Making a Multi-Month Countdown Timer

Hey, guys

I'm new at this, so I'm probably gonna need a help of help and guidance through this whole project :blush:

My idea is this: making an LED clock that would countdown the months, days, and hours (minutes maybe? if its possible) to me and my girlfriend's anniversary. Since this is a specific day timer, I would like it to keep the timer going if the batteries were to die (I'm hoping I can use some sort a battery for this that will last a least a year). I would also like it to be relatively small in size so it doesn't take up too much desk space, and would also like it to be very visually appealing, but I'm guessing that's not really your job over here : )P.

Anyway, do you think making a countdown timer like this is possible/relatively easy? Also, I'd like to make it on the cheaper side of things since I'm not super rich :stuck_out_tongue:

Hi,
LED numerals take some power... Maybe think about LCD instead..

You'll need a small Real Time Clock chip/board that can keep time for years with it's own little watch battery as well as the Arduino. See some info on the ArduinoInfo.Info WIKI HERE:

You could make a clock that uses a small "wall wart" 5V 1A supply to run the Arduino and LED displays If it is powered off and back on the RealTime Clock would not lose the time/date..

Real time clock is not necessary, although it increases the precision of the clock significantly.
Start by checking this:
http://playground.arduino.cc/Code/time

There is a library for clock called "Alarms" I guess you could use that to run a clock, do the countdown, and even sing "Happy Birthday" as required, year in, year out until you got old and/or tired of it. It could even be resettable in the event of a new girlfriend.

Indeed, to make the job more interesting, you might include some bio-monitoring device so that it can operate with multiple girlfriends.

The timer part of the circuit I posted here - Please comment on my data logger design - Project Guidance - Arduino Forum
may be a place to start, (you don't need the SD card) the timer has a backup battery which will keep the clock time if the power fails.

If an LCD uses less power, that’s what I’ll use :slight_smile:
And about the real time clock: if its more precise, I’d love to use it! But would it add a lot of difficulty to making it?

For the Real Time Clock, see the link I posted or google "Arduino DS1307" there is loads of info

I believe that if you want accurate time/date over several months you need a little RTC module with backup battery. They are less than $10

sirch:
For the Real Time Clock, see the link I posted or google "Arduino DS1307" there is loads of info

Should I be using the DS1305, like the one used in the link you posted, or DS1307?

The main difference is that the DS1305 has 2 alarms (i.e. it can send interrupts to your Arduino at scheduled times of day) where as the DS1307 doesn't. I don't think your application needs the alarms.

sirch:
The main difference is that the DS1305 has 2 alarms (i.e. it can send interrupts to your Arduino at scheduled times of day) where as the DS1307 doesn't. I don't think your application needs the alarms.

Alright, sounds good. So now I have the DS3107, what about the LCD? Is there any one I should get in particular?

The standard Ardunio library works with any LCD that has a Hitachi HD44780 compatible interface, so your life will be simpler if you go for one of those. They are all over ebay, check the specs for compatibility, power consumption, colour etc.

Depends on how many Arduino pins you want to use for the LCD and what else you are doing with pins.

The easy-to-use solution using just 2 pins (plus Vcc and Gnd) is This Type:

These have a LED backlight that you can turn on and off to save power if you wish (Or maybe turn off if you sense the main power has gone off?) 4 lines would allow quite a bit of information displayed. Of course you can have that info change with software, maybe time/date, temperature etc. Cute messages that randomly appear?? "I am so NOT Bored Yet!" Hmm..

terryking228:
Depends on how many Arduino pins you want to use for the LCD and what else you are doing with pins.

The easy-to-use solution using just 2 pins (plus Vcc and Gnd) is This Type:

These have a LED backlight that you can turn on and off to save power if you wish (Or maybe turn off if you sense the main power has gone off?) 4 lines would allow quite a bit of information displayed. Of course you can have that info change with software, maybe time/date, temperature etc. Cute messages that randomly appear?? "I am so NOT Bored Yet!" Hmm..

I do like the idea of the random messages showing up once in a while. How would I go about doing this? I don't think it'll be necessary to have a backlight, and I don't want to go through more batteries than I have to

Okay, so I have the DS3107 and the 2-pin LCD. Is there anything else I should order?

Where'd everyone go? :cold_sweat: :roll_eyes: :disappointed_relieved:

In the USA, Thanksgiving. Back now.

Seriously, just get started on this and get it running laid out on the table. Package later. Probably get some nice pushbuttons is you want any other functions like display the current time/date as an option to the countdown.

I like THESE big ones.

DISCLAIMER: Mentioned stuff from my own shop...

Ah, right

Anyway, while everyone was away, I was thinking about making this into a full-blown calendar, with a timer built in, perhaps showing at the bottom of the display. Is that possible?

Like terryking said, just get on and build somehting, I suggest starting with something simple. It's your project, we can help but you need to design and built it.

Alright, then I'll start :slight_smile:
Now, bear in mind, I'm completely new to this, so I'm gonna need a little more help to start. I know what timer piece and screen to buy, but what other basics do I need? I figure some type of Arduino board and a way to power it?