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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?

11 Replies

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steveastrouk (author)2018-03-01

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 (author)2018-03-01

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_Dan (author)caitlinsdad2018-03-02

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_Dan (author)caitlinsdad2018-03-05

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

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Vyger (author)2018-03-05

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

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Jack A Lopez (author)2018-03-01

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_Dan (author)Jack A Lopez2018-03-03

except the laser no longer worked with a 4.5 v battery

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iceng (author)2018-03-01

I can not find that Following :-((

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iceng (author)2018-03-01

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..

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