Arduino Mega Multiple tasks

1 - I have a sound sensor and When there is sound, lights are on! and no problems here..
2 - Theres a bluetooth sensor and its working without problem by itself. I tested it with my arduino, sent and received data without problems.

Note:
This is where the problem occurs!!!

I want to use them together.. Sound sensor and bluetooth together.

When I connect everything, sound sensor starts sending 1 and 0 all the time and lights become on - off and on again. But this starts when i turn on the bluetooth. When i disconnect bluetooth's 5V; sound sensor comes back to normal.

Thank Tou for Your report. As long as Your code is a secret I can only wish You good luck.

Have a look at how the code is organized in Several Things at a Time

Note how each function runs very briefly and returns to loop() so the next one can be called. None of the functions tries to complete a task in one call. And there may be dozens of calls to a function before it is actually time for it to do anything.

...R