Error occurs when i use tone in Alarm program

Projects Programming
1

hello im beginner of using arduino and some devices.
im programming simple alarm program for my study
well the program works not bad but when the time i use tone melody example in my program,
something goes wrong

first is one of the button stop working. it reads digital Input but the processes in program dont work
second is I2C lcd displayer shows me a freak words that i never programmed
finally when the program activate tone() it stop working.

the funnest thing is if i dont use the tone and just digitalWrite to use buzzer it works well.

the codes is little bit long to show here so plz visit my github link if u have some time to read it
there is also 3 pictures too.

thanks for reading this and sorry for my suck english

2

tone() is using a Timer2. I suspect that something else in your sketch also wants to use Timer2. If you don't mind waiting for the tone to finish before continuing with your sketch you could just use a loop to set the output pin HIGH and LOW at the frequency you desire.