Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



Laser Pointer Store

Fade on / Current spike limitation

laytor

New member
Joined
Nov 14, 2018
Messages
15
Points
3
Hi , i'm new on this forum , this is my first post , so let's begin (sorry for my bad english .. i'm french ) :

Recently i bought a laser on Ebay , the "Thor M2"(1.3w) it was pretty cool when its was working :cry: ....
After about 2 hours of total usage , the lens just melted and made some ugly patern (plastic lens) , the smoke from the lens got stuck on the actual diode
and the diode was getting less and less bright , so i tried to repair it but ...
jgjhgjh.jpg
I remenbered i was bad af in electronics .
I gave up on this laser .


So i decided to make my own portable laser , the part :

-M140 2W diode (15€) from ebay

-T18 Diode Host + 3 elements lens (5€) from ebay

-XL4015 Driver (CC and CV) (3€) from aliexpress Link

-2xSelf-Locking Switch (1€) (one between the driver and battery , the other between the driver and the diode) from aliexpress

-Case (2€ but dont know if im going to use the one i bought) from aliexpress

-Battery Holder for 2x16340 (2€) from aliexpress


Total : 28€ for a 1.8-2W "Portable" Laser


But there was only one problem , the "current spike" or "Inrush current" on those cheap dc-dc converter , this can burn the diode .
I saw on this thread : LM2596 DC-DC Step Down CC/CV Adjust Power Supply Module

I know that its not exactly the same driver as mine (My driver) , and the thread was made in 2012* ... , but i dont want to burn my diode (even if its only 15€)
I dont have the instrument to test if my XL4015 as a those spike , but just in case .

SO i wanted to know if there is a way and how to remove this current spike and make a "Fade on" ?

Thanks , Théo .
 
Last edited:

Cyparagon

Well-known member
Joined
Sep 12, 2007
Messages
9,601
Points
113
The term to search is "soft start", and isn't necessarily going to help with noise output.

Those won't even fit in your device. You're going to double the size if you ever manage to tame the garbage output. A digital storage oscilloscope and test load would be required to verify any fix that you or anyone else proposed, and given your budget constraints here, that seems out of the question.

Get a proper driver that is known to work with lasers. Keep it simple.
 

Immo1282

Well-known member
LPF Site Supporter
Joined
Sep 4, 2018
Messages
497
Points
63
I'm going to mirror what Cyp has said - Forget that "driver" - it's not designed for laser diodes and will likely have a very poor output performance.

Why spend time, effort and money trying to turn the crappy output from a driver not fit-for-purpose into something that might just about be passable when you could use a trusted driver out of the box that's designed for the task at hand? As Cyp mentioned - for the cost of absolute entry-level test equipment that you would need to check that the output wouldn't immediately kill an LD, you could buy 15 or 20 actual laser diode drivers!

Now I'm not advocating not doing something for the sake of learning - but you will learn plenty building your first laser - so don't feel like you need to reinvent the wheel on day 1 :)
 

laytor

New member
Joined
Nov 14, 2018
Messages
15
Points
3
Thanks for all of you responses , i bought a simple oscilloscope and a current clamp , i will test this driver to see if there is any current spike or anything else , i know i could just buy a x-drive for 38€ and VOILA (the problem is not the money here) , but i wanted to make the cheapest possible 2w blue laser , and simple way to make a "soft start"(thanks Cyparagon) but apparently it would be too big .
I saw this video on YT , this guy used this exact module ,it as the same chip as mine , so there is still something possible c:
 

Immo1282

Well-known member
LPF Site Supporter
Joined
Sep 4, 2018
Messages
497
Points
63
Thanks for all of you responses , i bought a simple oscilloscope and a current clamp , i will test this driver to see if there is any current spike or anything else , i know i could just buy a x-drive for 38€ and VOILA (the problem is not the money here) , but i wanted to make the cheapest possible 2w blue laser , and simple way to make a "soft start"(thanks Cyparagon) but apparently it would be too big .
I saw this video on YT , this guy used this exact module ,it as the same chip as mine , so there is still something possible c:
A current clamp is not quite the right tool unfortunately - as CC drivers with no load will misbehave - and it's risky to test the output on a diode directly, you want an actual test load (You can build one with a wirewound resistor and a few diodes if you want to test lower currents, you'll need to think about heat-sinking for higher powered drivers...). Additionally a proper test-load will let you measure much smaller currents with a higher degree of precision (as you simply measure the voltage across the fixed resistor and even the cheapest voltmeters can measure small numbers of millivolts).

Most soft-start systems operate by ramping the current reference up to the desired point over a set time - and since this is baked into the way the controller for the power supply operates, it's not usually as simple as adding filtering or a few components on the end. Technically you might be able to implement a soft start with a slow low-pass filter on the output, but by doing this you're going to significantly lower the driver's efficiency. Additionally - this approach will do bugger all for the inrush current on the Driver - but would only work to suppress that spike going into the LD.

Are you intending the soft-start to be in the sense of milliseconds (to prevent harsh current spikes but would have no visible fade-on), or a matter of seconds (visible fade-in). The former may be easier to manage with a simple filter - but it's still a poor approach compared to a design where the reference is what is gradually increased.
 

laytor

New member
Joined
Nov 14, 2018
Messages
15
Points
3
I'm not going to directly test the input current on the diode , instead i will use this ( which i already have ) or resistors .
I want a soft-start for milliseconds , just to remove current spikes , i dont really care if it visible or not .
I will recieve my oscilloscope and a current clamp in 2 weeks , so i can post some picture .
 

GSS

Well-known member
Joined
Apr 28, 2015
Messages
3,954
Points
113
Why not just put the new diode with a glass lens in dissasembled Thor you have now using the driver it came with whether it's a cheap driver or not.
Did you destroy it that bad taking it apart?? Unless i'm missing something..:unsure:
Or another Thor with a glass lens for about the same or less the price you are going to invest?
If this is all about learning and doing it yourself project then forgive me;)
 
Last edited:

laytor

New member
Joined
Nov 14, 2018
Messages
15
Points
3
Why not just put the new diode with a glass lens in dissasembled Thor you have now using the driver it came with whether it's a cheap driver or not.
Did you destroy it that bad taking it apart?? Unless i'm missing something..:unsure:
I going to do this with a red oclaro 700mw diode ( cost only 15€) :)
and the Thor driver is dead.
Edit : My plan is to make the cheapest portable ( not really handheld) 2w blue laser .
 
  • Like
Reactions: GSS

GSS

Well-known member
Joined
Apr 28, 2015
Messages
3,954
Points
113
I going to do this with a red oclaro 700mw diode ( cost only 15€) :)
and the Thor driver is dead.
Edit : My plan is to make the cheapest portable ( not really handheld) 2w blue laser .
Hah ha got it:)
 

paul1598419

Well-known member
Joined
Sep 20, 2013
Messages
14,617
Points
113
Don't use the Oclaro 700 mW diode. Use the Mitsubishi ML501P73 500 mW one. It can actually be driven higher than the Oclaro and is far more forgiving too. It is also less expensive.
 

laytor

New member
Joined
Nov 14, 2018
Messages
15
Points
3
Don't use the Oclaro 700 mW diode. Use the Mitsubishi ML501P73 500 mW one. It can actually be driven higher than the Oclaro and is far more forgiving too. It is also less expensive.
Already bought my Oclaro 2 days ago :c , and the Mitsubishi ML501P73 cost 4€ more than a Oclaro HL63193MG (21€ vs 17€)
I think i m still going to buy it xD(because 1.1w OwO)
And i also bought a "16X BDR-209 405nm" 900mw diode for only 20€.
 

Cyparagon

Well-known member
Joined
Sep 12, 2007
Messages
9,601
Points
113
It really annoys me when people start threads like this, then buy seemingly random parts from the internet without asking first. For instance:

i bought a simple oscilloscope and a current clamp
Current clamps (with few exceptions) are AC devices. A laser diode operates on DC.
If you're calling your oscilloscope "simple", I doubt it has the single-shot capture capability of a DSO, which would be required to check the startup behavior.

So you're off to a bad start I'm afraid.

but i wanted to make the cheapest possible 2w blue laser
The cheapest option remains a single dropper resistor for a voltage regulated source like a wall power supply, or the LM317 configured as a current source/sink for unregulated voltage sources like lithium cells.
 

paul1598419

Well-known member
Joined
Sep 20, 2013
Messages
14,617
Points
113
I don't understand why you can't get the ML501P73 cheaper than the Oclaro HL63193MG. They are less expensive most places on eBay here in the US. Be careful driving the Oclaro as they tend to die easily when over driven. The Mits can get you over 1 watt very easily, but I lost two Oclaros trying to get to 1 watt.

I didn't understand why you wanted a current clamp meter either. I have one and it is not good for testing DC current levels. Mine is setup to measure up to 600 amps AC, but won't measure even transients in DC.
 

laytor

New member
Joined
Nov 14, 2018
Messages
15
Points
3
I bought an oscilloscope because i didn't have one , and i will see what the current clamp will do , there is a lot on tutorial on Youtube to use an oscilloscope .

The cheapest oclaro i have found is 15€ , and the cheapest Mitsubisi i have found is 20.5€

I will do some experiment to learn c:
 

Cyparagon

Well-known member
Joined
Sep 12, 2007
Messages
9,601
Points
113
Buy one without understanding specs, "see" what it'll do, watch random youtube tutorials rather than asking for an explanation or recommendation.



I haven't decided yet if I'm impressed or horrified by your recklessness. I suppose there's no real harm in learning the hard way, so long as you're learning.
 




Top