White Fusion multicolor pot. +cap?

[Pontiacg5]

I sold all my lasers a long while ago to joenobody, a cni style fusion and a black leadlight style pulsar 150. I've been craving lasers again and want to get some again but I'm really interested in a RGV setup.

After looking on the forum I've read that putting a pot on a line with a diode is bad because it could kill the laser if it momentarily slides off the wiper causing the power to fluctuate too much. But what If you put a decent sized capacitor in line after the pot? when you turn the current down the cap should slowly (for a laser I'm hoping) bleed off the extra power without a sudden spike in current to kill the diode. and when you turn the resistance down it would take a fraction of a hundredth of a second to charge the cap back up, hopefully long enough that it doesn't phreak the laser. would this even be possible? I would seriously like a multicolor laser!

Sorry if this has been asked before, I've searched and all I could find was that adjusting a pot on a running laser is bad.

also, do you have to make the white fusion kit yourself, I've got access to a mazak cnc machine if i need to, but i would rather just buy one. is there a website or are they only sold on this forum?

Thanks!

 

[Morgan]

I'll let the electronics experts take up on the pot + cap query but as to the White Fusion Kit...

http://laserpointerforums.com/f64/fs-white-fusion-laser-mixing-kit-42013.html

... also...

http://laserpointerforums.com/f64/fs-full-colour-driver-extension-white-fusion-kit-44052.html

so you won't need a pot + cap!

(Both threads were found in the, 'Pro Shop', section.)

M

 

[charliebruce]

Pot should never be directly in series with the diode - your safest bet would be to use a large potentiometer with no "end" to the wiper track, in series with another resistor, like on the LM317 design, to set the maximum current, then a capacitor across the diode. The reason people say to discharge the cap is that if the diode is removed when running, the driver will normally increase the attempted voltage as high as possible to compensate, thus charging up the capacitor to the driver's max output voltage. Then when you reconnect the diode, the capacitor discharges through the diode directly and kills it. If the driver's current limit is turned down or up by potentiometer, this won't be an issue, since the capacitor hasn't been charged up beyond the voltage the diode is using.