PaulS:
{
if (buttonUpState == HIGH && prevBtnUp == LOW)
if (millis() - lastBtnUp > transInt)
channel++;
lastBtnUp = millis();
Serial.println(channel);
}
Curly braces where you don't need them. No curly braces where you should have them. Indenting doesn't mean squat to the compiler. Curly braces do. Use them. Even when you don't think you need to.
PaulS would you please explain what you mean by that? when I add in the { and } before and after the if statements the compiler fails citing the statement "expected primary-expression before '}' token"
I must be misunderstanding what you mean by that.
In response to the use them even when I don't need to, that just causes more problems with compiling as the error message then reads "too many left curly brackets" despite having double checked to make sure I've closed all the open brackets.