Why your circuit does not work? Because the battery is run out. These low voltage indicator circuits may helpful for you. If you can know before and change a new one right now. It makes you not have to waste time when using those projects.
The simple low voltage tester circuit using LM339,can use Battery voltage monitor for voltage sources that problems, by LED display and alarm sound.
This fine 1.5V battery tester circuit using LM324, Can measure the voltage of the 1.5V battery AA or AAA. As decimal point. Easy to use by LEDs display