Circuit and Operation:

Voltage Sensing: Use a voltage divider circuit to scale down the battery voltage to a level that can be read by the microcontroller's analog pins.

Microcontroller Programming: Write code to continuously monitor the battery voltage using the ADC (Analog-to-Digital Converter) pins of the microcontroller.

Alarm System: When the voltage drops below a certain threshold, trigger both the sound alarm (buzzer) and the visual alarm (LEDs). You can vary the alarm intensity based on the severity of the discharge.

Anti-Over-Discharge Protection: Use the microcontroller to control a relay module. When the voltage reaches a critical level, use a transistor to turn off the relay, disconnecting the load from the battery to prevent further discharge.

Diode Protection: Place diodes to protect against reverse voltage and voltage spikes.

Power Supply: Power the microcontroller from a separate, stable power source (not the battery being monitored) to ensure continuous monitoring, even if the battery voltage drops significantly.

User Interface (Optional): Add user interface components such as buttons, an LCD display, or an OLED screen for user interaction, settings adjustment, and status display.

Testing and Calibration: Test your circuit thoroughly using a power supply to simulate different battery voltage levels. Calibrate the thresholds for alarms and protection to match your specific battery and application.

Enclosure and Mounting (Optional): Design an enclosure for your circuit and battery, ensuring proper ventilation for the battery. Securely mount the components.

Documentation and User Manual (Optional): Create a user manual explaining how to set up, use, and troubleshoot the system.