Notification device, notification method, recording medium, and notification system

1 . A notification device comprising:

an outputter that outputs a sound according to a predetermined condition after outputting notification start information, when the predetermined condition is met;

an obtainer that obtains notification start information output from an other notification device; and

a controller that controls whether to cause the outputter to output the sound, based on timing at which the notification start information from the other notification device is obtained.

2 . The notification device according to claim 1 , wherein

the notification device is communicably connected to a server via a network,

the notification device further includes a receiver that receives a notification instruction from the server, and

the predetermined condition is that the receiver receives the notification instruction.

3 . The notification device according to claim 1 , wherein

when the timing is included in a period before the outputter has output the notification start information, the controller prevents the outputter from outputting the sound.

4 . The notification device according to claim 3 , wherein

when the timing is included in a period before the outputter has output the notification start information, the controller prevents the outputter from outputting the notification start information.

5 . The notification device according to claim 2 , wherein

when the timing is included in a period before the receiver receives the notification instruction, the controller does not receive the notification instruction until a first time period elapses from the timing.

6 . The notification device according to claim 1 , wherein

when the timing is included in a period from when the outputter has output the notification start information until when a second time period elapses, the controller causes the outputter to output the sound.

7 . The notification device according to claim 1 , wherein

when the timing is included in a period after a second time period elapses from when the outputter has output the notification start information, the controller prevents the outputter from outputting the sound.

8 . The notification device according to claim 1 , wherein

the outputter outputs a jingle as the notification start information, and

the obtainer obtains the notification start information from the other notification device by detecting the jingle in a space around the notification device.

9 . A notification method comprising:

starting sound output process, when a predetermined condition is met, the sound output process being outputting a sound according to the predetermined condition after outputting notification start information;

obtaining notification start information output from an other notification device; and

controlling whether to output the sound, based on timing at which the notification start information from the other notification device is obtained.

10 . A non-transitory computer-readable recording medium having recorded thereon a program for causing a computer to execute the notification method according to claim 9 .

11 . A notification system comprising:

a server; and

a first notification device and a second notification device communicably connected to the server, wherein

the first notification device includes:

a first receiver that receives a notification instruction from the server; and

a first outputter that outputs a sound according to the notification instruction received, after outputting notification start information, when the first receiver receives the notification instruction, and

the second notification device includes:

a second receiver that receives the notification instruction from the server;

a second outputter that outputs a sound according to the notification instruction received, when the second receiver receives the notification instruction;

an obtainer that obtains notification start information output from the first notification device; and

a controller that controls whether to cause the second outputter to output the sound, based on timing at which the notification start information from the first notification device is obtained.