Weird driver out of cheap red pointer.

I took apart an old red I had laying around (it was pretty bright), and found a 5.6mm diode in an 8x13mm module with a driver. It was a 3 volt driver, so I hooked it up to a 3.7 volt I scavenged out of an old E-cig (3.746v tested) and a red LED, 2.4v at 80mA. Out of curiosity I hooked it to a blue led and its output changed to 3.6v at 80mA! Anyone have any clue as to what I have? I wish I remembered where I got it so I could buy more.

Anyways I hooked it to a blue test load (3 diodes 1 resistor, right?) for 2.4v terminals, 72.3 mv across resistor, but it outputs 3.6 volts on an led, which has the same voltage as a blu-ray diode right? I think I am gonna use it for a blu-ray laser driver. Oh is it ok to use LEDs as testloads for low powered lasers?

I will post pics of it when I remember my photobucket password.



It is hooked to an IR in the pics, has been hooked to a burner red too, all output is around 80ma no matter voltage output.
Just wanting input before I hook it to one of these sony 150s

I am trying to recycle some of these disposable E-cigs I have, and found I can recharge the batteries, and the metal tubes would make a neat host. They are 8mm ID

Its a constant current driver. Just like every other laser diode driver. Laser diodes need a fixed current power source, or they will try to pull as much current as they can and die. You are reading different voltages because the things you tested pull different voltage.

So it is safe to use with a 150ma Sony diode since it will output the required 3.6 volts, at 80ma only, not overpowering the laser diode?

The only reasons I ask is it is the first true "driver" I have ever seen on a cheap laser, let alone a red pointer from some dollar store. That along with it's size makes it perfect to pair with these (LiPo or LiIon don't know the difference, just batteries in foil with tabs on it, marked 120maH) batteries out of these e-cigs with a very small protection circuit for the batteries, and an 8x12mm housing scavenged from the red plus a tube from the cig makes one small laser.

Oh I figured it was constant current, just curious about voltage, since, again cheap laser pointer.
Ya know, now that I think of it I gave my kids an 80mw laser to play with. thank god the dot was 1/4 inch at 10 feet.

The voltage fluxuates cause thats what a CC driver does, the V out doesnt matter, it maintains the same current level out while allowing voltage to change up or down to match the voltage the diode draws as it changes with temp, also why it works with different color (different vF) LED's at different voltages but always the same vout.

It would be interesting to see some hi-res
pics of both sides of this driver.

jrobertdobson said:

I took apart an old red I had laying around (it was pretty bright), and found a 5.6mm diode in an 8x13mm module with a driver. It was a 3 volt driver, so I hooked it up to a 3.7 volt I scavenged out of an old E-cig (3.746v tested) and a red LED, 2.4v at 80mA.

Click to expand...

It's most likely a linear.

jrobertdobson said:

Out of curiosity I hooked it to a blue led and its output changed to 3.6v at 80mA! Anyone have any clue as to what I have? I wish I remembered where I got it so I could buy more.

Click to expand...

Those are the exact results expected from a
constant current driver. Blue LEDs have a
higher voltage drop than red ones. The
driver will make sure the current stays the
same.

jrobertdobson said:

Anyways I hooked it to a blue test load (3 diodes 1 resistor, right?) for 2.4v terminals, 72.3 mv across resistor, but it outputs 3.6 volts on an led, which has the same voltage as a blu-ray diode right? I think I am gonna use it for a blu-ray laser driver. Oh is it ok to use LEDs as testloads for low powered lasers? It is hooked to an IR in the pics, has been hooked to a burner red too, all output is around 80ma no matter voltage output.

Click to expand...

That is a red test load. A blue diode
would be 6-8 diodes, and a BluRay (Violet)
would be 8-10. LEDs are fine as a test
load as long as the voltage drop is about
the same as the diode you're simulating. I
have also used them for just that purpose.

jrobertdobson said:

Just wanting input before I hook it to one of these sony 150s

Click to expand...

80mA should be fine as long as it is above
threshold. The thing to watch out for is
if the capacitors on the driver will take
the 8.4V from 2 lithium cells. That is
what it will take to drive a 405nm violent
diode.