Vaupell:
Well an old post, and it seems to be a common problem..For future reference
Often the problem is cheap shit from a company called "keyes" they
produce a ton of crabby sensors and other stuff to sell to new players..I once had a similar problem, i solved it by using a old TV-Remote.
Using a high quality remote like the ones that comes with your TV, ensures a steady, constant ir signal.Where the cheap ones can change value, depending on the angle between the receiver and sender.
...Use a program to read your TV remote keys and then reprogram your software to use it.
So the problem was with crappy sensors from Keyes, but you solved the problem by not replacing the sensor, but a different transmitter.. That doesn't make sense.