Some clocks, usually digital ones, include an optical projector that shines a magnified image of the time display onto a screen or onto a surface such as an indoor ceiling or wall. The digits are large enough to be easily read, without using glasses, by persons with moderately imperfect vision, so the clocks are convenient for use in their bedrooms. Usually, the timekeeping circuitry has a battery as a backup source for an uninterrupted power supply to keep the clock on time, while the projection light only works when the unit is connected to an A.C. supply. Completely battery-powered portable versions resembling flashlights are also available.
"love it...Not bad...The alarm clock is one of the best I have had, the kids enjoy the extra interactions, and having music anywhere without having to connect my phone to a speaker has been wonderful....I just broadcast a message to them and a glass of water appears in my room LOL I like that it can be controlled from the clock or my phone, so no matter when I am I can broadcast or turn their music down"
The word horologia (from the Greek ὥρα, hour, and λέγειν, to tell) was used to describe early mechanical clocks, but the use of this word (still used in several Romance languages)  for all timekeepers conceals the true nature of the mechanisms. For example, there is a record that in 1176 Sens Cathedral installed a ‘horologe’ but the mechanism used is unknown. According to Jocelin of Brakelond, in 1198 during a fire at the abbey of St Edmundsbury (now Bury St Edmunds), the monks 'ran to the clock' to fetch water, indicating that their water clock had a reservoir large enough to help extinguish the occasional fire. The word clock (from the Celtic words clocca and clogan, both meaning "bell"), which gradually supersedes "horologe", suggests that it was the sound of bells which also characterized the prototype mechanical clocks that appeared during the 13th century in Europe.
Alarm clocks, like almost all other consumer goods in the United States, ceased production in the spring of 1942, as the factories which made them were converted over to war work during World War II, but they were one of the first consumer items to resume manufacture for civilian use, in November 1944. By that time, a critical shortage of alarm clocks had developed due to older clocks wearing out or breaking down. Workers were late for, or missed completely, their scheduled shifts in jobs critical to the war effort. In a pooling arrangement overseen by the Office of Price Administration, several clock companies were allowed to start producing new clocks, some of which were continuations of pre-war designs, and some of which were new designs, thus becoming among the first "postwar" consumer goods to be made, before the war had even ended. The price of these "emergency" clocks was, however, still strictly regulated by the Office of Price Administration.
With the application of the synchronous electric motor to clocks in 1918, domestic electric clocks became popular. A synchronous electric motor runs in step with the frequency of the electric power source, which in most countries alternates at 60 hertz (cycles per second). The electric motor is coupled to a reduction gearing that drives the clock hands at the correct rate.
Any expansion or contraction of the rod caused by changes of temperature will affect the timekeeping of a pendulum; e.g., a pendulum clock with a steel rod will lose one second a day for a rise in temperature of approximately 4 °F (2.2 °C). For accurate timekeeping, the length of the pendulum must be kept as nearly constant as possible. This may be done in several ways, some of which use the differing coefficients of expansion (the amount of expansion per degree change in temperature) of different metals to obtain a cancelling-out effect. In one popular compensation method, the bob consists of a glass or metal jar containing a suitable amount of mercury. The gridiron pendulum employs rods of different metal, usually brass and steel, while in the zinc-iron tube the pendulum rod is made of concentric tubes of zinc and iron. An improved method, however, is to make the pendulum rod from a special alloy called Invar. This material has such a small coefficient of expansion that small changes of temperature have a negligible effect and can easily be compensated for if required.
This color-changing option features a radio, built-in wake-up tones, Bluetooth music streaming (so you can wake up to your favorite playlist), and USB-charging capacity to keep your phone juiced. You can preset two alarms, cycle through colors, and snooze, and even use the alarm clock's speakerphone and microphone functions to answer phone calls from paired devices. Basically, this clock does everything except your laundry.
Bring an earthy touch to your walls with this understated clock, a rustic accent for your space. Featuring a paneled distressed wood design with metal Roman numerals in a distressed gray finish, this clock brings a neutral touch to your look. Measuring at 27.5" x 27.5, this clock fits over any console or mantel space. Upkeep is easy—just wipe clean with a damp cloth—and install a AA battery (not included) to operate.
With it's quality construction and stylish mid-century modern design, the 31.5" Rumi Mid Century Wall Clock is an attractive accent for the home. Crafted entirely of iron, this large wall clock features a dark brown distressed finish and large distressed gold hands. Minimalism is reflected in the clock's open pass-through design. This clock is a must-have for anyone in search of mid-century modern inspired decor.
The clock features a solid wood core and wooden mini balls finished in rich brown tones. There are numerous silver rods radiating out from the core with some bearing wooden balls and others not. The inner assembly of balls is randomly spaced while there are twelve balls reserved for the extreme ends of hour markers. The clock is driven by a high quality Quartz movement (requiring only one AA battery; not included) 19.5 in.
It’s vital to your personal health. When you rest at night, after about twenty to thirty minutes, your body begins to enter REM sleep (if you’re lucky). Either way, your body slows down. Your heart rate hits around 40-50 BPM when you’re sleeping, compared to the 60-100 BPM you go through while you’re awake. This gives your body time to give your heart a rest, repair blood vessels, and repair muscle tissue if you worked out, or physically strained yourself during the day.
Shop alarm clocks, watches, and timers designed to wake up all types of sleepers. Standard alarm clocks are not very effective at waking deep sleepers or people with a hearing loss, especially those who are severely hard of hearing or deaf. The alarm clocks include a combination of features, such as extra loud alarms, vibrating bed shakers, lamp flashers and bright strobe light that's sure to wake you up! Discover new arrivals or shop clock favorites from Sonic Alert, Global Assistive Devices, Bellman, iLuv and more!
Mixing modern minimalism with industrial influence, this round 28" wall clock is as much a decorative accent as it is a practical timepiece. Crafted from metal, it showcases sizable Roman numerals and small spade-style hands to help you keep an eye on the hour. Its black and gold finish gives it an antiqued appearance, while its open design ensures it won’t overwhelm your arrangement. This piece requires two AA batteries (not included) to operate.
“This was a gift for my elderly, cognitively impaired mother. She was very often confused as to which day it was, the time of day, etc. She would show up at appointments on the wrong day, or think it was morning when it was evening. This clock is fantastic! It has made such a difference. Now she always knows what day and time it is. The clock is also very nice-looking. This was an excellent purchase and highly recommended. I can’t say enough good things about it.”