User manual

U-Ground User Manual - Alarms

4.1

Audible Signal

Besides toggling the corresponding line, the ground station will generate a square wave to be

feed into a square wave buzzer.

The audible tone generated at the time of writing (2014/09/03) are 3 beeps of half a second

duration and variable pitch in function of the toggled alarm.

An audible tone will be generated any time an alarms goes from deactivated to active. If more

than one alarm is triggered at the same time, the ground station will generate tones for every

one of the alarms in a sequential manner.

Audible tone is designed to be used as an addition to a visual feedback mechanism: Audible

tone attracts the attention of the operator and he checks the visual feedback panel.

Again, U-Ground will drive at most 25 mA at 3.3V TTL. As this is usually too weak to drive a

buzzer with enough power to be clearly audible, a MOSFET drive would be recommended for

the buzzer.