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counter circuit help needed

S

Silvester

Jan 1, 1970
0
I'm looking for some help with a counting circuit.

I have a schematic from an OLD Radio Shack book that drives a 7490 with
a 555.
The 7490 dumps into a 7448, which in turn displays the number on a
7-segment LED.

I need a similar circuit that will count DOWN from a predefined number
- say 255 using DIP switches to set the number in binary.

The problem is, I have been unable to find anything on the internet.

I plan to use a matched pair of LEDs (IR emitter/receiver) to count
objects passing a point rather than the 555 timer portion of the
circuit.
And I need a RESET button to send the count back to 255 or what ever
number is preconfigured by the DIP switches.

Can anyone help me out?


Silvester
 
R

Rich Grise

Jan 1, 1970
0
I'm looking for some help with a counting circuit.

I have a schematic from an OLD Radio Shack book that drives a 7490 with
a 555.
The 7490 dumps into a 7448, which in turn displays the number on a
7-segment LED.

I need a similar circuit that will count DOWN from a predefined number
- say 255 using DIP switches to set the number in binary.

The problem is, I have been unable to find anything on the internet.

I plan to use a matched pair of LEDs (IR emitter/receiver) to count
objects passing a point rather than the 555 timer portion of the
circuit.
And I need a RESET button to send the count back to 255 or what ever
number is preconfigured by the DIP switches.

Can anyone help me out?
Go to the "housewares" or "kitchen aids" department of your local
supermarket or general store, and get a digital kitchen timer for
about $10.00.

Cheers!
Rich
 
P

petrus bitbyter

Jan 1, 1970
0
Silvester said:
I'm looking for some help with a counting circuit.

I have a schematic from an OLD Radio Shack book that drives a 7490 with
a 555.
The 7490 dumps into a 7448, which in turn displays the number on a
7-segment LED.

I need a similar circuit that will count DOWN from a predefined number
- say 255 using DIP switches to set the number in binary.

The problem is, I have been unable to find anything on the internet.

I plan to use a matched pair of LEDs (IR emitter/receiver) to count
objects passing a point rather than the 555 timer portion of the
circuit.
And I need a RESET button to send the count back to 255 or what ever
number is preconfigured by the DIP switches.

Can anyone help me out?


Silvester

You can use the 74LS191 for binary up/down counting. Two pieces cascaded
will count up/down the 0-255 range and you can use dipswitches for the
preset. It will not be very easy to make a decimal readout but you can use
binary - using LEDs - instead. Guess you'd best start downloading the
appropriate datasheet.

petrus bitbyter
 
S

Silvester

Jan 1, 1970
0
Electronics is really not my thing. I can assemble a schematic, but not
design a circuit.

Is there any chance you could set me up with a schematic of what you
are thinking?
 
R

Rich Grise

Jan 1, 1970
0
"Silvester" <[email protected]> schreef in bericht

You can use the 74LS191 for binary up/down counting. Two pieces cascaded
will count up/down the 0-255 range and you can use dipswitches for the
preset. It will not be very easy to make a decimal readout but you can use
binary - using LEDs - instead. Guess you'd best start downloading the
appropriate datasheet.

Three of '190 or '192 would count in BCD, so you could go to 999, if you
wanted to.

Cheers!
Rich
 
J

John Fields

Jan 1, 1970
0
Electronics is really not my thing. I can assemble a schematic, but not
design a circuit.

Is there any chance you could set me up with a schematic of what you
are thinking?

---
From:

http://groups.google.com/support/bin/answer.py?answer=12348&topic=250

"Summarize what you're following up.

When you click "Reply" under "show options" to follow up an existing
article, Google Groups includes the full article in quotes, with the
cursor at the top of the article. Tempting though it is to just
start typing your message, please STOP and do two things first. Look
at the quoted text and remove parts that are irrelevant. Then, go to
the BOTTOM of the article and start typing there. Doing this makes
it much easier for your readers to get through your post. They'll
have a reminder of the relevant text before your comment, but won't
have to re-read the entire article. And if your reply appears on a
site before the original article does, they'll get the gist of what
you're talking about."

In other words, be considerate and leave a little of the article
you're responding to in your reply, and bottom post. That makes it
easy for us all to see to whom and to what you're responding without
having to backtrack through the header trail to see where you're
coming from.
 
J

John Fields

Jan 1, 1970
0
---
From:

http://groups.google.com/support/bin/answer.py?answer=12348&topic=250

"Summarize what you're following up.

When you click "Reply" under "show options" to follow up an existing
article, Google Groups includes the full article in quotes, with the
cursor at the top of the article. Tempting though it is to just
start typing your message, please STOP and do two things first. Look
at the quoted text and remove parts that are irrelevant. Then, go to
the BOTTOM of the article and start typing there. Doing this makes
it much easier for your readers to get through your post. They'll
have a reminder of the relevant text before your comment, but won't
have to re-read the entire article. And if your reply appears on a
site before the original article does, they'll get the gist of what
you're talking about."

In other words, be considerate and leave a little of the article
you're responding to in your reply, and bottom post. That makes it
easy for us all to see to whom and to what you're responding without
having to backtrack through the header trail to see where you're
coming from.
 
E

ehsjr

Jan 1, 1970
0
Silvester said:
I'm looking for some help with a counting circuit.

I have a schematic from an OLD Radio Shack book that drives a 7490 with
a 555.
The 7490 dumps into a 7448, which in turn displays the number on a
7-segment LED.

I need a similar circuit that will count DOWN from a predefined number
- say 255 using DIP switches to set the number in binary.

The problem is, I have been unable to find anything on the internet.

I plan to use a matched pair of LEDs (IR emitter/receiver) to count
objects passing a point rather than the 555 timer portion of the
circuit.
And I need a RESET button to send the count back to 255 or what ever
number is preconfigured by the DIP switches.

Can anyone help me out?


Silvester

Take a look at the following kit to see if it will work
for you:

http://www.electrokits.com/electronics/relays-remotes-switches-timers/34.htm
 
R

Roy L. Fuchs

Jan 1, 1970
0
I've posted a schematic on alt.binaries.schematics.electronic.

Could you post it again, or the link to the non binary access
workaround?
 
R

Roy L. Fuchs

Jan 1, 1970
0
Cool.

Funny, I worked for the premiere pharmaceutical tablet counter maker
at one time (hole in the wall 12 employees).

It had 16 optical channels, and only got one parallax error per one
thousand pill drops, if it ever got any.

It was possible though as two pills could pass a sensor together and
be read as one, though rare. They were LEDs and detectors in 16
circumferentially placed pill channels sitting under a cone.

Pour pills in at top, and stop when your prescription number is
reached. All channel count up and add to show in the display.
Pull drawer out pour into bottle.

Pharmacists that had the bucks didn't have to scrape fives with the
pill ladle!

Anyway... thanks.
 
M

Michael A. Terrell

Jan 1, 1970
0
Roy L. Fuchs said:
Cool.

Funny, I worked for the premiere pharmaceutical tablet counter maker
at one time (hole in the wall 12 employees).

It had 16 optical channels, and only got one parallax error per one
thousand pill drops, if it ever got any.

It was possible though as two pills could pass a sensor together and
be read as one, though rare. They were LEDs and detectors in 16
circumferentially placed pill channels sitting under a cone.

Pour pills in at top, and stop when your prescription number is
reached. All channel count up and add to show in the display.
Pull drawer out pour into bottle.

Pharmacists that had the bucks didn't have to scrape fives with the
pill ladle!

Anyway... thanks.


Now, a lot of the drug companies pre-package in common quantities.
The medicine that I get from the VA is all pre-packaged for either 30 or
90 days.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
E

Eric R Snow

Jan 1, 1970
0
Now, a lot of the drug companies pre-package in common quantities.
The medicine that I get from the VA is all pre-packaged for either 30 or
90 days.
They just weigh my pills to count 'em at my local pharmacy.
ERS
 
M

Michael A. Terrell

Jan 1, 1970
0
Eric said:
They just weigh my pills to count 'em at my local pharmacy.


I don't have to go to a pharmacy. I log in to
http://www.myhealth.va.gov/ and click on the refills that I need. They
show up in my mailbox a few days later. Very handy, since the nearest VA
pharmacy is over 100 miles away.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
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