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ArcticMyst Security by Avery

PHR-803T - Am I running enough current?

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Mar 31, 2009
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built a ddr driver and i think im feeding my phr about 113mA. im using a 9 volt battery right now but once i get jayrobs mxdl and heatsink ill be using 3 10440 batts.
Problem im having is i cant burn anything and cant pop balloons. At first i had a hard time focusing until i made sure and got the diode recessed in the Aixiz far enough but now that thats taken care of, am i running too little current to burn stuff?

phr.jpg
 





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Apr 16, 2009
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Did you actually measure the output current after building the circuit, not just using the simulation? That should be enough current (produces about 150 mW of optical power) but the other thing you might try is messing with the focus, even with an extra magnifying glass or something.
 
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Heh, people end up popping balloons by coloring them black and then focusing down to a point on them. It really isn't all that impressive. You also probably aren't focusing on the same spot very will since it's hard for the eyes to focus that color.

Finally, the laser may not be absorbed very well by whatever you're shining it on. Put your hand in the beam and see if it burns (skin absorbs UV pretty well). It may not have the same response on whatever else you're trying to roast.
 
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Your multisim simulation is not under load. You need to add a load to get an accurate current reading.. Just add the standard test load circuit (4 1n4001 diodes in series with a 1-ohm resistor) to the output of your driver circuit and see if your reading is the same.
 
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chipdouglas said:
I thought it is 6 diodes in series and 1 1ohm resistor for PHR?   ::)


michael
either way works.. all you really need is a load. The number of diodes is inconsequential in this case.. all the diodes do is prevent current from flowing until a certain voltage has been reached..
 
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If you have wired the LM317 as per your drawing (the notations are not standard as written so I may be wrong) you have taken your output from the wrong point so your ma will not be as measured.

Your drawing shows it wired like the bottom left example.

Regards rog8811
 

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ok i wired everything correct. the reason im using multisim is i used my last diode on the DDL Driver. I dont have a test load. I know im getting decent output, the dot is nice and bright.

I figured out the problem im having is focusing. I can get it focused and straight but i cant get a pinpoint dot.
 
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rog8811 said:
If you have wired the LM317 as per your drawing (the notations are not standard as written so I may be wrong) you have taken your output from the wrong point so your ma will not be as measured.

Your drawing shows it wired like the bottom left example.

Regards rog8811

Ok i see what you mean about the leads from the lm317, I drew it wrong on multisim but I wired it correctly.
 
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The difference between in focus and out of focus on a BR is an Nth of a turn of the lens. There are a number of possibilities.

Dirty lens
Dirty LD window
Back hole of lens nut not opened out
LD not in straight
Battery sag when laser running

Are you trying to burn close up as that is the best way to start.

Regards rog8811
 
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Are you using goggles? It'll help you know what's a dot and what's a blob. 405nm light is hard to focus on with your eyes. You should be able to focus to a point; however, the lens is often quite close to the laser diode, so you may need more distance between it and the target than other lasers.
 
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ya i was trying to burn up close and i was able to make a puff of smoke but thats it. my lens is real loose. the slightest touch to the gripper thing makes the beam move and change shape.  Im happy right now with the build.  Have it in jayrob's mxdl build.  I was shining the light on a surface that let me see the dot(my cellphone cover).

lasers.jpg
 
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i want to use the Red/IR diode to make a weak ~10mW dog chasing toy. Whats the best kind if driver circuit to use for a weak laser like that? I plan on using 2 AA batteries to do this. Would the LM317T be a little overkill. Would it be better to just use a diode and cap at this current to drive the diode? Is 3 Volts enough to drive the red laser diode?
 
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Try using some teflon tape on your lens threads to make them grip better.

I wouldn't use anything more than a regular ol' low-power red laser pointer for playing with pets (< 5mW).  It's more than bright enough--you don't want to blind your pet.  My cat didn't even like the < 5mW green laser pointer dot on the floor.

I also wouldn't bother building one, since red laser pointers are so cheap, and already in a nice package.  Just grab one off dealextreme for like $3.
 
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well i have this spare aixiz module and red/ir phr diode left and i want to make it in an altoids can or similar. 5mW is great. whats the best(cheapest) driver i could build for this.
 
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I believe the lm317 ddl circuit is still the cheapest way to go as far a an actual driver costs... however I believe that a phr needs more current than is necessary for 5mw in order for it to start lasing. Its a 60mw diode. Try to stick to the red diode, or just do what the badger says... buy one.
 




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