L.E.D.'s and lasers?

Well you got a lot of random answers, didn't you? Let me give it a shot, and I will even try to answer some of your questions! You can get laser diodes at some electronics suppliers (things like digikey, etc). (By the way, the difference between and LED and a laser diodes is basically that the laser diode has polished ends. The device is actually very similar, but the laser makes a build-up cavity to better control the emission properties.) I think you would be better served just buying a laser pointer, because the electronics for controlling laser diode are not trivial and you will spend a lot of money making something that works no better than a laser pointer that you could have bought for much less.

You say you want a 10 or 15mW laser. You should be warned that anything over 5mW is not safe because it can cause eye damage faster than you can blink. If your goal is to zip the beam around the room on a rotating mirror, that is hardly a safe situation. Professional devices that use more than 5mW have very strict safety requirements and need to be mounted in such a way that they could never possibly shine into someone's eyes. You would be much better off sticking to something under 5mW so you don't end up blinding yourself or someone else. And make sure you stick to something between 400 and 750 nm. Anything outside of that range is not visible to the human eye (and more dangerous to people's vision!)

I am not sure what you mean by a LED light bulb. If you are talking about the thing that you screw into a light socket to replace your reading light, then that should be able to plug straight into a regular light socket and all the resistors should be taken care of. If by LED light bulb you mean the little colored things (which are just called LEDs), then you do need to have a resistor in there. The reason is not the bulb is going to poo. The reason is that LEDs (and laser diodes) are very sensitive and fragile. A slight over voltage can burn them out, while an under voltage will not make them light up. So what you need to do is figure out the specific voltage and current requirements for the LED you want to use. These parameters are not the same for all LEDs, so you will need to check for each different type you want to use. Then you need to figure out what your supply voltage and current are. Once you know these different numbers, you can design a voltage divider using resistors that will take the high voltage and reduce it to the proper voltage for your LED. Generally the circuit you will need will look like a resistor in series with a resistor and LED in parallel. The first resistor acts as the divider to cut the incoming voltage while the second resistor (the one in parallel) regulates the current in the LED. If you are using an AC voltage as a source, the situation is a bit more complicated. You can use the alternating voltage directly if you want to, but make sure the peak voltage is what you are cutting down to the correct voltage, NOT the RMS voltage. Some LEDs can be damaged by the negative voltage, so make sure yours can't. Alternately, you can rectify the AC voltage, which will keep it from going negative and will make the LED brighter, since the voltage spends more time in the correct range. But, in general, if you don't know enough about circuits to understand what I have said, then you should consider buying something that already has working LEDs.

actually there are laser diodes, they are inside cd players, dvds, but those are dangerous if the light hits your eyes. the resistor is to set the amount of current and the value is determined by using ohms law E=IxR where E represents the voltage, I represents the current, and R represents the resistance. when you buy a laser diode it will have a data sheet or you can look it up by the number of the diode to find out how much current it requires and its maximum current it can handle. It just depends on which diodes you use.laser diodes are also used for fiber optic networks.

you can look this project up online, my friends actually wants to do it, and is probably gonna once he gets he money. you need a 16x cd drive a normal size maglight that takes 2 AA batteries, and a laser housing thats like 30-40 bucks, and a soldering iron. when your done and use a 16x speed laser can light stuff on fire/burn stuff from about 2-3 meters out. so its pretty good for messing with people (cutting backpack straps, tattooing phallic symbols on people you dont like's backs, etc.) but all in all it will probly end up costing you around 80 dollars. and dont listen to the spoil sports, this is the only fun thing our generation has left to do with all this parental/govt over look bullshit. look up laser hack or maglight laser on youtube or use the site below, have fun and for the record if you blind yourself with a laser you deserve it

LOL, you cannot make laser out of L.E.D. Totally different physics behind it.

LED's are not lasers. Not even close.