In an emergency, fire alarms are essential tools for protecting people and property. Their main job is to use a loud, obvious sound to warn residents of the presence of fire, smoke, or other hazardous situations. How, though, do fire alarms make this sound? The physics and engineering unde...
It’s good and necessary for a family to learn how to prepare for a fire. Here are some suggestions. Put a smoke alarm in the house. Smoke from a fire causes the alarm to go off. The alarm makes a loud sound. The sound tells everyone to leave the house at once. Make escape(...
It's good and necessary for a family to learn how to prepare for a fire. Here are some suggestions.Put a smoke alarm(报警器) in the house. Smoke from a fire causes the alarm to go off. The alarm makes a loud sound. The sound tells everyone to leave the house at once.Make escape...
All smoke detectors consist of two basic parts: a sensor to sense the smoke and a very loud electronic horn to wake people up. Smoke detectors can run off of a 9-volt battery or 120-volt house current. In this article, we will examine the two most common types of smoke detectors used...
This suggests that somebody has opened a door or window, or made a very loud noise. Some designs utilize the car's built-in stereo speakers as pressure sensors, but others have separate devices that are specifically designed for detection. Perimeter Scanners There are several good ways for a ...
How effective are smoke alarms?Increasing use of smoke alarms is one of the reasons why there's been a long, steady fall in fire deaths over the last four decades since they first became popular. According to the US National Fire Protection Association (NFPA), the fire death rate is over...
For people who are deaf or hard of hearing,it can be difficult to pick out important sounds,such as knocks at the door or fire alarms.Now researchers at the University of Washington have developed a smartwatch app called SoundWatch,which identifies sounds and reminds user...
Alarms and timers you set on your iPhone chime in a loud tone at the designated time. However, in situations such as when you’re in the office or don’t want to disturb people around you, you might want an alarm or timer that doesn’t go off like an emergency siren but rather aler...
We've already seen that the headphones superimpose a reversed version of the drilling noise on top of the original noise, but why doesn't that simply make the noise twice as loud? Soundis energy traveling through the air in waves. Sound waves don't look like the waves on the sea—indeed...
How need to make loud ring tone and silent morning alarm on the iPhone 13 pro .Separate How need to make loud ring tone and silent morning alarm on the iPhone. Separate sound. 1 year ago 352 1 No alarms through Bluetooth headphones I have Aftershokz headphones paired through the Bluetoot...