I've a 555 timer in monostable mode connected to a momentary push button. My goal here is to power the circuit, and then press a button that will start the 555 timer for 10 seconds, then completely stop, until the button is re-pressed.
I've tried making a prototype on Tinkercad, and it works well. However, the LED always turns on for 10 seconds without pressing the button.


I've tried many solution I've seen here, but none worked.
Here's the schematic:

 

Try connecting the Reset pin to Batt+ via 10k and to Batt- via 0.1uF. (These values aren't critical).

 

However, the LED always turns on for 10 seconds without pressing the button.

I assume this occurs during power up(?).
If so, try connecting C1 from pin to Bat1+ instead of BAT1- (C1 plus to BAT1+ and C1 minus to U1 THR and DIS), if you haven't already tried that.


P.S. Please learn to draw schematics in a more standard manner with the passive parts close to the associated IC and with a vertical orientation, rather than the spread-out, difficult to read layout you did (example below):

 

I assume this occurs during power up(?).
If so, try connecting C1 from pin to Bat1+ instead of BAT1- (C1 plus to BAT1+ and C1 minus to U1 THR and DIS), if you haven't already tried that.


P.S. Please learn to draw schematics in a more standard manner with the passive parts close to the associated IC and with a vertical orientation, rather than the spread-out, difficult to read layout you did (example below):

View attachment 325847

Woah, thanks so much!! It works flawlessly. I've been having trouble for like 5 hours.
Would you mind telling me what was the problem?

 

The power-up state of a 555 can trigger the one-shot, which then charges up C1 until the THR voltage is reached (2/3 of V+), resetting the 555 and terminating the pulse.
Connecting C1 to V+ means the THR voltage will go high through the capacitor as power is applied, thus insuring that the 555 is reset to zero out.

 

Would you mind telling me what was the problem?

It's typical to include a power on reset functionality if you care about how the circuit behaves when power is applied. By holding the reset pin LOW during power on, the timer can't see a false trigger.

Your schematic drawing style is not useful for communicating circuit intent. The symbol Tinkercad uses doesn't help because it was created without any thought about how a 555 is used. Someone had to put effort into that dumb symbol because it isn't the also useless pin order symbol.

What you drew after removing unnecessary white space and colors:

Drawn more conventionally with a better timer symbol:

I modified the symbol Eagle had because it was also created thoughtlessly.

press a button that will start the 555 timer for 10 seconds

Your circuit isn't a 10s timer. It's 550ms (did the calculation in my head). 50uF isn't a standard value anyway.

 

Try connecting the Reset pin to Batt+ via 10k and to Batt- via 0.1uF. (These values aren't critical).

They somewhat are, as the Reset pin has to be held below about 0.6V during the time it takes the power to come up.

 

They somewhat are

Ok, I accept that they need to be in the right ball-park.