Schedules Using Sunrise and Sunset

We saw in Schedules and Schedule Blocks that the START TIME and END TIME of a schedule block can be defined as fixed times on the clock each day. We can also define the START TIME and END TIME relative to sunrise and sunset, which the Song Meter Mini Bat 2 calculates each day based on its latitude, longitude, and time zone settings.

This means that, if your goal is to record the dawn chorus each day, the Song Meter Mini Bat 2 can time its recording period to follow sunrise as it shifts earlier and later in the day over the span of weeks and months. This opens up a wide range of useful possibilities for bioacoustics applications.

Let's look at a variation on the single most common recording schedule among users of our ultrasonic bat recorders.

Example: Record Overnight, Plus Some Padding

  • START TIME: Set - 01:30

  • DUTY CYCLE: Always

  • END TIME: Rise + 00:45

The above example is more concise than the one shown in Schedules and Schedule Blocks, as it does not make use of the DUTY CYCLE feature. This schedule block begins 1 hour and 30 minutes before sunset, it ends 45 minutes after sunrise, and it runs uninterrupted for the time in between.

Let's break down the three commands.

Start Time: Offset from Sunset

The first command in this block is:

  • START TIME: Set - 01:30

Set means the START TIME is defined relative to the time of sunset on a given day. The negative sign, -, means the block starts earlier than sunset, and the offset, 01:30, means it starts 1 hour and 30 minutes prior to sunset.

If you want the schedule block to start exactly at sunset, you should set the offset to 00:00. The value of the positive or negative sign does not matter in that case.

Duty Cycle: Always

Setting the DUTY CYCLE to Always means the schedule block runs from the START TIME to the END TIME with no pauses in between.

When Always is selected, the Duty On and Duty Off commands are not used.

End Time: Offset from Sunrise

The last command in this block is:

  • END TIME: Rise + 00:45

The structure of the END TIME command is the same as for the START TIME command. Selecting Rise means we're defining the END TIME for this schedule block relative to the time of sunrise on each day. The positive sign, +, means we want to specify a time after sunrise occurs. 00:45 specifies 45 minutes after sunrise.