newbie questions about a mod

[LongCoolMother]

hi, i really like this mod i saw here, http://www.moddin.net/article.asp?ArticleID=48 and im interested in trying it. however, ive never modded my case.system besides chaning some LEDS in the cdrives, mouse, keyboards, etc. and i dotn have a dremel. in order to cut the cd im going to need a dremel. i wouldnt like to spend a lot on a dremel since ill only be using it for this mod and maybe some minor ones in the future. will this tool work?



http://www.sears.com/data/product_images/tools/large/00961083000-dlv.jpg

Hand held single speed runs at 35,000 RPM. Comes with 65 accessories and storage case. Has replaceable motor brushes and ball bearing construction.


Great for cutting, grinding, polishing, sharpening and more
Includes grinding or sanding accessory
Perfect for the avid hobbyist or professional




also, in the article, it states that i need resistors. i have no idea how to determine what kind of resistors i need (voltage wise).

and how do i wire up the two LEDs in series? i know they have (-) and (+) wires that need to be wired, but how do i wire them? it looks as if there is only one wire connecting the 2 LEDs in the picture in the article. and how would i connect them to the 4-pin power connectors from my PSU?

thanks a lot. sorry for a whole lot of simple questions.

 

[OulOat]

First, you don't "need" a dremel to cut through the plastic. A hobby knife will do. You want to cut larger than with the dremel so you can sand down the edges. The method would be to, while using a ruler, keep making quick shallow cuts. After a while, turn over and repeat. You would have to keep doing this till 3 sides are cut. The fourth side you can just probably snap off if you cut it up a little.

If you insist on getting a dremel, get another one with variable speed. What they forgot to mention in the article is that the plastic will easily melt if you go too fast. Even using a slow RPM, you should go slowly and let the plastic cool off often.

I don't know which LEDs you are planning to get, but you can always use Ohms law to figure out the resistor needed. Voltage = Current * Resistance. You are probably connecting the LEDs to the 12V line, so 12 / whatever the current requirement of the first LED = the resister needed. Note to keep your units right. It looks like LEDs uses mA (10^-3 Amps). Example: If you decide to get this LED. Using Ohms law. 12V/20mA=600 Ohm resister needed. Don't worry about the second LED because they're connected in series thus they both get the same current.

To connect them both in series, connect the NEGATIVE of the first to the POSITIVE of the second. Repeat if you have more. Then, finally, connect the POSITIVE of the first to 12V line and the NEGATIVE of the last to the ground line. Hope that helps.

 

[LongCoolMother]

thanks, got it. that helped a lot

 

[KouklatheCat]

That tool looks exactly like my old dremel. How much is that tool? Ive used my dremel more then I thought I would. Home Depot has the Dremel for 59.99. It looks like that tool might work but it would be nice to have varyable speed for cutting/sanding different materials.

 

[LongCoolMother]

im wondering, if i wire the LEDs up in a series, do i need the same strength resistor? for example, if i used a 470ohm resistor for 1 LED, would i need only half that value if i were to connect two LEDs on the same series circuit? because it would require more voltage? or do i just stick with the same resistor?