There are two pins associated with the battery monitoring and buzzer functions which are standard on all MultiWii based controllers. These pins can be used simultaneously depending on the setup needed but if no external buzzer is set up, only the LED labeled "LiPo Alarm" will blink when the battery is low. Connect your LiPo battery and buzzer as in the drawing below using the Lynxmotion Quadrino Nano IO wiring harness.
This is a companion discussion topic for the original entry at https://community.robotshop.com/index.php/blog/show/lynxmotion-quadrino-nano-battery-monitoring-amp-alarms