I have an arduino uno
this is the scheme
My LCD I2C blinks like (it's losing voltage) when the buzzer it's activated. the buzzer does a beep beep sound and my LCD blinks at the same time. it also makes the LCD lose contrast over time and i have to regulate again until it's a max power, once it hapen, i need to dissconect and leave it 5 minutes like "cooling down".
I was thinking maybe the battery, i'ts new but can be faulty.
Anybody knows why can be happening?
Where you found this schematic?
Why analog ports are connected to ground?
I do this scheme in power point sorry
Analog inputs are connected to ground because they are pulled_up, this is a bomb simulation game and the objective it's to cut the wires
Which type of battery are you using?
9V battery
What's the maximum current of this buzzer?
Maybe a transistor is needed to control the buzzer.
That simply doesn't make any sense at all. Once you connect any pin to ground, no amount of pulling up is going to shift the pin. It is at ground.
You have no battery on that layout diagram (it is not a schematic), so where is it?
What sort of battery do you have?
Not faulty as such but you could be drawing too much current out of it and it has now nearly empty. Your symptoms match a discharged batteries slowly recovering over time.
What do you see when you measure the voltage from the battery when you are running your code?
One of those that is used in fire alarms, is useless for Arduino projects.
It makes sense if you think that this wires are 4 pressed buttons.
That's the point
What happens when the board is powered with 9 V power adapter?
No it doesn't.
However it makes sense if it is these wires to ground are the ones you are hoping to cut.
6.5V but it goes 6.1 some times
We don't know the code.
Likely overloading the battery, it's output will sag as you're experiencing, and recover(somewhat) when load is removed. Get a decent wall-wart - make sure it's regulated, not a piece of junk. Rating should be between 7 and 10 V, at least 1-2 amperes, because your next project will likely want even more current than this one, may as well be prepared.
tipical small, black, cilindrical, active buzzer
That is not enough to drive an Arduino through the Vin or the barrel connector.
It is supposed to be a 9V battery. It is flat.
Use 6 AA batteries in a pack for a better battery life.
It doesn't say what's the current pulled from digital pin.
it needs to be a battery
Then get a bigger battery, because a smoke alarm battery is just not worth the pain. Look under the hood of your car.
FWIW, I find it useful to use a wall supply for all development, regardless of whether my target is wall-free or not. Reduces the number of error sources. When I finally change to a battery, I can focus on whether that contributes a problem or not, knowing the project works fine on a power supply. But hey, it's up to you.