How to emulate a 2 AAA battery power.

milkmoth

I have this really cool SkyLaser. It's like a laser pen but it can go for 20 miles.

It takes 2 AAA batteries.

I want to power it with the STAMP breadboard. I got the one they sell at RadioShack. I just wanted to code in cool on/off pulses.

I have a negative lead and a positive. It's just 2 AAA batteries.

How do I make that with my STAMP?

Thanks tons!

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Mike Green

It all depends on how much current your SkyLaser takes. If it's less than 25mA, you can power it from a Stamp I/O pin. If it's greater than 25mA, you'll need a switching transistor that's controlled by a Stamp I/O pin. You'll also need to drop the voltage from roughly 4.3V to the 3.0V provided by a pair of AAA batteries.

Dropping the voltage can be done with two power diodes like the 1N4001 that's sold by RadioShack. Connect the diodes in series, cathode (band) to anode (no band). Connect the cathode of the pair to the positive lead of the SkyLaser. The anode of the pair goes to the positive 4.3V source.

If the current drain is less than 25mA, you can use the Stamp I/O pin to supply the 4.3V (when HIGH).

If the current drain is more than 25mA, refer to Nuts and Volts Column #6 for several possible solutions to providing more current. Click on the main Parallax webpage's Resources tab to find the link to the Nuts and Volts Columns index.

Remember that lasers are DANGEROUS. They can blind people. If you aim a laser beam near an airplane flight path, you can end up in jail.

milkmoth

Holy cow. Thanks Mike. Didn't know you could get in trouble for these things. I was playing with it last night - I just got it yesterday. The darn beam goes straigth up into the clouds making them green! [noparse]:)[/noparse]

Maybe I'll take it to the beach tonight. I originally got it so I could trasmit signals to the space ali*ns in coded trasmissions. [noparse]:o[/noparse])

Thanks for the knowledge.

milkmoth

I'm getting some funny readings from my multimeter. With the laser on with batteries, I am getting 3V. But I am getting over 200mAs. Is that possible? Didn't think it was that much. Any ideas how I can get a 200mA current?


Thanks!

Mike Green

3V x 200mA = 600mW

That seems a little high for what's probably a 50mW laser.

I looked at some of the ads for these lasers. They're selling very very dangerous devices to pretty much anybody and completely minimizing the risks. It is so easy to play around with these devices and just wave the beam around. All you need is just a fraction of a second of the beam reflecting off a piece of metal or broken glass into someone's eyes even hundreds of feet away and you can permanently damage their eyes. They sell these things to burn little holes in plastic bags. It's much much easier to burn holes in retinas in a fraction of the time at greater distances.

milkmoth

They are beautiful when you point them toward the sky though.

But yep, very dangerous.

Redd Dawg

Read this...

http://en.wikipedia.org/wiki/Laser_safety

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Peter KG6LSE

that sounds to Me about right .. I have a 80 mW Out Green that its a 190 IR In to a KTP .

it reads about 270mA ..


the Green ones are NOT rated the same as normal Red ones are . there Pumped ( DPSS) so the Actual IR pumping Laser Diode is often 3 to 4 times the actual output power .
and IR lasers are not 100% Eff .

as for modulation
www.youtube.com/watch?v=J7tXJPkjLGE&feature=related
Green Laser Mod First Light .
Sink it ! Via a MOSFET . I did that with Great results !
http://forums.parallax.com/showthread.php?p=903294


Peter KG6LSE

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