Rapidly spinning laser to create one-lined image

Grumpy_Mike:

(assuming the voltage is not more than the required amount for the laser)?

Hint:- it is.

If the laser wants 3v, then I just add the appropriate resistor right? Problem solved. Is there something I'm missing or is it not that simple? If I am missing something, why can't it be mentioned in one or 2 sentences? Like this, "That won't work because X, Y, Z"