HourlyChime в Android Market

HourlyChime (v. 1.1.1) Разработано Stephens Labs, LLC

Simple, unobtrusive chimes to help you keep track of the time.

Just beeps, not a musical fanfare, so that you're not embarrassed in public! (For fancy chimes, I'd recommend Bellman)

Tones at the top of the hour help you brush up on your binary too :). Some notes on how to decode the binary tones are below.

IMPORTANT NOTE: Need to open app and press "Start Chimes" on first install.

About the "prevent phone from sleeping" permission: This is just to keep the phone awake for a couple of seconds every 15 minutes, long enough to play tones. It shouldnt impact your battery life, and shouldnt make your screen turn on.

~~~ Binary tone notes ~~~
Here's how you can decode the time from the tones.
First, there is a low tone to let you know the sequence is coming.
Then there will be 4 tones that represent the hour number in binary (or 5 if you have a 24hr clock enabled)
A high pitch tone is a "1" and a medium pitch tone is a "0", and it counts from high bits to low bits.
If you're not a programmer, that will sound overly complex, but it's not so bad when you get used to it.
Here are some examples:

1 oclock in 12hr clock mode:
<low tone> medium medium medium high = 0 0 0 1 = 1

1am (01:00) in 24hr clock mode:
<low tone> medium medium medium medium high = 0 0 0 0 1 = 1

2 oclock in 12 hr clock mode:   medium medium high medium = 0 0 1 0 = 2

11 oclock in 12 hr clock mode:   high medium high high = 1 0 1 1 = 11  (=8*1 + 4*0 + 2*1 + 1*1)

20:00 in 24 hr clock mode:   high medium high medium medium = 1 0 1 0 0 = 20  (=16*1 + 8*0 + 4*1 + 2*0 + 1*0)

and so on.