Help me please.........

Hi, I have NEVER made a laser before! Infact I havent made meny technical things before for that matter, but what I wanted to do is make a violet laser. I have a 5mW green laser, a 100mW green laser and a 300mW red. But I have always wanted a blue one and violet is close enufe! Anyway some bloke on eBay is selling a 150mW violet diode and he has put it in a housing (Axixz housing probley )  anyway he was talking about a drive, but I have no idea were to get one. So im just gonna use a resistor. Now im using a 9V battery as sourse voltage. I need 5V for forward voltage and 90mA for forward current. So if im correct, a 47 ohm resister is required. I am also going to add a capacitor(some how  :) And of corse a switch (duh). Can I do this? and how long will it last? And how could I make it, as I dont really know how to add a capacitor to the circut as I have never done it  !  So yea, how long will it last, is it worth it and how do I do it?

You should think about doing what I did, it's easier! And pretty cheap too!

Buy a completed module from Bluray
http://www.laserpointerforums.com/forums/YaBB.pl?num=1224680882

Buy a MXDL, and solder it in. Done!
http://www.laserpointerforums.com/forums/YaBB.pl?num=1226935994 ;D

Searching this forum will yield both complete drivers ready for purchase, and schematics for building your own. I do not recommend using just a resistor and capacitor since this will drastically reduce the life of the diode to possibly just a few seconds or less.

I recommend checking out the sales and group buy sections of the forum, where you will find complete drivers, diodes, and loads of other cool stuff for sale at very reasonable prices..

As far as building your own driver, if you have no experience with building electronic circuits then you'll want to do some reading around the forum, particularly here http://www.laserpointerforums.com/forums/YaBB.pl?num=1185701612, for more info on DIY drivers.