Resetting between projects

Hello all, not sure if this is the most appropriate forum so feel free to move this. As a new arduino user, I have been working thru various simple projects. I will wire one, play with the code a bit then move to the next. After I re-wire everything and plug it back in, it runs the previous code when the power is on. Is there a risk of damaging the uno or connected components from the wrong code? Should I reset the board before disconnecting it when I am done with a project? Thank you, Adam

s there a risk of damaging the uno or connected components from the wrong code?

Yes.

Should I reset the board before disconnecting it when I am done with a project?

No reseting the processor only starts the sketch again. What you need to do is put a blank sketch in it, one with no pinMode() statement in it.

Just something as simple as this before starting something new?

/*
  Blank template that does nothing.
 */

void setup(){
}

void loop(){
}

a_m_922: Just something as simple as this before starting something new?

/*
  Blank template that does nothing.
 */

void setup(){ }

void loop(){ }

Yes, however I usually load the sample blink program when I'm done using an arduino board. That way the next time I power it up and see the pin 13 led blinking I know that it doesn't have some prior project program loaded and running on it. If I don't see pin 13 blinking I know that I should download something to the board before wiring any external components or modules to the board. With a half dozen various arduino boards I have laying about it's important that I try to keep some order in the house. ;)

Make sense?

Lefty