My first 405nm pointer (190mw)

[andy_con]

this is my first blu-ray pointer build, its in a leadlight case.

yesterday it was only outputting 100mw today, once in the case and all finished its hitting 190mw?????

so gota stick to a strict duty cycle

just need to add one of my warning labels now

 

[el-taco]

Looks great in that case.

190mW? Damn...

 

[andy_con]

yeah but 190mw isnt good, it has a duty cycle of like 20seconds on and 20 seconds off

sadly ive glued it all in so cant really take it out again now

 

[andy_con]

the blu-ray diode is amazing!!!

it stays at 190mw no matter how hot it gets! at 40seconds you can feel the end of the pointer is pretty warm and its still 190mw

the beam spec of 405nm is pretty dam impressive to.

both my home made 230mw red and 190mw blu-ray at 18-20metres

 

[IgorT]

yesterday it was only outputting 100mw today, once in the case and all finished its hitting 190mw?????

Is it possible, that you shorted something there, once it was inside the body? Or could the pot have turned?

What is weird, is that the power doesn't drop with heat. With constant current it should drop, as the driver decreases the voltage, and the efficiency goes down. The only case where i saw power stay the same for a while was with constant voltage, where the current goes up with heat. But even then not for long..  :-?


There is one thing you can do. Measure the current draw from the batteries, and their combined voltage (you probably can't measure voltage under load?). It won't even be close to exact, but it would show if the output current is twice to high. And it would have be almost twice too high to reach 190mW, compared to 100mW....

 

[GooeyGus]

Which diode is it? PHR-803T or the 6x?

 

[IgorT]

If you click on the link in the sig, it says it's a PHR.

 

[andy_con]

i did damage the driver and had to doa bit of reworking. i thnk i connected everything up right.

sadly as everything is glued into the pointer i cant measure anything.

im going to keep this laser so it isnt a problem ill just stick to a good duty cycle.

is interesting that the diode does not seem to drop in power though

 

[laserfreak3d]

nice job on that pointer mate looking great 190 mw is realy awesome

 

[andy_con]

cheers martijn, i was trying to get hold of you last night to show you, but guessing you wernt there.

yeah 190mw is a little over powered but its fine just for me to use.

we need to get some 300mw red up and running mate

 

[IgorT]

sadly as everything is glued into the pointer i cant measure anything.

Well, that is not completelly true. As i said above, you can still measure the current draw from the battery. Just replace the tailcap with your DMM in the highest current range.
Then take batteries out and measure their voltage. (make sure you don't forget to change the socket, or you'll short them.... )

If you do this, i could at least approximatelly tell you the current through the diode..


But if you damaged the driver, did you not set or at least test the current again after that?


Otherwise, i had 195mW once.. It was pretty.. Lasted for a week. Now, 120mW just won't do anymore...

 

[andy_con]

ok im going away today but when i get back ill see what i can do.

if it only lasts a week then so be it LOL

 

[IgorT]

Well, but i do run them around 60 minutes a day, so... It could last longer, if you use it less..


But i'm worried, that you somehow messed up the regulation, and it's now boosting to the max the IC allows (6V i think?). This would explain the power not dropping - the current would climb with heat (the diode internal resistance dropping).

If so it could also suffer thermal runaway.


But that's why i'm interested in the current. Make sure you measure it before it dies. Cos even if it is still constant current, the current draw from the battery will change after the diode dies - the Vf drops to around 3V, and the driver has to boost less high.


BTW: Did you sand a trace away, when making it smaller? Or a via? Is that red wire connecting the two sides?

 

[andy_con]

well i didnt use sand paper i used wire cutter to shave the edges.

but yeah i took out a track, so the red wire is in its place

lucky im good a soldering, i use to change leds in mobiles phones, so im pretty good at small stuff

 

[IgorT]

Strange, that it's acting up..

Anyway, when you get a chance, i would be very interested in the current draw.