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Why flashing Laser Died? Answered

I have a laser pointer from the dollar store which I have hacked to fit a usb cord. 3 button batteries came with the laser, so, I figure 4.5v is right. Then I was hacking a magnetic door alarm (siren when the magnet is away from it) Again- 3 batteries, so 4.5 v plus or minus x. The alarm hack is to provide pulsing DC when the magnet is spun in a drill past the reed switch in the alarm.

So, I plugged the laser into the pulsing DC, and it worked for a while, then crapped out.

Why did it die?

slightly different v from different chemistry in the batteries?

or from flashing?

Discussions

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steveastrouk

10 months ago

Laser diodes are "just like" LEDs, only much, much easier to kill with voltage spikes, and overcurrents. Inductive spikes from even the circuit you describe probably did for it.

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caitlinsdad

10 months ago

You might want to try the next one with a capacitor to smooth out the power. The rapid on/off for flashing probably did it in just like you can burn out a lightbulb by playing around with the switch too often.

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Toga_Dancaitlinsdad

Answer 10 months ago

I was using the laser to test the chopped DC for choppyness. So, heheh... Protecting the laser with a cap isn't a priority.

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Toga_Dancaitlinsdad

Answer 10 months ago

Are you implying that laser is still flashing, but I cant tell cause it blinded me?

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Vyger

10 months ago

It was from the dollar store. It was made to self destruct.

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Jack A Lopez

10 months ago

Maybe the reed switch wore out. It is a mechanical thing, and it being in the presence of rapidly changing magnetic field maybe jerked it around too much.

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Toga_DanJack A Lopez

Answer 10 months ago

except the laser no longer worked with a 4.5 v battery

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iceng

10 months ago

I can not find that Following :-((

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iceng

10 months ago

A dollar Chinese laser has an push ON button that I have used so many many times until the battery went dead.. Though I've had units that went dead on the first press..

What I mean is, that is a dollar laser, go buy a few more before you assume the pulsing did it in..

The laser is very carefully current controlled be a resistor (poor design) which suggests that using other batteries with a different internal impedance the laser may get damaged..