I have tried uploading multiple sketches, using tabs in the Arduino IDE, but it keeps coming up with:
Fading_Green.ino: In function 'void setup()':
Fading_Green:16: error: redefinition of 'void setup()'
Decoder_Sketch:34: error: 'void setup()' previously defined here
Fading_Green.ino: In function 'void loop()':
Fading_Green:22: error: redefinition of 'void loop()'
Decoder_Sketch:39: error: 'void loop()' previously defined here
They are in two differnt tabs and I thought that, that would solve it, but it didn't,
Any help with uploading multiple sketches would be great.
One can only upload a single sketch to a arduino board, it's a rule one arduino board, one sketch to run. If you have multiple sketches each with their own setup() and loop() function then you can't combine them by using the tabbed edit windows, as again you can only compile and load one sketch.
What you may want to do is to write one single sketch that performs all the same tasks that the individual sketch tasks did. That would require combining the coding somewhat manually and making sure you don't duplicate function or variable names and don't use the same hardware resources like pin numbers for the different tasks.
I bet this doesn't help?