standard blu ray driver question

[ashenfang]

hi all. I am a laser noob and have been reading over the forums for the last few hours. I ran across a driver from a member here for use with blu ray diodes. The diode I am using is from a Magnavox Blu Ray player with 3 terminals on it. The circuit is from Daedal. The post is old and the radio shack component numbers are no longer available. But it looks like -

Power supple - 7-8 volts (AA or AAA batts)
LM317 voltage reg.
47uF 35v capacitor
100 ohm pot, but doesn't specify range
2 10 ohm resistors
1n4001 diode
switch

Is that everything? Will this safely and reliably drive any blu ray diode?

Thanks!

 

[GBD]

In general yes, but if you want a lower part count, you can ditch the 100 ohm pot, and the 2 10 ohm resistors, and in thier stead, have a fixed resistor, whos resistance and wattage you can calculate here:

LM317 Current Calculator - Electric Circuit

Note the LM317 is an adjustable regulator, with the pin out such that: ADJ, OUT, IN
the resistor that sets it as a current regulator (as in DDL's circuit) requires a resistance value in between OUT and ADJ.

This is optional, you can stick with the original circuit and part list you said, and it can still work, its just the above method lowers the part count a bit.

also, a 47uF capacitor is a bit overkill for a blu-ray diode, 10uF will suffice.
to further explain, the capacitor's job is to "soft-start" the diode, it also does its job in protecting the diode against spikes.

so in general, this is a nice and simple circuit to get a blu-ray working.

hope that helps out a bit.

 

[ashenfang]

thanks for the reply. since I am a noob at this I don't wanna fry my first diode I just wanted to make sure with this set up, even at its highest settings, it won't fry the diode.

 

[GBD]

Well, I havent yet had a blu-ray diode out of that particular player, so I cant say that the circuit as is wont overdrive it, I drove a PHR-803T diode with this style of circuit, but I used a fixed resistor and drove it at 100mA
but here is what you can do.

find out what is the operating settings, current wise (mA) for your diode.

then type out this desired current range in the calculator I linked you.
that should give you an idea to what resistance/wattage will set your current range that you have.

also, I found blu-ray diodes rather sensative.
for your pot adjustment, Id follow the rule:
set and forget.
even a small spike when the pot "skips" could fry such a diode.

Welcome to LPF btw!

 

[Leodahsan]

AND if you want a smaller circuit you can use a smaller voltage capacitor: bigger than the LM317 voltage output! (mine works with 6.3v cap..)

 

[ashenfang]

you guys are great at answering questions fast! I just placed another order with high tech dealz for the aixiz module to hold the diode.

I see what you are saying about using a fixed output. I guess a POT is nothing more than a variable resistor, so based on what you set the POT at, will determine your final current to the LD, and from what I have read is usually no more than 100mA.

 

[ashenfang]

Ok this is where i get confused. Are all blu ray diodes the same wave length? And capable of popping ballons and lighting matches? Are they all blue in color?

 

[GBD]

Blu-ray diodes are called as such as they are the heart of blu-ray players.

the diode operates at ~405nM, which is a nice violet.
some diodes are capable of higher powers then others. the PS3 sled for example, that can be pushed alot harder then your average PHR-803T diode, but at 100mW, you can still get some burning action if you focus it.

If you want blue, you need to step up to 445nM, which are A-130/140 diodes, not blu-rays, and definatly far higher powers.

 

[Leodahsan]

AND the wavelength can vary: 1nm per 0.8ºC (commonly). it is violet, a high ionizing wavelength, that you can play with GITD objects and light objects. the blue colors diodes are 405nm (5mW to 500mW, in some sleds) and 445nm (200mW to >2.2W in A1*0 diodes). 473 is the prettiest blue but it is DPSS.

hope that helps.