[clug] Countdown Timer

[Adam Thomas]

Hi Lana,

On 26 October 2010 17:15, Lana Brindley <lanabrindley at gmail.com> wrote:
> I want to try and rig up some kind of a countdown timer to use on the front
> of a stage to time talks, TED style.

I'm glad you asked. :)

I've been thinking the same thing recently.

>
> I've thought of using a laptop and some kind of full-screen countdown
> program (that's as far as the detailed planning went, I confess), but
> thought the hardware hackers out there would probably have some more elegant
> solutions at their disposal.

Here's another Javascript counter which allows you to specify the
number of minutes in the URL: http://github.com/apgwoz/timer/

>
> So, hit me with your ideas ... ?

I've been playing with my mhvboard (an Arduino like AVR prototyping
board) and my Sure Electronics 8x32 LED Matrix displays[0]. I bought
four of the displays for about $12 each. Laid out in a 16x64 display
they work really well for displaying four 16 by 16 pixel glyphs. I
haven't really tested how far away they can be seen comfortably but it
really should be good enough for sitting at the edge of a stage.

[0] http://www.sureelectronics.net/goods.php?id=907

Sure Electronics also have some whopping great 7 inch high 7 segment
displays[1] for about $25 each. These can probably be clearly seen
from tens of meters away. They also have a 2 digit 4 inch 7 segment
display[2] that's less than half the price per digit which is also
worth looking at.

[1] http://www.sureelectronics.net/goods.php?id=721
[2] http://www.sureelectronics.net/goods.php?id=136

There are plenty of other options for the displays, those are just the
ones I've been looking at most recently.

You'd need a micro controller, a power supply and some kind of
interface. Probably a wireless connection to a computer for setting,
starting, stopping and viewing where it's up to. Buttons on the front
and status LEDs on the back of the box might be a little bit cheaper
then wireless and less likely to cause setup delays but aren't nearly
as cool.

You can probably put all the electronics together from between $80 and
$150 if you're starting from scratch. Project cases are an unknown for
me at the moment but you might be able to salvage something
interesting.

Come along to a MakeHackVoid[3] makers meeting (which will be a
fortnight from now) and I'll see if I can put something less vague
together with the parts I have at the moment.

[3] http://makehackvoid.com

Adam.

>
> L
>
> --
> Cheers! Lana
>
> I never teach my pupils. I only attempt to provide the conditions in which
> they can learn.
>  - Albert Einstein
>
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