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FrozenGate by Avery

Low Power Usage?






Why would you go to all that trouble.....:thinking:

Just build an LM317 Current Driver (DDL) and turn it down to
the Power Level you want...

The 445nm LD starts to lase at about 210mA to 220Ma and the
output when it starts lasing is about 7mW...

That information is posted on the 445nm Data/Power threads...:cool:

Jerry
 
I know, but there is the problem, that its not stable at threshold.

Some one here said it changes with rising/falling temperature, so i have fear, that what was 7mW at room temperature will be 200mW outside oO
 
Why not use a µC? They have guaranteed fast PWM.... you just need a good driver that supports TTL, and a bit of space to stick the µC. If you're using a single li-ion battery, you can just drive the µC straight from the battery. On top of that, you could easily do power shifting with memory. So you could do something like 10-40-100 percent power by pressing the switch.
 
Arent µC's to fat to fit there, or do you mean bga-types?
will be tricky to solder. and to programm the "modes" :D
 
Xer0 said:
Arent µC's to fat to fit there, or do you mean bga-types?
will be tricky to solder. and to programm the "modes" :D
Click to expand...
All of our drivers are already SMDs, we might as well add a few surface mount SMD µCs, those things are TINY (but large enough to hand solder if you REALLY wanted to lol)! The only external component you need is a resistor (you don't need a resistor if you don't want it user-programmable). I don't think they even make BGA 8-bit microcontrollers, there's no need lol.
 
Ok i now would just throw money at it and search for a complete Unit!

Have a thread in the BST section, please look :)
 
How weak are you wanting it? Like was said before, just set it to something stable, but low. Then use almost black glass (or ND filter). that should be the cheapest option.
Not to mention looking neat. Just black "looking" glass with a beam magically shooting out of it. You can have the first iLaser
 
You could construct a PWM circuit out of a 555 timer.

I would not use a ND or filter window to limit the power of your laser unless it is at very low power levels and a high quality filter that will not bleach over long periods, and not reflect the beam back into your diode. Many filters are simply not designed for prolonged exposure by laser light. If you still want to try it, for a cheaper filter you could buy a ND filter for a camera and then do some glass cutting on it to shape it down to size. They can cost down to $15.

Still, you'll want to get the laser power as low as possible with a driver anyway.
 
Yeah i saw the Camera filters at DX for some bucks. would neet to put them at 45° or, to not damage the diode with reflections?

I want it at max 50mW, better 15-25...
 
The new Microboost supports PWM. Set it at a sensible output and PWM drive it.

M
:)
 
Xer0 said:
Im always reading here about the Laser' behaviour at the Threshold current. that it can jump from LED to dangerous in just smallest turns of the pot. and even badder, with rising temperature it drifts.

Is there actually a chance to make this Diode stable at low powers?
I want a reasonable pointer, expecting 5-15mW. 50mW would be the absolute max i take!

Idea: setting it at 100mW and putting an OD2 in front, so -> 10mW. Will the filter sustand the 90mW it must dissipate for longer time?
Click to expand...

Not for these laser diodes. They actually start lasing at 230mA-240mA @ ~4-5v. I did some tests last night after messing with one of my OEM drivers. It was a 180-400mA 3.2-5v driver. I had the pot turned down all the way using 4.6v and the diode refused to lase properly and actually sputtered, kind of like a car trying to start on a cold day. it just sat there and gave a blue LED light that seemed to pulse trying despirately to lase properly. As soon as I re-adjusted the pot for ~235-250mA ballpark the blue light became a beam. At
400-405mA the beam was powerful enough to punch a hole in dark coloured box 15ft away partially-unfocussed.

Sorry 445nm aint a low powered diode. It is a diode that operates nominally at 400mW-1.3W. These aren't for you. Why not go with a PHR blu-ray?
 
Seoul_lasers said:
Sorry 445nm aint a low powered diode. It is a diode that operates nominally at 400mW-1.3W. These aren't for you. Why not go with a PHR blu-ray?
Click to expand...
Cuz i have lots of Bluray, and with 445nm, they got boring ;)
A visible blue beam and spot on every surface, not only fluorescing ones.
 
Geez, my diode operates perfectly fine at just a few mW, just a tiny bit above threshold. If your testing driver isn't precise enough to actually find the threshold, then yeah, it'll go straight from nothing to a lot. but I can turn my pot up slowly and very easily find a nice place with a nice, low power dot on the wall that doesn't need glasses. I believe Lasersbee was also able to get his running at a nice, consistent 7mW with nothing extra beyond a constant-current driver.

Seriously, hook up an LM317 driver, with a pot in series with a resistor (the series resistor sets max current so that it's safe to turn the pot, as the series resistor limits the maximum current to the diode), and turn the pot slowly. I found it very easy to get a nice low power dot out of the thing, nice and stable, and certainly not dangerous at a low power.

Before you go through all the PWM trouble or just give up, try running it at low power! It's perfectly possible, and easy, despite what some people believe. You may not be able to get it too stable at 1mW, but surely 5 or 10mW is ok for you, no?

As far as threshold temperature instability, there is a very easy way to measure the characteristic temperature. I don't believe the temperature dependence will matter that much in just going from inside to outside or anything like that, but if you feel strongly about it and don't want the trouble to measure the temperature dependence, it's very easy to make sure you're not unsafe. Simply, the threshold current rises as temperature increases. Therefore, assuming you set your current so that it is always lasing at all temperatures, the laser will put out more power at the same current as the temperature decreases. Therefore, if you set your current in the coldest environment that you plan to use your laser in, the output power will never get higher than that. As long as it still lases in the hottest environment, you're all set.
 
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So you mean, all i need for a pointer is a Microboost or Flexdrive, and i desolder its original pot, and replace it with a 25-turn one; plus a resistor in series, for setting current to max? (in the fridge, as winter)
 
pullbangdead said:
Geez, my diode operates perfectly fine at just a few mW, just a tiny bit above threshold. If your testing driver isn't precise enough to actually find the threshold, then yeah, it'll go straight from nothing to a lot. but I can turn my pot up slowly and very easily find a nice place with a nice, low power dot on the wall that doesn't need glasses. I believe Lasersbee was also able to get his running at a nice, consistent 7mW with nothing extra beyond a constant-current driver.

Seriously, hook up an LM317 driver, with a pot in series with a resistor (the series resistor sets max current so that it's safe to turn the pot, as the series resistor limits the maximum current to the diode), and turn the pot slowly. I found it very easy to get a nice low power dot out of the thing, nice and stable, and certainly not dangerous at a low power.

Before you go through all the PWM trouble or just give up, try running it at low power! It's perfectly possible, and easy, despite what some people believe. You may not be able to get it too stable at 1mW, but surely 5 or 10mW is ok for you, no?

As far as threshold temperature instability, there is a very easy way to measure the characteristic temperature. I don't believe the temperature dependence will matter that much in just going from inside to outside or anything like that, but if you feel strongly about it and don't want the trouble to measure the temperature dependence, it's very easy to make sure you're not unsafe. Simply, the threshold current rises as temperature increases. Therefore, assuming you set your current so that it is always lasing at all temperatures, the laser will put out more power at the same current as the temperature decreases. Therefore, if you set your current in the coldest environment that you plan to use your laser in, the output power will never get higher than that. As long as it still lases in the hottest environment, you're all set.
Click to expand...

Yeah, you're right... it's the driver, but at those low powers I have noticed (on my 90-200mA driver) you can't get the full diode powered and the output doesn't look very multimode.. weird stuff. The weakest beam is probably 100mW I can manage without sputtering on the high power module. still plenty hot enough to smoke dark coloured materials.
driver consumes a lot of current and seems like it's fighting the diode for current.

I am replacing this driver with a Die4lasers 445nm addition driver.
 
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