There are many advantages associated with the use of a projection alarm clock. As the name suggests, these types of clock project the time, usually in digital form, onto a wall or ceiling. Most projection alarm clocks have a focus dial to allow you to view the time with extreme clarity, no matter the distance to your wall or ceiling. Many of these clocks also have a rotate dial and invert button.
These allow you to have the projected time at the right angle and direction for you without worrying about having to put the alarm clock in a certain position within the room. I have been using a projection alarm clock for several years now, and find it an invaluable item in my bedroom. Should I wake in the middle of the night, or before the alarm sounds in the morning, I am able to easily ascertain what the time is without having to wake myself up further to look at the small digital display on the base unit. My husband wears contact lenses, and also finds the large projected time on the ceiling above our bed very easy to see. Especially as he would have to find his glasses in order to see the time in a smaller format.
The main advantage of projection alarm clocks is undoubtedly the size of the time projected. It is bright, clear and you always know where it is. The large size (each number projected onto our ceiling is around 40 cm tall) makes it easy to see what the time is without having to wake yourself up to focus on a smaller display.