Any way to make LEDs mimic analog seconds movement on a cloc

[Largo]

On Sat, 21 May 2005 19:14:20 GMT, Rich Grise <richgrise@example.net>
wrote:

On Sat, 21 May 2005 09:05:19 -0700, Largo wrote:

On Sat, 21 May 2005 15:31:35 GMT, Fred Bloggs <nospam@nospam.com
wrote:



Largo wrote:
I wish to take digital clock seconds "00 to 59" and translate the
segments into 0 to 60 incrementing LED'S. IOW the digital display
converted to "analog" ring of LED's around the clock face. Thus my
digital clock display's "hh:mm" and a ring of LED's (60 for each
second). They must start at the 12 O-Clock position when seconds
makes 00.

Looking at the MAX 7219 to drive the individule LEDs. How can I
decode this?


I would forget the 7219 and use two M74HC42 available from Mouser. The
74HC42 are BCD to decimal decoders which means you input a 4-bit BCD
code in the range 0-9 and it activates 1 of 10 outputs low. So you
arrange the 60 LEDs into 6 groups of 10, use the MSD of the clock
seconds for input to one 74HC42 to select one group of 10 LEDs, and then
the clock LSD inputs to the second HC42 to select the 1 of 10 LEDs in
the group. This requires 2x 16-pin 74HC42, one current limiting
resistor, and six cheap transistor+ base resistor like so- how you
extract the seconds MSD and LSD depends on what's in the clock:

View in a fixed-width font such as Courier.

This sounds very helpful. I wish i could just recode the PIC based
digital clock since all the PIC code is offered from this site:
http://hobby_elec.piclist.com/e_pic6_76.htm

Why can't you?

The circuit already uses a BCD decoder for driving six 7-segment LED
displays. There a link to the circuit I refer which I purchased most
of the parts. It uses a PIC and also a CPLD for 3 to 8 decoder, some
divider for time accuracy and debounce logic. I use a 10Mhz metal-can
oscillator for the time keeping input. I cannot find the oscillator
used in the original description. Perhaps the circuit shown to the
group can loosen a few extra suggestions. Thanks for your
suggestions.

This circuit can be found on this link:
http://hobby_elec.piclist.com/e_pic6_71.htm

How many suggestions do you need?

The last two digits to go away, then add the roulette wheel, as you
say, run off the seconds digits logic. Or if possible, program this
into the PIC--unfortunately like Steve Ciarcia say's "My favorite
programming language is solder"

I'll need to absorb all these great suggestions. Thanks for your
patients.

Do you want to maintain the 7-segment, and _add_ the seconds roulette
wheel?

Then you'll either need 8x 8-bit shift registers, 4X 4-to-16 decoders,
or a matrix.

Or another PIC, which means you'll have to learn to program a PIC anyway.

Do you want a strictly hardware solution to this, without any programming
involved _at all_? Then be prepared to spend about a couple of hundred
bucks on discrete logic and perfboards.
No way.

Largo

Good Luck!
Rich

 

[Rich Grise]

On Sat, 21 May 2005 13:48:52 -0700, Largo wrote:

On Sat, 21 May 2005 19:14:20 GMT, Rich Grise <richgrise@example.net
wrote:

On Sat, 21 May 2005 09:05:19 -0700, Largo wrote:

On Sat, 21 May 2005 15:31:35 GMT, Fred Bloggs <nospam@nospam.com
wrote:



Largo wrote:
I wish to take digital clock seconds "00 to 59" and translate the
segments into 0 to 60 incrementing LED'S. IOW the digital display
converted to "analog" ring of LED's around the clock face. Thus my
digital clock display's "hh:mm" and a ring of LED's (60 for each
second). They must start at the 12 O-Clock position when seconds
makes 00.

Looking at the MAX 7219 to drive the individule LEDs. How can I
decode this?


I would forget the 7219 and use two M74HC42 available from Mouser. The
74HC42 are BCD to decimal decoders which means you input a 4-bit BCD
code in the range 0-9 and it activates 1 of 10 outputs low. So you
arrange the 60 LEDs into 6 groups of 10, use the MSD of the clock
seconds for input to one 74HC42 to select one group of 10 LEDs, and then
the clock LSD inputs to the second HC42 to select the 1 of 10 LEDs in
the group. This requires 2x 16-pin 74HC42, one current limiting
resistor, and six cheap transistor+ base resistor like so- how you
extract the seconds MSD and LSD depends on what's in the clock:

View in a fixed-width font such as Courier.

This sounds very helpful. I wish i could just recode the PIC based
digital clock since all the PIC code is offered from this site:
http://hobby_elec.piclist.com/e_pic6_76.htm

Why can't you?

The circuit already uses a BCD decoder for driving six 7-segment LED
displays. There a link to the circuit I refer which I purchased most
of the parts. It uses a PIC and also a CPLD for 3 to 8 decoder, some
divider for time accuracy and debounce logic. I use a 10Mhz metal-can
oscillator for the time keeping input. I cannot find the oscillator
used in the original description. Perhaps the circuit shown to the
group can loosen a few extra suggestions. Thanks for your
suggestions.

This circuit can be found on this link:
http://hobby_elec.piclist.com/e_pic6_71.htm

How many suggestions do you need?

The last two digits to go away, then add the roulette wheel, as you
say, run off the seconds digits logic. Or if possible, program this
into the PIC--unfortunately like Steve Ciarcia say's "My favorite
programming language is solder"

I've done some more looking at this, and seriously, modifying the PIC
program and modifying your segment driver matrix is about the only
practical way I can think of to do this, short of the 60-bit
shift register. The problem is that the seconds digits are multiplexed
in with all of the other digits.

You could use a couple of latches to capture the individual segments,
and then run them into a 14 x 60 diode matrix - actually, you don't
need all 14 inputs - of the 7-segment patterns, there's some redundancy
that can be treated as "don't care" - and kinda build a ROM out of
diodes, and run your 60 dots from it.

I'll need to absorb all these great suggestions. Thanks for your
patients.

Like I said, if it were me, I'd find a way to hack the PIC program.

Take a look at that roulette wheel link that someone else posted -
it couldnt hurt!

Good Luck!
Rich

 

[Rich Grise]

On Sat, 21 May 2005 13:48:52 -0700, Largo wrote:

Do you want a strictly hardware solution to this, without any
programming involved _at all_? Then be prepared to spend about a couple
of hundred bucks on discrete logic and perfboards.

No way.
Largo

Way.

1 ea. 32768 Hz watch crystal, 1 ea. 4020/4040/4060, 8 ea 74HC164,
8 ea. R-paks, 60 ea. LED. Maybe one or two logic gates - you could,
theoretically, sync it up to second 00, but that's a little more
decoding logic. Or a program hack and PIC output pin.

Do the seconds ring entirely independently of the PIC clock. Since you've
said you're going to omit the seconds digits, who's going to notice
whether they're exactly sync'd? Somebody looks at the clock, it's
7:24 and the seconds dot is at 18. They look at the clock again, it
says 7:25 and the seconds dot is at 46. Who cares? If they confront
you about it, blame me. "Some weird guy on the internet gave me the
design, and said I should call it a _feature_!"

Trust me, this is the simplest no-programming hardware solution that
anyone is going to come up with at what we're getting paid around
here. ;-)

Good Luck!
Rich

 

[Largo]

On Sat, 21 May 2005 22:37:12 GMT, Rich Grise <richgrise@example.net>
wrote:

On Sat, 21 May 2005 13:48:52 -0700, Largo wrote:

Do you want a strictly hardware solution to this, without any
programming involved _at all_? Then be prepared to spend about a couple
of hundred bucks on discrete logic and perfboards.

No way.
Largo

Way.

1 ea. 32768 Hz watch crystal, 1 ea. 4020/4040/4060, 8 ea 74HC164,
8 ea. R-paks, 60 ea. LED. Maybe one or two logic gates - you could,
theoretically, sync it up to second 00, but that's a little more
decoding logic. Or a program hack and PIC output pin.

Do the seconds ring entirely independently of the PIC clock. Since you've
said you're going to omit the seconds digits, who's going to notice
whether they're exactly sync'd? Somebody looks at the clock, it's
7:24 and the seconds dot is at 18. They look at the clock again, it
says 7:25 and the seconds dot is at 46. Who cares? If they confront
you about it, blame me. "Some weird guy on the internet gave me the
design, and said I should call it a _feature_!"

This is what originally thought--do it independently and here's how.
Another circuit using an Atmel 8051 varient chip which I think code is
easier to hack. Now there's two microcontrollers in my digital clock
but maybe the image found on:
http://www.woe.onlinehome.de/e_projects.htm and circuit at:
http://www.woe.onlinehome.de/proj_gif/leduhr.gif could do the trick.
I'd still like the LEDs to start at the 12 O-clock point when the
seconds digits are "00".

Thanks for the great pointers.

Largo

Trust me, this is the simplest no-programming hardware solution that
anyone is going to come up with at what we're getting paid around
here. ;-)

Good Luck!
Rich