floor or waring clothes with synthetic fibers. You certainly know that one, as everybody gets a buzz now and then, touching something metallic. Especially in winter when the air is dry.

Static charge can kill a diode, even if you dont' feel "charged". So prepare your workplace with natural surfaces, avoid touching the leads as good as you can ans make sure your soldering iron is insulated or grounded correctly. It wont't explode on first contact, but since you know about it, you will be careful.

This precaution clashes a little with the necessity to make good physical und thus thermal contact of the diode with the surrounding metal to get rid of the waste heat. It might be needed to forcibly press the diode into the bore.

Which again clashes with the fact that those diodes can be damaged mechanically too.

So it is a good idea to start building from scratch with a cheap diode that might be easily replaced in case anything goes wrong.

With a pre fitted module you already skipped the mechanical risks. With attached driver you skip the static soldering problems too, so you essentially only have to provide a case (a host) and a battery. The battery end of the driver is not that sensitive to static charge.

You should select a host in advance or together with the module, since you need to know whether a 12mm or a 20mm module fits in. And it determines the type of battery you are going to add.
 

paul1598419

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All my soldering stations are earth grounded. My bench has a grounded mat on it and I also have an earth grounded wrist strap. I have never lost a diode to ESD. But, it is hardly ever dry around western Washington, so ESD is not really a problem around here. Also, my two solder stations are thermostatically controlled too, so I normally set mine to 280* C. That is not as low as the solders melting point, but it helps to transfer heat more quickly, thus less time trying to make a good solder connection.
 

Benm

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ESD risks are often over-estimated quite a bit. Surely a big static discharge can kill a diode (or virtually any semiconductor) under the worst circumstances.

The most important thing is to have everything at the same static potential - which does not have to be ground but preferably is - before you start working on something.

With many recent laser diodes they have 3 pins, 2 of which are used, and the 3rd is just connected to the case but not part of powering the laser diode itself. So if you're worried that a static potential between yourself, your soldering iron and the laser diode is a problem, you could mitigate that easily: touch the diode case with your hands, and touch the soldering iron tip to the otherwise unused pin on the laser diode before doing any further work. This will equal out static potential between all components to a fair degree.

As far as grounding soldering irons goes: I'd prefer to have them soft-grounded (via a 1 meg resistor to mains ground, than hard grounded with a straight connection between tip and mains plug ground. The soft grounding is ample to prevent any problems with static buildup, but the hard grounding can cause problems at times. I guess you should not solder onto live circuits, but sometimes i do and i would not prefer the soldering iron to cause a dead short to ground if i touch a connection with some (low) voltage on it.
 

paul1598419

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I can't say I've ever met anyone who solders to live circuits before. It certainly has never been an issue for me. My wrist strap is grounded through a 1 M ohm resistor, but I don't think my stations are. I have never tried to measure the resistance of the ground path. I might do that as I assumed it was hard wired to ground. I know my mat is hard wired to ground, but the mat is not a surface that could ever cause a short circuit to any live circuits. It dissipates any static charge over its surface to ground.
 

Lifetime17

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Hi Hak,
These sinks are machined all the way down touching the battery tube, and protrude out past the bezel ring. The diode in it is a PL520B and doesn't get hot at all . Might do a few Copper sinks for the 501b host too. Thanks buddy enjoy

Rich:)
 




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