debounce

I am using an EL817S optocoupler to interface a 12 V push-button signal to an ESP32 GPIO. After pressing the button once, the ESP32 GPIO sometimes detects multiple HIGH/LOW transitions. The GPIO is configured with GPIO_INTR_ANYEDGE, so each transition can generate an event. The signal path is...

I'm looking for a circuit whose output stays on for a while after the input has gone, but in negative logic. I know a 555 timer or an RC + transistor circuit works with positive logic, but I don't know what works with negative logic. In other words, a circuit whose output goes LOW as soon as...