homemade 200mw red with module from ebay

[aaron_inc]

hey i am planning to get a laser module like this from ebay
http://cgi.ebay.com.au/200mw-DPSS-Red-Laser-Module-FACTORY-PRICE_W0QQitemZ160054 418590QQihZ006QQcategoryZ14984QQrdZ1QQssPageNameZWD1VQQcmdZViewItem
and im going to put it into a pointer case and power it off two rechargeable cr123a batteries but i was wondering if i could use a 5v regulator to take 6.5v(full) to 5v(empty) and would the voltage stay at 5.0v or would the voltage regulator stop working before the batteries are dead because there is a point where the regulator stops. (i think its called the voltage threshold)

basically i need to get to 5 volts at 230ma anyone got any suggestions?

 

[Apex007]

The link doesn't work for me.

 

[dr_lava]

You should use a LDO (low drop-out) regulator to get the most from your 6.5V batteries. This laser has a regulator in it, but apparently the manufacturer thinks powering it with above 5V will stress it too much.
Shipping is a bit high, don't you think?

 

[aaron_inc]

im in australia so i get cheaper postage heres another link if that one dosent work http://cgi.ebay.com.au/200mw-DPSS-R...ryZ14984QQrdZ1QQssPageNameZWD1VQQcmdZViewItem
i was also wondering if i could use a higher amperage and lower voltage because 230ma X 5v = 1.15 watts so is it possible to run it off nihm aa's (2.4v) instead and have a 480ma of current or will this just blow the diode.

 

[dr_lava]

Well, theoretically you could run it off of 2.4V, and you would proably need a boost switching regulator to get full power. I don't think you really want to get into that.

 

[SenKat]

Expensive shipping yes - but FAST - via DHL - took 2 days to get my Siklaser modules I ordered....awesome modules, too ! I like that vendor, personally - superfast shipping, GREAT product, as well. For portability, check out Glowtorch-touchthesky on ebay as well - nice 200mw handhelds that I tested out to be 237 "ish" on my Coherent lasercheck.

 

[jkaiser3000]

From what little info there is on that auction, I think that diode has its own regulator, so you can use anything between 2.6 and 5.5volts for powering that diode. You should be safe with 3 NiMH batteries.

 

[aaron_inc]

yea but with 3 NiMH batteries the voltage would be 3.6v which is about the same as 1 rcr123a batt but it would bee too big plus i wouldnt be getting full power.
Or did you mean that i could put anywhere between 2.6 and 5.5v and it would be automatically limiting the voltage to whatever it needs?
I rang jaycar yesterday and they have 5v ldo regulators but they have a drop out voltage of 5.5-6v so if they drop out at 6 they could blow the diode so i might need something to cut the power if the voltage reaches 5.5v. this is getting complicated lol.
dr lava could you explain how a boost switching regulator works and where i could find one because i got 4 aa NiMH's with my charger and would like to put them to good use ( im a cheapskate )

 

[dr_lava]

Here's a pretty good runthrough of what a boost regulator is about and how to build one:
http://www.ladyada.net/make/mintyboost/process.html
(I'm basically posting this to inform and dissuade you from doing it at the same time)

 

[aaron_inc]

yes that is pretty complicated is it possible to buy pre-made ones off anyone or is anyone here willing to make me one it i payed them?

 

[jkaiser3000]

As said before, it looks like that module has its own regulator. You supply anything from 2.6 to 5.5volts, and the internal electronic guts will limit the voltage/amps to whatever the diode is comfortable with (according to the manufacturer anyway, I'm pretty sure it can handle a bit more ). In other words, if you use 2.6 volts, you will get the full power from the laser. If you use 5.5 volts, you will still get full power, but it will probably be generating a bit more heat from the regulator. A safe bet would be to use 3-4 volts.

There are several ways to get those voltages, any battery will do, of course. Or, you could use an external regulator, like the lm7805 or lm317. The 7805 will give a constant, regulated 5volts with anything from 9 to 24 volts of input voltage to it. The lm317 is a variable regulator, if you use it apropriately, you can get almost anything from it, up to 37volts, but that's way over the diode's limit of 5.5volts . With these options you're better using a wall wart. I mention this just in case you want a bench top laser (no need to recharge batteries)

 

[jkaiser3000]

oops, sorry, double post (had some problems with my browser)

 

[aaron_inc]

oh sorry i forgot to say that i asked the seller on ebay about the voltage yesterday and they said it would have a different output power if i used 3-4v compared to 5.5v.
yeah it would be nice never having to recharge batteries but i was looking for something portable and pointer sized if i cant fing any way to power it ill settle for 4 aa nimhs and put it in a project box or run if off a power supply.

 

[jkaiser3000]

ohh, I see, sorry, that's why I said "

From what little info there is on that auction

" :laughing:

I'd rather use 3 batteries instead of 4. A fully charged NiMH can put more than 1.2v, I think it's close to 1.4 or 1.5v, I can't remember the exact value, and I'm to lazy to look it up . Better safe than sorry, I'd say