268mW 6X Key Chain Blu-ray! (With FlexDrive!) - Awesome!

[IgorT]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

The only thing that worries me is them peeling off at a corner.

A thing like a laser is continuously touched all over. A label has to stay put. But sometimes those warning labels start peling off in a corner (luckily not often).

 

[jayrob]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

They stick really well! Not immediately like the foil warning labels, but give them a day or so, and they stick better than the foil. More durable. No problems with the corners, because they are a little thicker and tougher than the foil labels.

Let me know what you think of the samples I sent you...
Jay

 

[Dark_Horse]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

The battery stack will have to be recharged in the host, but that's not really a problem. The benefits are much greater.. I'd get the runtime of a 10440 laser in keychain form, but protected!

(

Igor, Jay
Could the batteries be charged in the host via a 5v USB-connection? I could mill a tiny pocket for the connector, If there were room.

 

[jayrob]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

That would be sweet if there is room...

I believe that I will most likely stick to the 10280's for my builds, but that depends on what Igor comes up with on this stacked cells! He's got some different hosts that he might have room for a tiny plug somewhere!
Jay

 

[IgorT]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

Socket is one thing. Charge controller is another. I can't fit that in there.

Applying 5V from USB to the stack would make it charge with a too high current, only limited by the protection PCB (if it limits the charging current at all). It might not be too pretty....


At the very least, a Li-Ions needs 4.2V with current limiting applied. Then it charges with a slow topping off..  Often Li-Ion chargers use microprocessors to controll the charging and make sure it's safe.
Protected Li-Ions could be charged with a low constant current. The protection PCB would stop the charging then. But it better work then!

If you simply apply a voltage, then the current will be very high. If that voltage is higher than 4.2V, then the current will still be flowing into the battery above this voltage and it will overcharge.


Those devices that charge from USB, they all have a charger circuit built into the device's circuit. OR the charger circuit is built into the USB cable, in some rare cases.


I can charge Li-Ions directly from my PSU gently and safelly (but ONLY because it has current limiting). But the voltage and current limit have to be set perfectly or it's dangerous!

For charging of the stack to be safe in general use, it would need a dedicated Li-Ion charger with a low charging current...



Anyway, for now, i'll just have a wire at the tailcap, open the tailcap and charge from there..

 

[jayrob]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

Update!

I am very happy to report that my first 'battery current draw' measurements were wrong!

Here are the 'closer' to accurate measurements for the three builds using a fully charged, 200mAh 10280 battery:

* High efficiency PHR-803T blu-ray set at 117mA's and putting out 117mW's. - 175mA's battery current draw. *

* Sony/Senkat SLD1239JL-54 red set at 275mA's and putting out 200mW's. (AR coated lens) - 228mA's battery current draw. *

* High efficiency (freak) 6X blu-ray set at 183mA's and putting out 215mW's! (AixiZ acrylic) - 288mA's battery current draw.

I'm guessing the 6X build will be 30 minutes run time (or less), but who cares?... 215mW's of blu-ray in a Key Chain build!

Explanation:
I found that when measuring current at the negative end of the battery to the host with my DMM, I was getting two different readings depending on which socket I had my positive probe plugged into. I was getting the higher current reading with it plugged into the 400mA max socket. I got the lower reading when plugged into the 10amp socket...

So I asked Igor why, and he explained to me that the DMM gives resistance that is very noticeable with a boost circuit such as the FlexDrive. One socket will give more resistance than the other because one uses a resistor.

Anyway, even with some resistance from the DMM, I am very happy to know that I am still only getting a 288mA battery current draw on the 6X build with the 200mAh 10280 battery! With the boost circuit, the current draw will go up as the battery voltage drops, but this is a good starting point!

Thanks for helping me to understand this Igor...
Jay

 

[nikokapo]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

Wow, dude....wow......This is by far the most attractive solution I've seen to "pocket" lasers. GREAT job.

How do you find the time to do all these projects? Your house must be full of lasers!

 

[IgorT]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

Hehe, no problem Jay, anytime..


Since we talked about this through email, here is a "shortened" version.. Still quite long tho..  :

The current draw will be the lowest, when the keychain build is closed with the tailcap. The tailcap is a massive piece of metal, and if the threads are clean (this is important!), it will provide very little resistance. So whatever you measure, the actual current draw is always a bit lower in a switching driver powered laser...


This happens for the same reason, as the reason why a switching driver will draw more current when the battery voltage drops.

DMMs measure current by measuring voltage across an internal resistor (called "shunt"). Just like we sometimes put a 1 ohm resistor and measure voltage across it.

On top of that, the long wires of the DMM itself introduce a resistane, which the current has to flow through. And all that requires some extra voltage, which is lost, by the time current gets from one probe, through the DMM, to the other probe. This is called a voltage drop, and depends on HOW MUCH current is flowing through a resistance (the higher the current, the higher the voltage drop across a resistance -> U = R x I). If you use a second DMM, you could measure this voltage drop across the first DMM.

So, the DMM introduces a resistance into the system, the resistance causes a voltage drop - the driver gets a bit less voltage than the battery actually has. If a switching driver gets less voltage it will compensate by drawing more current, to keep power (P = U x I) the same. It's the only way it can supply a constant output...


If you would measure the voltage drop across the first DMM with another DMM, you could then calculate how much less the actual current draw in the laser is. But since the 10A (or 20A - whatever the highest) range uses a thick metal rod as a curent measuring shunt, the resistance introduced is small, so the measurement is quite close to the actual current in the build.



The reason this effect is not noticable with linear drivers is, that they draw a constant current (not constant power), as long as they get enough voltage. Putting a DMM in between reduces the voltage the driver gets a bit. But a long as it is still enough, the driver will keep drawing a constant current.

If however, a linear sytem would be barelly above the minimum voltage required for regulation, adding a voltage drop could reduce the voltage to bellow the minimum, and cause the driver to drop out of regulation, while it could still regulate for a while, if there was no DMM in it's way.

At a certain point, a linear driver might still get just enough voltage to regulate when measured through the 20A range, but drop out when measured in 200mA range.


Due to the different behavior of linear drivers, the effects of the voltage drop are harder to notice there, and since this voltage is low, the above situations are unlikelly to happen when testing a linear driver setup.


A situation where the difference in DMM's resistance between the two ranges is very noticable is in the many cheap chinese unregulated green lasers. There, the drivers are out of regulation most of the time, and act as complicated resistors. Measuring the current with the high range on the DMM will show a much higher current than the low range on the DMM!

Another situation is, if you were to make a laser with nothing but a pot between the diode and the driver, set the current with the DMM in-line and then remove it. The actual current in the laser could be so much higher, that it woud kill the diode!

 

[jayrob]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

Wow, dude....wow......This is by far the most attractive solution I've seen to "pocket" lasers. GREAT job.

How do you find the time to do all these projects? Your house must be full of lasers!

Lol! Yeah... I am in my office/laser building room quite often! Sometimes my wife says, 'who are you?' ;D

Thanks for the compliment!
Jay




P.S. Igor, this why I call you 'The Scientist'! Excellent, informative explanation... as always.

 

[danq]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

oops... dumb post...

(or dumb as a post?)

so replacing it with a question: Jay/Igor, what is the final size of the innards of these small builds, after your drill-outs, where controller and battery etc can go - Length x Diameter?

DanQ

 

[jayrob]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

The Key chain hosts that I have from Lowe's, have a little circuit board that the button switch is mounted on. (see first post)

The little spring on this board becomes the positive battery contact point for the laser mod. The I.D. of the host is about 12mm. The length from the spring on the button circuit to the tail cap is 18mm if you cut the tail cap spring a little.

Now if you drill out the tail cap for a longer battery (see first post again), then you can fit a 10280 battery. 10mm X 28mm. You cannot drill out the tail cap larger than about 10.5mm I.D. X 10.5mm depth...
Jay

 

[danq]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

Thanks Jay for answering another pesky question... I'm trying to keep up with this topic because am very interested in tiny builds - but sometimes having trouble summing it all up. Your kind responses much appreciated.

DanQ

 

[jayrob]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

Your very welcome Dan!

Are you kidding? This little build is on my mind a lot these days. I love to talk about it! ...
Jay

 

[Kage]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

Socket is one thing. Charge controller is another. I can't fit that in there.

Applying 5V from USB to the stack would make it charge with a too high current, only limited by the protection PCB (if it limits the charging current at all). It might not be too pretty....


At the very least, a Li-Ions needs 4.2V with current limiting applied. Then it charges with a slow topping off.. Often Li-Ion chargers use microprocessors to controll the charging and make sure it's safe.
Protected Li-Ions could be charged with a low constant current. The protection PCB would stop the charging then. But it better work then!

If you simply apply a voltage, then the current will be very high. If that voltage is higher than 4.2V, then the current will still be flowing into the battery above this voltage and it will overcharge.


Those devices that charge from USB, they all have a charger circuit built into the device's circuit. OR the charger circuit is built into the USB cable, in some rare cases.


I can charge Li-Ions directly from my PSU gently and safelly (but ONLY because it has current limiting). But the voltage and current limit have to be set perfectly or it's dangerous!

For charging of the stack to be safe in general use, it would need a dedicated Li-Ion charger with a low charging current...



Anyway, for now, i'll just have a wire at the tailcap, open the tailcap and charge from there..

Hey Igor,

Let's say you do put a mini USB connector in there. Then take a USB cable and cut it in half and insert a charger PCB out of a DX "DSD" charger in line and put a big piece of HS tubing or something over it. Bingo - you can now safely charge it from USB.

 

[frogger]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

How easy is it to drill out this for an aixiz?
I don't have a lathe or anything, just a drill, dremel, and your standard workbench tools.

And i am looking to do a project with this and, taking advantage of the fact that the batteries can only output a limited current, not use a driver. I have heard that senkat's red diodes aren't a bad choice, but i can't find a number. How much current DO your standard 3 lr44 batteries put out?

 

[jayrob]

Re: 215mW 6X Key Chain Blu-ray! - With FlexDrive!

Trying it without a lathe would be sloppy at best. I guess it could be done by finishing it with a Dremel tool, but it would be very difficult...

I have not tried to power a diode directly from batteries. Only with a dirver. But ask Kenom... From what I understand, he is running his 'Teenie Burner' direct from the batteries...
Jay