FS: >110mW PHR, >140mW 4x & >170mW 6x Blu-Rays

Re: FS: >110mW Blu-Rays - available

he did.. read it again.

the lens has threads on it which when turned (turning a dial) moves the lens closer or further away from the light, hence changing the focal point distance from the lens.

[link=http://en.wikipedia.org/wiki/Lens_(optics)]check this out for more info [/link]

Re: FS: >110mW Blu-Rays - available

It's not a dial.. The lens is in a plastic lens nut with threads. It is screwed into the module.

So if you turn the entire lens nut (holding it by the metal ring) in one direction, it basically unscrews, and comes further out. If you turn it several times, it falls out (and you lose the spring ;D)...

Every lens has a focal length. Well, actually two. One of them determines how far away from the source it has to be, to get a parallel beam. If you move the lens closer or further, the beam either diverges (i didn't show that, as we don't use it), or converges (for burning).

I don't know how to explain better, i would have to draw many beams for it, to show you how they pass the lens, and how it diverts them. But it's the same, as if you move a magnifying glass under the sun, to bundle all the light in a tiny spot, and then burn something with it.

Re: FS: >110mW Blu-Rays - available

Good link. Thank you Skater!

Re: FS: >110mW Blu-Rays - available

With Igor you not only get a laser but a beginners degree in laser pointer tech. Thanks Igor for all you've done for me off forum. Your a good man charlie brown.

Re: FS: >110mW Blu-Rays - available

usakicksass said:

With Igor you not only get a laser but a beginners degree in laser pointer tech. Thanks Igor for all you've done for me off forum. Your a good man charlie brown.

Click to expand...

HEAR! HEAR!

I second that.

Peace,
dave

Re: FS: >110mW Blu-Rays - available

Umm.. Thanks guys! I appreciate that!

I'm trying my best. But please understand, if i happen to be a little slow sometimes.
Between making the lasers, convincing lens manufacturers it'll be worth it for them to make four samples (instead of 30, like the first one), and answering emails, i sometimes even forget to eat, so... :

Re: FS: >110mW Blu-Rays - available

mm what's a q tip?

Re: FS: >110mW Blu-Rays - available

vizard87 said:

mm what's a q tip?

Click to expand...

Q-tip---is the plastic stick with cotton on the ends, that is used to clear out earwax from ears.



brtaman

Re: FS: >110mW Blu-Rays - available

vizard87 said:

mm what's a q tip?

Click to expand...

What brtaman said..


Otherwise, if you don't screw with the lens, it doesn't really matter. But i usually include a diffraction grating for a Liquid Sky effect, and it means removing the original lens, and then sometimes something gets in between..


So, while q-tips are not perfect for this purpose, it's the only thing available to everyone..
The best thing to do is not to get garbage in there at all of course! But that doesn't always work..

So if that fails, the next thing should be a small air-blower pump meant for blowing dust away - DX has these now - (but NOT canned air!!!!!!!!), and if that fails, it can be solved with dry q-tips, as long as you don't make it worse with "cleaning" fluids or impure solvents first.. You should NEVER touch the q-tip with your fingers, on the side that will be touching the diode window tho!

Usually blowing is enough, but again, it should not be done with your mouth. Otherwise you're spitting on it, even tho you don't see it.

Re: FS: >110mW Blu-Rays - available

My laser has arrived today,I was only able to play with it while was afternoon,it's starting to get dark here so I will be able to tell better what I think about it .The only strange thing is,I measured the current it's drawing from the battery,and it's drawing 180mA,isn't that too much?Or it takes more than 125mA from the battery but the driver only delivers 125mA to the diode?Because I have a red one that jayrob marked as 470mA and that's the exact current it's taking from the batteries.

Re: FS: >110mW Blu-Rays - available

the driver uses some current to do its work. jayrob must have measured from the batteries as well when labeling that, the diode is probably getting a little less.

Re: FS: >110mW Blu-Rays - available

Yeah, that's because Jayrob used a Linear driver - a 317.


A linear driver needs a certain amount of voltage more than the diode needs, but the current from the battery is ALWAYS the same as the current through the diode, right untill the battery voltage is too low, and the current starts dropping.


Since i like my lasers small, i make a boost driver for my blu rays, so they can work from a single 3.6V Li-Ion. A boost driver operates from a voltage lower, than what the diode needs, and boosts the voltage to the exact amount required for a certain current to flow through the battery, and then adjusts this voltage, to keep the current constant all the time.

So since the driver has to put out 125mA at 5.4V, this means it is putting out 5.4 x 0.125 = 0.675W of power (P = U x I)..
The battery has ~4V when full, and if the driver was only pulling 125mA at 4V, the input power would be 0.5W..

It's not a perpetuum mobile - it can't make power out of nothing.
If it has to boost the voltage, that means it needs more current, than it will put out.


So what happens is, it pulls a higher current at a lower voltage, and converts it into a lower current at a higher voltage..

Also, as the battery slowly discharges, and the voltage drops, it has to pull more and more current. So on an empty battery, the current draw from the battery will go close to 300mA. The lower the voltage, the more current it needs, to put out the same power.


That's why you're measuring a higher current. Power OUT can not be higher than power IN. In fact, it can't even be the same, due to the losses (>84% efficiency = <16% losses). So power IN actually has to be higher, than power OUT.

But 180mA is not that much! It means your battery must be very full. Did you charge them first, or did you just use them? My experimental units draw like 360mA from the battery, but that's because the output current is 170mA..

Re: FS: >110mW Blu-Rays - available

sk8er4514 said:

the driver uses some current to do its work. jayrob must have measured from the batteries as well when labeling that, the diode is probably getting a little less.

Click to expand...

The difference between the current in and current out with linear drivers is only a couple of mA. Not 55mA..

In fact, with linear drivers it doesn't really matter at which point you measure the current. It's pretty much the same all the way, as there is only one way through the driver.

So there, you can just as safelly (or more, cos you don't have to disconnect the load) set the current through the load, by measuring the current from the battery.


Boost drivers convert the relationship of power going in, and the power coming out, and at a high efficiency - the power out is not that much lower, than the power going in.

With a linear driver, you have to give it the current the load needs, but at a higher voltage.

For example, a red at 333mA with a 317:
The diode will be getting 333mA at around 3V = 1W of power coming out of the driver. (0.333A x 3V = 1W)
The driver will need more than 6V to operate. Two Li-Ions are in the optimal range, so it will get 8.4V when batteries full. 0.333A x 8.4V = 2.7972W going INTO the driver with the batteries full!

This means, the efficiency of a 317 with full Li-Ions is only 35.7%! 64.3% gets converted to heat by the driver, because it has to give the load the same current it is drawing, but at a much lower voltage. As the batteries slowly discharge to 6V, the efficiency slowly climbs to 50%. 50% is still getting converted to heat in the driver.

The average efficiency is ~43%, which means, that only 43% of all the battery capacity ever gets used. The rest is lost as heat.


A good boost driver on the other hand, hardly ever warms up. That's because it doesn't discard excess power, but converts the power into what the load needs. There are some losses in certain components on the driver, and they slightly warm up, but the components never go above 40°C, or feel hot (measured with an IR non contact thermometer).

The efficiency is a pretty constant 84-86%, so the batteries get used to their fullest. Only 14-16% is lost as heat.


Otherwise, i am very flattered, that you people believe, i can make a perpetuum mobile. I wish i could. But i can't..



GamerBR:

GamerBR said:

Or it takes more than 125mA from the battery but the driver only delivers 125mA to the diode?

Click to expand...

Yes. It has to, as the 3.6V battery doesn't have enough voltage for a blu ray diode which needs almost 6V.. The current through the diode is ALWAYS 125mA, be it on a full or completelly empty battery.


Oh, and one important thing. PLEASE don't use the diffraction grating for a few days! Don't take the original lens out! Many people get garbage on the diode window, when they do so, and then make it worse by "cleaning" attempts.

Please make sure you read the cleaning instructions, and otherwise, make sure they are never needed.


Also, PLEASE do NOT atttempt to open the module that is in the head without special instructions! There is an IMPORTANT step to do FIRST!
I can show you pictures of what it looks like, if you're interested. It's much safer than taking it appart.

Re: FS: >110mW Blu-Rays - available

You have the gift to make a small question become a huge answer,but not making the answer boring .About the diffraction grating I must be doing something wrong when putting it,is there any special way to put it on the laser?I'm just removing the original lens and puting in place,I must also use the spring when putting it,right?All I'm getting with the diffraction grating is a huge thin line.

Re: FS: >110mW Blu-Rays - available

Hehehe, that's what you're supposed to get.. ;D
You need smoke or fog to make the effect visible.

A scanner would "wave" the beam left and right, and also draw a line on a wall. Here a lens draws a line, but in both cases you need smoke or fog. You just need to focus it into the thinnest line on the furthest wall first.


And there i was hoping you would listen, and NOT use it just yet...
Please don't get garbage between the lens and the diode. Please?

And if you do get garbage in there, please don't "clean" it.

Re: FS: >110mW Blu-Rays - available

GamerBR said:

You have the gift to make a small question become a huge answer,but not making the answer boring

Click to expand...

Well, i wanted to explain why the current from the battery is different from the current through the diode in this case..

There is no easy way to explain it completelly, other than to explain it completelly...
Someone else may be wondering about the same thing, and hopefully, they will now understand it..



Otherwise, how do you like your laser?

P.S. I ended up keeping the host where the battery is tight for myself.. You can use protected batteries in the host you got. It would prevent them from overdischarging, as i have tested my driver, and it just keeps on working down to 2.2V, and a Li-Ion discharged so low will get damaged quickly.