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FrozenGate by Avery

replace 6 AAs with another power source ?,or replace the driver ?

I

infragreen

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hello everyone
I have this DIY LM317T driver , Its working unless there was at least 9 Volts source , that would be 6 AAs batteries , I thought that there were other drivers builds that would defently needs less than that amount of power to work , so can anyone lead me to an appropriate less power consuming driver that I can build ?
thanks
 





Build the same driver, but with an LM1117 or a 1085. The only difference is you'll need to add a parallel input cap as well. Otherwise though, it's exactly the same DIY build that you've already done.
 
Flexdrive V5 is the best driver that can be powered from a single li-ion battery at 3.7V.
Try modwerx.com and cajunlasers.com
They both have pretty good drivers.
But if you want to build the driver you have to use either the LM1117
or the LM108x but with a capacitor at the input as RHD explained.

Jim
 
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Bear in mind that 6 AA cells will realistically never supply the full 9 volts though.

Alkaline cells may be 1.5 volt when they are full and under no or very light load, but as soon as you start to draw current their voltage drops quickly. To get most of the power out of a AA alkaline, your application needs to work down to about 1 volt per cell.

You also use NiMH cells - they start out at about 1.2 volts each, but stay near that voltage until completely empty.
 
thank you guys !! Your reply was most helpful ! , Today or maybe tomorrow I'll go buy an lm1117 , by the way , why would people go with lm317 while we have this one ?
 
What are you powering with the 317? At what current?
2 18650 lithium cells might work...
 
justinjja said:
What are you powering with the 317? At what current?
2 18650 lithium cells might work...
Click to expand...

lpc815 red ld , at ~400 mA

I actually have thought about it , found out that reducing the power consuming might be a smarter option ...
By the way , at what voltage should I run the lm1117 ?
3.7 voltage ? or am I mistaken ? if so , what would be the smallest battery of this kind that can do the work effectively ?
 
sorry , what a noob am I ! , another question , how do I determine the kind and capacitance and voltage of the caps that should be used before the in and out ?
 
infragreen said:
lpc815 red ld , at ~400 mA

I actually have thought about it , found out that reducing the power consuming might be a smarter option ...
By the way , at what voltage should I run the lm1117 ?
3.7 voltage ? or am I mistaken ? if so , what would be the smallest battery of this kind that can do the work effectively ?
Click to expand...

Use two 3.7V Li-Ion batteries with the LM317 or the LM1117.

infragreen said:
sorry , what a noob am I ! , another question , how do I determine the kind and capacitance and voltage of the caps that should be used before the in and out ?
Click to expand...

Read the specsheet of the voltage regulator that you are using, it will tell you what caps to use. ;)
 
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Oh x( me get so frustrated ! , if the lm317 needs as much power as lm1117 why then would I use lm1117 ? , What I am saying is the ld doesn't need more than 3 v ! , I understand that the rest of the voltage goes to regulating the current , but isn't there any other possible way to build one that doesn't need more than 3.7 v ?!
 
Ya,
The spec you are looking for is dropout voltage

your diode needs ~3v and an lm317 in current mode has a dropout of about 4v so you need over 7v or more for it to work

so you either need an ic with a lower dropout voltage.
or you could just buy a driver
aixiz makes one that could run your diode with about 5v
Adjustable current laser diode driver 80-500mA w/TTL | eBay

and if you go to the buy sell section of this forum there are a few other drivers that are probably better
 
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justinjja said:
Ya,
The spec you are looking for is dropout voltage

your diode needs ~3v and an lm317 in current mode has a dropout of about 4v so you need over 7v or more for it to work

so you either need an ic with a lower dropout voltage.
or you could just buy a driver
aixiz makes one that could run your diode with about 5v
Adjustable current laser diode driver 80-500mA w/TTL | eBay

and if you go to the buy sell section of this forum there are a few other drivers that are probably better
Click to expand...
Yeah, the LM1117 has a lower dropout voltage (1.5V) vs LM317 (3V). So I guess technically, you would be able to use 4.5V to power your red with an LM1117 if everything plays nice together. Now if you want to use less voltage on the input, then yes, you're going to need a boost driver.

Welcome to the wild wild world of laser building. ;)
 
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Ghostchrome said:
Yeah, the LM1117 has a lower dropout voltage (1.5V) vs LM317 (3V). So I guess technically, you would be able to use 4.5V to power your red with an LM1117 if everything plays nice together. Now if you want to use less voltage on the input, then yes, you're going to need a boost driver.

Welcome to the wild wild world of laser building. ;)
Click to expand...

I beilieve there is an aditional 1.25v dropout in current mode (correct me if I am wrong, not positive about this)
so you would realistily need 6V with the 117
 
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Ahh yeah, I stand corrected. You'll have a voltage drop from the resistor used for setting the current. :beer:
 
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