[GRLUG] Time Clocks and Software

[Ben Rousch]

On Wed, Jan 26, 2011 at 12:06 AM, Bill Littlejohn <billl at mtd-inc.com> wrote:
>
>> We have a series of intercoms in the shop that emit a buzz to let
>> people know when it's time to start work, go to lunch, or go home. Our
>> current time clock software sets a schedule for those buzzers and
>> stores it on the time clock. The time clock then trips a relay (or
>> something like that) at the appropriate time. The inexpensive clocks
>> do not seem to have to capability to control such a buzzer system.
>>
>
> Not sure how averse you are to a bit of programming.. but you did mention
> putting something together. Arduino's have a ton of code available already.
> You would just have to adapt what's already there.
>
> An arduino with a 'buzzer file' on an SD card, solid state relay, and DS1307
> RTC would allow you to replace the timeclock relay without needing a
> computer to plug a usb relay into.
>
> Arduino
> http://www.adafruit.com/index.php?main_page=product_info&cPath=17&products_id=325
> Ethernet shield with micro SD
> http://www.adafruit.com/index.php?main_page=product_info&cPath=17_21&products_id=201
> DS1307 on breakout board
> http://www.adafruit.com/index.php?main_page=product_info&cPath=42&products_id=264
>
> That's about $84.00, plus you'll need a relay similar to the one in your
> current timeclock.

This is more along the lines of what I thought people would suggest.
Very interesting. My major concern with this is clock drift. Ideally
the clock needs to be correct to within a few seconds, or I need to be
able to regularly correct time via something like NTP. Also I have no
experience with Arduino, so there would be a learning curve.

I've just started looking into plug computers, like the SheevePlug. A
Linux install on a wall wart, with a USB port. Maybe I can plug in one
of the previously-suggested USB relays and create a fairly simple
system. http://en.wikipedia.org/wiki/SheevaPlug


-- 
  Ben Rousch
  brousch at gmail.com
  http://ishmilok.blogspot.com/

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