How to wake up Rover through acoustic command to Rover Wakey

Set Rover modem register S28=2 so that modem only sets its device enable (DE) line when a specific DE control command is received. In the default state of S28=0, the DE line will be activated for any modem traffic, and we don’t know how many random sounds in the ocean might wake up Rover and waste battery energy.

To set the DE line from the modem deck box on the ship, use the AT$Xn,m (n=modem address, m = device enable state) Remote Device Enable command. The Rover’s LF modem is address 0, and the MF modem is address 3; state 1 activates the DE line, and state 0 deactivates it.

Rover Wakey only looks for an activation of the DE line, and not a deactivation. When Rover is sleeping during a normal mission, the modem will be in a low-power state and the DE line deactivated. When the AT$Xn,1 command is received, Wakey will power up the stack and the Rover will respond to commands.

After waking the Rover with an AT$Xn,1 command, it’s best to send an AT$Xn,0 command to deactivate the DE line. The lithium battery that provides galvanic isolation between the modem and Rover’s stack is drained at a slow rate the whole time that the DE line is activated.

Rover draws 2.5 mA at 30 V when sleeping and not stirring, and 150 uA when sleeping with stirrer controllers unplugged. Stirrer controllers are not sleeping and are always drawing about 1.2 mA each, even when the stir motors aren’t on.

When Rover is asleep and both stirrers are stirring, it draws 36 mA, and 3.6 mA when stirrers are paused for 10 sec.