[Lowfer] TAG and Bill

[Stewart Nelson]

Hi Eric,

It is relatively easy to build a timer that uses a crystal
oscillator and a one-chip micro such as a PIC.  This would
save you the trouble of wiring up many divider chips, and
would be much more flexible, if you wanted to change the
behavior of your beacon in the future.

One such design is at http://www.picfun.com/equipj39.html .
This page is in Japanese, but if you have Win 2000 or XP it
should display fine.  On older OS you may need to install
fonts or a language pack.  Even if you don't understand the
text, you can get most of what you need to know from the
pictures, schematic, and source code (with English comments!).
The board pattern, schematic, and code is all available for
free download.

This unit uses two optically coupled triacs to permit
small AC loads to be switched.  You could eliminate them,
if a logic level output is all you need.  In theory, one
could also omit the LCD display, but you need some feedback
to know that the settings have be properly made.  You
could modify the code to send the "display" to a PC via
a serial port, or hard code your desired behavior, and
just plug the device in at the top of the hour.

I have some of the TCXO modules used by this project, and
would be glad to send you one.

There are many other PIC projects on the Net, and you could
probably find a timer, in English, well suited to your
application.

73,

Stewart KK7KA

----- Original Message ----- 
From: "Eric Smith" <eric@willow.nutstreet.net>
To: <lowfer@mailman.qth.net>
Sent: Sunday, February 09, 2003 11:02 AM
Subject: [Lowfer] TAG and Bill


> Rumor has it you guys might be able to point me to a circuit that would 
> toggle an output on the hour and half-hour.  I'd like to use the toggle to 
> switch one of my beacons (not LF) between two modes.
> 
> I thought of using a 555, but while I could get 30 minutes of timing out 
> of one, it wouldn't be sync'ed to the hour and half hour, which I would 
> prefer.
> 
> Any suggestions?  I know someone is already switching modes on the hour 
> and half hour.  How is it done?
> 
> Thanks in advance!
> 
> Regards,
> Eric