Doubt about laser power in laser transmitter

[NOMI_2009]

I'm making a laser torch based audio transmitter n receiver using 2n5777 phototransistor as receiver what must be the min power of the torch

 

[Wetmelon]

How far are you shooting this laser? .5 inch? a foot? a hundred yards? 20 miles? This will affect your required strength

 

[NOMI_2009]

range is about .5 inch

 

[BenchTop]

If you are running a laser diode with enough current so you can see it yourself, you will should be able to detect it with almost any photodiode 100 meters away in decent conditions, easy!

 

[skeptic2]

Now would be a good time to learn about link budgets
http://en.wikipedia.org/wiki/Link_budget