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FrozenGate by Avery

5mW ghetto supercapacitor cat laser

ilovegm

ilovegm

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Nov 18, 2012
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In the midst of waiting for parts to arrive, I decided to throw together a simple laser just to get over a bad day. Screwed up two exams in a day :banghead:

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Diode came from a "broken" laser pointer, supercapacitor is a 1.5F 5.0V from Cooper Bussman that I had lying around. Excuse the poor soldering, iron is fubar by rust, been meaning to get a new one.

Supercapacitor related:
Charging: Q/Q_max =1-e^(-t/RC)
Energy stored: E=1/2 CV^2

Too lazy to do my calculations so I threw the closest resistor I could find in series with the USB pins and the supercapacitor, this is to stop the cap from shorting your USB port, use any resistance you like, it only affects the charge time as seen in equation above.
Diode already had a surface mounted resistor and it initially took 3.7V~4.5V, good enough. Low end components have the weird ability to take a surprising amount of abuse though.

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I've done this with white LEDs as well, and the diode drains the capacitor much more rapidly than the LEDs.

Aaand... Unfortunately my cats are not of the "laser enthusiast" persuasion. Dammit. :(

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What are you using for current regulation/limiting? I didn't see a driver.
 
I'm using nothing...

Didn't bother, besides, I wouldn't know where to start with making a driver for a capacitor, I mean, the voltage is not constant as it discharges...
 
I like it, ghetto but that was the intent. I can also relate to building lasers n such to relax and get over a bad exam. About how long does the diode keep good power with that capacitor?
 
Try different wavelengths for the cat. I know with my pets, they are kinda "meh" about some wavelengths, but "holy shit I gotta catch that!" About others.
 
A one minute charge yields around 1.5 minutes of good visible laser output, then it continues to spit out progressively dimmer red LED light for another 3-5 minutes.
The exact same build with a white LED has decent output for 20~30 minutes on a one minute charge, not surprising, but the discrepancy was greater than expected.
 
Its cool bro lol

Now I want to do something like this with a crappy little dead cat toy pointer I have stashed lol
 
Well I mean I guess I just need to brush up on my knowledge of what a capacitor is lol. For someone who's hobby is building lasers, I have like no knowledge of electronics haha.
 
A capacitor is basically a battery that is designed to charge and discharge rapidly and many thousands of times. His use of the giant capacitor is basically a quick charge battery.
 
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