IR 5' sensor Power question

I peeked at another thread that made me wonder:

If I have one IR 5' sensor, then it *should* work off the MC using my USB for power, but if I have 4 of them, it won't work?

Right now my single sensor is being a bit stubborn. Should I spring for a 5V adapter and thus solve the possible power dilemma which might be why my single IR sensor is not responding? I see a hint of glowing red, so it's getting some power... perhaps just not enough to work well, yes?

Thanks guys.

Roz

errr.... I should amend that post for clarity:

I have one IR sensor working but wondering if 4 is "three too many".

simple patch, was uber easy (just checking /analogin/0/value with Metro 100)... hence just need advice re: power question.

thanks, see ya in the morning.

Roz