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20x open max driver for 2xAAA source? 555 pulsed..

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Andresc4

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hi all, im new here, im sure that there are similar answers to this, but i need to do a very small driver... i was wondering, there are lots of videos of people connecting a 16x close diode to 2xaaa and they work fine,,, i have a 20x open can, and 2x1,2v 1100ma bateries
i add a cap and a diode in pararel with the sld and for now im using this with 2 almost empty aaa bateries, and it works fine
i want to know what size of resistor i should i add in series ( or pararel ) from the 2.4v to the diode to get a nice output ?
if i dont leave anything in the midle, how much ma will the sled have?

im doing a 555 timer to make a pulsed laser ( not to get more energy, just for fun ), and i also want to add this 555 to a 30mw green, but we can talk abouth this on another thread
 





Re: 20x open max driver for 2xAAA source? 555 puls

That link is for Greg's (Senkat) selling of my drivers... he resells them.  If you'd like to save a little money, click the link in my sig, which is for LPF members.

But, my driver cannot run on 2xAAAs (~3V), they need about 5-6V at least for a red diode. DrLava's flexdrive ( http://www.laserpointerforums.com/forums/YaBB.pl?num=1209418066 ) can run on 2.5-5.5V.

Running a laser diode straight from batteries is a very bad idea, even with a cap and reverse diode on there.  Do a resistor AT LEAST.  But, better yet, use a constant current source, like mine or DrLava's driver, or build one like that in Daedel's post in the Experiments and Modifications forum.

Also a 555 timer will probably not directly drive a diode, and even if it could, you wouldn't want it to as the output will not be clean enough for a laser diode (and probably damage it).  You could use a timer to switch on/off a separate driving circuit, but I don't have a specific example.
 
Re: 20x open max driver for 2xAAA source? 555 puls

If you use a circuit like the flexdrive, the boost chip usually has a shutdown pin that could conceivably be driven by a 555, but you would have to consider reducing the capacitance across the Laser Diode to a fairly small value if you were going to run the 555 at a very high rate. Doing so would make it a little easier to damage the LD if there are noise spikes during power-On, but it could work. Have fun.
 
Re: 20x open max driver for 2xAAA source? 555 puls

i already kill 2 diodes from 2 sony dvds ( they were too hard to remove ) now i found the 20x lg the best opcion to remove the diode, it can pop out very easily, so i dont want to kill this one, it the only one i have now :P

so i will stop runing it straigth from the batteries,,, what size shoud be the resistor ?
i already sent a few pm to drlava to see if he can send me the drivers and a few 808t , so probably next month i have them...

the problem i have with the 555 it the folowing,,, i have the circuit runing, i have my output pin at the frequenzy i want, and a transitor to amplify this output and i have 3v @ 150hz ( perfect square wave )

Kage said:
If you use a circuit like the flexdrive, the boost chip usually has a shutdown pin that could conceivably be driven by a 555, but you would have to consider reducing the capacitance across the Laser Diode to a fairly small value if you were going to run the 555 at a very high rate.
Click to expand...

how do i use this with my diode ? with a red one its easy, i will need to use a smaller cap and a resistor,,, but if i use drlava driver ? i cant power the driver with this output because everytime i disconnect the ic it will start fading up, so i will never get a full power pulse, it will be like a triangular wave, not square. the drlava drive dont seem to have that pin,,, and on the driver of my dx i didt see anything :S

and with my dx30 ? its the same thing,,, and if i disconnect the + from the ld, and i use a transistor as a rele ( using the output from the original driver ) when the transistor its open, the feedback circuit will increse the current becaise the diode will be of, and when the transitor close it will be a hier voltage and it will kill it

adding more power to the feedback pin coud be a solucion ?

 :-?

btw : the little guy we are talking abouth http://www.laserpointerforums.com/forums/YaBB.pl?num=1217996772
 
Re: 20x open max driver for 2xAAA source? 555 puls

I'm not going to recommend a resistor... I'm going to recommend a proper driver, which I already have given examples for in my previous post.

If you want modulation, as DrLava about his Flexdrive Mod, which has TTL option. You could probaby then drive the TTL input with the 555, as long as it produces enough voltage.
 
Re: 20x open max driver for 2xAAA source? 555 puls

ohh i didnt know that he have that mod, i will ask him

and i can run this dx30 with that driver, how much power do this ir diode need ?

you solve my problem ;) , tnks
 
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