The "Blue Ninja" - 445nm 1,700mW DIY Creation

[HIMNL9]

Re: The "Blue Ninja" - 445nm DIY Creation

Leo:
In theory - would it be any more difficult for an LM317 to deal with a car battery, than with, say, 3x 10440 batteries ?

@rhd
if mean't the higher voltage.. hmm no. Easier to tell you the truth, as some 10440s would not withstand the 1A load and only supply around 600~700mA. The battery car was the only source of power I had :beer:

Uhm, remember that the total heat that the linear drivers (ANY linear driver) need to dissipate, is also given from the difference between the load voltage and the power supply voltage.

I mean, if you have, as example, a LD that require 5V, and you build a linear driver with an LM317 for power it at 1A, then you have 5V (LD) + 2.5V (LM dropout) + 1.25V (Rsense dropout) = 8.75V of total required minimum voltage, for the assembly to work ..... say, 9V, for a bit of margin ..... now, the Rsense dissipate always the same power in heat, if the current don't change, so, 1.25W are from it ..... the regulator need to dissipate all the rest ..... there's a fixed 2.5W from the internal dropout voltage of the regulator itself, that don't change (still at 1A), plus all the rest of the voltage that you need to reduce for regulate the current at 1A ..... with 9V, your chip dissipate 2.75W for 1A, with 12V, your chip dissipate 5.75W, still for 1A .....

So, it's always better to choose the lowest voltage that you need (or the practical one that is the nearest one), for any assembly that uses linear drivers (just for not turn your chip in a frying plate ).

 

[Briellesdaddy09]

Re: The "Blue Ninja" - 445nm DIY Creation

Uhm, remember that the total heat that the linear drivers (ANY linear driver) need to dissipate, is also given from the difference between the load voltage and the power supply voltage.

I mean, if you have, as example, a LD that require 5V, and you build a linear driver with an LM317 for power it at 1A, then you have 5V (LD) + 2.5V (LM dropout) + 1.25V (Rsense dropout) = 8.75V of total required minimum voltage, for the assembly to work ..... say, 9V, for a bit of margin ..... now, the Rsense dissipate always the same power in heat, if the current don't change, so, 1.25W are from it ..... the regulator need to dissipate all the rest ..... there's a fixed 2.5W from the internal dropout voltage of the regulator itself, that don't change (still at 1A), plus all the rest of the voltage that you need to reduce for regulate the current at 1A ..... with 9V, your chip dissipate 2.75W for 1A, with 12V, your chip dissipate 5.75W, still for 1A .....

So, it's always better to choose the lowest voltage that you need (or the practical one that is the nearest one), for any assembly that uses linear drivers (just for not turn your chip in a frying plate ).

I have been unsure what minimum volt i need cause i am using a140 445nm diode & lm317 linear driver

i only had 1/4 watt resistors so i went with 5 in parallel = 1.5ohms which gives me 930ma max. anyways do the extra resistors use any extra volt or not? I came up with around 8-9v so using 3 cr123's would be 9v but wouldn't it fall bellow 9v after a min of use or so? I have been using 4 cr123, bad idea? thank in advance to any input/help received.

 

[Elektrotechniker]

Re: The "Blue Ninja" - 445nm DIY Creation

Adding resistors has the effect to increase needed voltage. Across a resistor we have a vdrop( voltage drop aka V=I*R ) like in every electronic component.

 

[HIMNL9]

Re: The "Blue Ninja" - 445nm DIY Creation

I have been unsure what minimum volt i need cause i am using a140 445nm diode & lm317 linear driver

i only had 1/4 watt resistors so i went with 5 in parallel = 1.5ohms which gives me 930ma max. anyways do the extra resistors use any extra volt or not? I came up with around 8-9v so using 3 cr123's would be 9v but wouldn't it fall bellow 9v after a min of use or so? I have been using 4 cr123, bad idea? thank in advance to any input/help received.

Adding resistors has the effect to increase needed voltage. Across a resistor we have a vdrop( voltage drop aka V=I*R ) like in every electronic component.

If you are speaking about the resistors used for set up the current, then no, it does not increase the needed voltage.

The LM317 keep the current stabilized, regulating the voltage until the drop voltage at the sides of the Rsense is 1.25V, then keeping this value stable ..... so, the dropout on the Rsense is still 1.25V, regardless the current ..... changing the resistance, you change the current that the circuit gives you, not the needed voltage.

Only, try to use resistors of the same (or closest possible) values, cause different values in parallel will dissipate different powers ..... as example, if you use 2 x 3ohm resistors, you have a final 1.5ohm value, that gives you 1.25/1.5=0.833A, and each one of the resistor pass 1.25/3=416mA and dissipate 0.52W (rounding the last decimals )

If you use a 2ohm and a 6ohm resistors in parallel, you still get 1.5ohm, and the current is still 833mA, but the 2ohm resistor pass 1.25/2=625ma and dissipate 0.78W, where the 6ohm resistor pass 208mA and dissipate 0.26W.

Basical ohm laws :beer:

And for the diode, i think 3 Li-Ion cells are enough, cause they are 3.7V each, when charged ..... and 9V are enough for your setup ..... when the batteries go under 3V, the luminosity decrease, bur at this point your cells must be recharged, so 3 of them are ok, for the voltage ..... about the current, it depend from the quality and condition of the batteries.

 

[Briellesdaddy09]

Re: The "Blue Ninja" - 445nm DIY Creation

And for the diode, i think 3 Li-Ion cells are enough, cause they are 3.7V each, when charged ..... and 9V are enough for your setup ..... when the batteries go under 3V, the luminosity decrease, bur at this point your cells must be recharged, so 3 of them are ok, for the voltage ..... about the current, it depend from the quality and condition of the batteries.

Oh i am using Duracell 3v lithium batteries not rechargeable li-ions. So thats why i mean like after a few seconds of use at around 1amp they fall bellow 3volts a piece, so would you say 4 of them would be better. I have checked and after only a few short 10 sec on cycles they are already like 2.7 each.

 

[anselm]

Re: The "Blue Ninja" - 445nm DIY Creation

@rhd:
Epic build! I very much like unconventional hosts and creativity!
How long do the batteries last?

I like how you made the rechargeable without having to remove them.
+1 internets for you (when it lets me)

 

[Elektrotechniker]

Re: The "Blue Ninja" - 445nm DIY Creation

HIMNL9, I was speaking generally, not using regulators specifically.

 

[HIMNL9]

Re: The "Blue Ninja" - 445nm DIY Creation

Oh i am using Duracell 3v lithium batteries not rechargeable li-ions. So thats why i mean like after a few seconds of use at around 1amp they fall bellow 3volts a piece, so would you say 4 of them would be better. I have checked and after only a few short 10 sec on cycles they are already like 2.7 each.

Understood ..... but if you can change your regulator with an LM1117 (not 117), you can still use 3, cause it have a dropout that is around 1.3V, instead 2.5V ..... with the 317, yes, after few minutes the voltage can become insufficent ..... using 4 of them, is ok, you just have more power dissipated in heat frm the regulator, so it need a good heatsink (that from the pic i see you already have), and also a good air circlation around it, for dissipate the heat ..... but yes, it's possible.



@Silvershot: understood, i was thinking you was talking about the current regulation resistors ..... no problems :beer:

 

[Briellesdaddy09]

Re: The "Blue Ninja" - 445nm DIY Creation

thanks for the help guys I appreciate it! just wanted to make sure I wasn't over killing anything...

 

[Leodahsan]

Re: The "Blue Ninja" - 445nm DIY Creation

@Briellesdaddy09
@ 700mA the o-like module goes warm in ~1minute.

 

[Coherent Light]

Re: The "Blue Ninja" - 445nm DIY Creation

@ rhd you're really coming up with some neat builds. Please keep it up as I enjoy your creativity.

 

[danefex]

Re: The "Blue Ninja" - 445nm DIY Creation

Awesome build rhd!!! Love it.... +1 when it lets me again :beer:

 

[rhd]

Re: The "Blue Ninja" - 445nm DIY Creation

@anselm: Not too too long - but as you would imagine, at this power, with such little heatsinking, the duty cycles I put it through are short anyway

@Coherent: Thanks for the kind words!
@danefex: Thank you also for the kind words

 

[LKY2009]

Well done. Small portable Lasers with momentary trigger switches are the best!

 

[Giface]

Re: The "Blue Ninja" - 445nm DIY Creation

I'm using this driver:
http://laserpointerforums.com/f67/c...ff-2x-3-0v-lifepo4-cells-iam-using-59119.html

My experiences on this build have actually led me to question this driver. No doubt it works well for me, but I don't really know WHAT type of driver to classify it as. I really don't like any label that declares it a constant current source. It clearly is NOT, because given the same supply voltage, the output current varried WIDELY depending on the current capabilities of the batteries. IE, 2x 18650s resulted in less output current than 2x Lipos, and more than 2x 16340s.

I understand that this makes sense (IE, if you attached 2 button cells to a driver, we'd expect less output current than 2 18650s). However, it DOES imply the the current limiting function of the driver is not actually supplied by this driver at all, but rather, by the capabilities of the cells themselves.

Which leaves me thinking.... "Isn't this driver more or less just like direct driving???"

rhd, I use that driver in all of my 445 and 405 builds. I made my own boost and/or buck drivers until I found this one for $1.99. I've used at least 6 or 7 of these and have yet to have one fail.

I modify the sense resistor to output from 300mA up to 1.75A, depending on the application. Since the IC on the board is current limited to 2.0A (AX2002), it seems like the sense resistor on your board might be shorted out.

Just a thought.

Dave

 

[Nz Laser]

i want one! im going to create one of these projects once i get the money. I absolutly love the popping speed on balloons jellous