Six, 7-segment LEDs With Decimals

Need we say more!

Digital clock colons

Useful for displaying the date or the time Year-Month-Day (yy-mm-dd) or Hour-Minutes-Seconds (hh-mm-ss)

One 4 kHz beeper

With the beeper you can add a chirp to every second that passes increasing the sense of urgency of your countdown. Or you can use it as an alarm at the end of your countdown.

12 Indicator LEDs

There are 12 LEDs across the top that can be used for indicating a variety of things. For instance As a visual indicator like a speedometer or level indicator. Or you can label the LEDs and have them eliminate represent different modes or functions.

Photo Resistor

The kit comes with a photo resistor. You can use it as an experimental input and display the analog output of the LED display. Or If you are trying to design the perfect alarm clock, you can use the photo resistor to detect the amount of ambient light and have your alarm clock display at full brightness during the daytime and appropriately dim the display at night.

I2C Socket

The Arduino is able to count clock cycles and keep track of time. However if it is unplugged it will lose time. This is not a problem for less critical count downs at shorter times.

However if you want to keep track of time over a longer period you may consider using a real time clock chipset with battery backup. There are lots of them available, many of them are I2C compatible and are easily connected through this port. Another Potential option for a timekeeping device is a global positioning system (GPS). GPS Received very accurate time information from satellites. This way there will be no need to set your clock as long as you have access to satellite signals.

The I2C socket can also be used for communicating with other Arduinos.

Rotary Encoder

The rotary encoder Is a optional add-on. It can be potentially used for setting the time or for the length of your countdown. I personally like rotary encoders better than potentiometers. Rotary encoders can be turned a limitless number of times. Whereas potentiometers it’s often less than a full revolution. This particular Rotary encoder also has a built-in button. So you can turn it or push it.

Main wiki page for this project

Assembly Instructions