Alerting apps can help you be aware of what is going on around you both at home and while out and about. There are apps that alert you to sounds in the environment, for example: an alarm, the doorbell or a telephone. Sounds are picked up by your mobile phone or tablet using its microphone and camera which then alerts you by playing a loud sound, flashing its screen or light, or making the case vibrate.
Other apps are designed to alert you when you receive a phone call, text or email. These alerts will use the phone or tablet's vibrate and flashing functions to let you know when this happens. Some apps can also be used to set a vibrating and flashing alarm.