20 LED Chaser

[IanW]

"IanW" <spammenot@blah.com> wrote in message news:gef70q$ool$1@aioe.org...

"Jasen Betts" <jasen@xnet.co.nz> wrote in message
news:ge6kpt$895$1@reversiblemaps.ath.cx...
On 2008-10-27, IanW <spammenot@blah.com> wrote:
Hello

Does anyone have a circuit diagram for a 20 LED chaser please? All the
ones
I can find via Google seem to be about 10.

use a 4047 wired as an astable multivibrator for the oscilator.
and a 4017 decade counter, clock the 4017 from pin 10 of the 4047
use pins 10 and 11 to select between two banks of 10 LEDs.

if you use high efficiency LEDs the whole thing will run off 3v with
just those two chips a resistor and a capacitor for the clock and two
resistors to control brightness.

Hi Jasen. Thanks for the schematic on abse, that looks good too and makes
3 circuits to try out

With regard to D21 & D22 on your schematic - given I intend using a 9V
battery, would I be right in assuming that a 9V 0.5W Zener would be the
correct type for those two diodes?

Incidenatlly, on all these circuits would you generally use ceramic, poly
layer or other types of capacitor or does it not matter in this kind of
circuit?

Regards
Ian

 

[ehsjr]

IanW wrote:

"ehsjr" <ehsjr@NOSPAMverizon.net> wrote in message
news:gVoOk.1402$Jv2.175@nwrddc01.gnilink.net...


The diagram at
http://focus.ti.com/lit/ds/symlink/cd4017b.pdf
shows 3 4017's, not two. It uses the first 4017
to control LEDs 1 through 9, the second to control
LEDs 10 through 17, and the third to control
LEDS 18, 19 and 20.

I can email a jpg of the schematic for that circuit.

I will "draw" an ascii schematic below that shows
the interconnections required between the 4017 ICs.
It does not show the LED wiring - that wiring will
be described. LED wiring is very close to what is
shown at the url you posted for free circuits. You
can use the 4011 clock circuit from that page.

CLOCK +-----------------------------------------------+
| | +-----------+ +-----------+ |
| | | | | | |
| ---15---- | ---15---- | ---15---- |
| | | | | | | | | |
+----14 | | +---14 | | +---14 | |
| | IC1 | | | | IC2 | | | | IC3 | |
| +-13 | | | +-13 | | | +-13 | |
| | | | | | | | | | | | | | |
| | --3--11-- | | | --3--11-- | | | ---10---- |
| | | | | | | | | | | | | |
| | +-- | ----+ | | +-- | ----+ | | +-------+
| | | | | | | | |
| +--------+ | +--------+ | +--+--[15K]----+
| | /e | /e | |
| +-[1K]-| 2N3904 +-[1K]-| Gnd [C1]
| \c Q1 Q2 \c |
| | | +9V
+--------------------+-------------------+

How it works: At power on, C1 (.01uf) and the 15K resistor send
a (+) reset pulse to IC1, which forces pin 3 on (+). That in
turn resets IC2, which in turn resets 1C3, so all three 4017's
are set to 0 upon power on. There is _no_ LED connected to
pin 3 for IC2 or IC3, but there is an LED (LED1) connected to
IC1 pin 3. Clock pulses are applied to IC1 pin 14 and to the
collectors of both transistors. These transistors (both are
2N3904's, but you can use almost any NPN) will not pass the
clock pulses through to the emitter, until the base goes positive.

With each clock pulse, IC1 advances one count, lighting
LEDs 2,3,4,5,6,7,8 and 9 in sequence. The next clock pulse
extinguishes LED9 and causes pin 11 to go + . That places
+ on the base of Q1 and on pin 13 of IC1. With pin 13 positive,
IC1 is frozen until it gets a reset pulse. With the base
of Q1 +, the same clock pulse that moved IC1 causes IC2 to
increment from 0 to 1 and light LED 10. (Since there is no LED
connected to the count 0 pin (pin 3), IC2 must increment to 1
before it can light an LED.) IC2 is wired to LEDS 10 through
17, as mentioned earlier. It operates identically to IC1.

When IC2 places + on its pin 11, it places + on the base of Q2
and freezes as IC1 did. Because the base is +, Q2 can now pass
clock pulses to IC3, and it can advance. It lights LEDs
17, 18, 19 and 20 in sequence. At the next clock pulse it places
a plus on pin 10, which sends a reset pulse to IC1, and the entire
operation starts over.

_LED wiring recap:_
All 20 of the LED cathodes connect to a resistor (R3 at the url
you posted) - make it 3.3K and use the LEDs John recommended.
LEDs 1-9 connect to IC1 as shown on the url you posted. _NO_
LED is connected to pin 11 of IC1. LEDs 10-17 connect to
IC2. _NO_ LED is connected to pin 3 or pin 11 of IC2. Otherwise,
the LED wiring is the same as that shown at t6he url. LEDs
18, 19 and 20 are connected to IC3 pins 2, 4 and 7 respectively.


Hi Ed. That's a brilliant and very clear description .

I think I understand the function of the two types of IC but I'm not sure
sure what the transistors are actually for? John's circuit doesn't feature
any - is that because U1C & U1D perform a similar function?

I have some breadboard, so am going to make both yours and John's circuits
and work out the component layout. Should be fun.

Thanks very much for your help
Ian

Hi Ian,

The transistors act as "and gates". That is, they
need a clock pulse at the collector AND a positive
on the base to provide clock pulses to the 4017's.

The diagram at the TI (figure 19) site shows "and gates"
connected between the 4017's to gate the clock pulse to
the next 4017 at the proper time.

You can read about the "and gate" at
http://www.doctronics.co.uk/Subsystems/AND_gate.htm

I used transistors instead of an IC for the ands, figuring
it might be easier for you to get them.

By the way, building both circuits is a good idea - the
more ways you have to do something, the better off you
are.

Ed

 

[ehsjr]

IanW wrote:

"Jasen Betts" <jasen@xnet.co.nz> wrote in message
news:ge6kpt$895$1@reversiblemaps.ath.cx...

On 2008-10-27, IanW <spammenot@blah.com> wrote:

Hello

Does anyone have a circuit diagram for a 20 LED chaser please? All the
ones
I can find via Google seem to be about 10.

use a 4047 wired as an astable multivibrator for the oscilator.
and a 4017 decade counter, clock the 4017 from pin 10 of the 4047
use pins 10 and 11 to select between two banks of 10 LEDs.

if you use high efficiency LEDs the whole thing will run off 3v with
just those two chips a resistor and a capacitor for the clock and two
resistors to control brightness.


Hi Jasen. Thanks for the schematic on abse, that looks good too and makes 3
circuits to try out

I guess I might be pushing my luck here, but any suggestions for a chaser
that will work regardless of the current that the LEDs require? I've mail
ordered some high eff LEDs, since my local electronics supplier didn't have
any in stock today, but there's more choice of size/colour/brightness with
normal LEDs.

Regards
Ian

Hi Ian,

You could use a transistor array chip, like the ULN2001,
as the LED driver to drive 7 LEDs (or fewer) per chip.
Or you could use individual NPN transistors. The output
from the 4017 would connect to the input of the chip or
the base of the transistor through a resistor. You
need to calculate the cathode resistor for higher
current if you don't use the high efficiency LEDs.
The formula is: R = (Vs-Vf)/Iled where Vs is the supply
voltage, Vf is the forward voltage spec of the LED
and Iled is the current you want.

Ed

 

[Rich Grise]

On Fri, 31 Oct 2008 08:18:35 +0000, IanW wrote:

Sorry I should have been more specific, I meant I assembled the 10 LED
chaser that I posted previously about:

http://www.free-circuit-diagrams.com/light-led/page-1/169/led-chaser

and it doesn't work properly.

It shouldn't. According to the data sheet, the 4017 has about .36 mA Ioh.

You need a bank of inverters, transistors, or FETs to drive the LEDs.

Hope This Helps!
Rich

 

[Bill Bowden]

On Oct 27, 1:51 pm, "IanW" <spamme...@blah.com> wrote:

Hello

Does anyone have a circuit diagram for a 20 LED chaser please? All the ones
I can find via Google seem to be about 10.

Thanks
Ian

There is a circuit for chasing 18 LEDs at :
http://ourworld.compuserve.com/homepages/Bill_Bowden/4017-7.gif

Or, you can chase up to 100 LEDs using a couple decade counters and
additional transistors for each LED.

http://ourworld.compuserve.com/homepages/Bill_Bowden/25led.gif

-Bill

 

[Bill Bowden]

On Oct 31, 6:39 pm, Bill Bowden <wrongaddr...@att.net> wrote:

On Oct 27, 1:51 pm, "IanW" <spamme...@blah.com> wrote:

Hello

Does anyone have a circuit diagram for a 20 LED chaser please? All the ones
I can find via Google seem to be about 10.

Thanks
Ian

There is a circuit for chasing 18 LEDs at :http://ourworld.compuserve.com/homepages/Bill_Bowden/4017-7.gif

Or, you can chase up to 100 LEDs using a couple decade counters and
additional transistors for each LED.

http://ourworld.compuserve.com/homepages/Bill_Bowden/25led.gif

-Bill

Correction. That should have been 1 transistor for each row and
column. In other words, if you assemble the matrix with 4 rows and 5
columns to control 20 LEDs, you need 9 transistors to drive the rows
and columns. The reset line of each counter needs to be connected to
the appropriate output pin for the desired total. The schematic shows
25 LEDs, but can be expanded to 100. See the text for more details.

http://ourworld.compuserve.com/homepages/Bill_Bowden/page5.htm#60sec.gif

-Bill

 

[Jasen Betts]

On 2008-10-31, IanW <spammenot@blah.com> wrote:

"IanW" <spammenot@blah.com> wrote in message news:gef70q$ool$1@aioe.org...

"Jasen Betts" <jasen@xnet.co.nz> wrote in message
news:ge6kpt$895$1@reversiblemaps.ath.cx...
On 2008-10-27, IanW <spammenot@blah.com> wrote:

use a 4047 wired as an astable multivibrator for the oscilator.
and a 4017 decade counter, clock the 4017 from pin 10 of the 4047
use pins 10 and 11 to select between two banks of 10 LEDs.

if you use high efficiency LEDs the whole thing will run off 3v with
just those two chips a resistor and a capacitor for the clock and two
resistors to control brightness.

Hi Jasen. Thanks for the schematic on abse, that looks good too and makes
3 circuits to try out

With regard to D21 & D22 on your schematic - given I intend using a 9V
battery, would I be right in assuming that a 9V 0.5W Zener would be the
correct type for those two diodes?

Pretty much any sort of diode is fine there (1N914 or 1N4148 are good
choices, or any rectifier diode) the purpose of the diode is to protect
the unlit LEDs from reverse voltage which (if it's more than 5V) may
damage them.

Some LEDS (in my experiencee) are not damaged by by upto 12 volts reverse
bias, but some are damaged by less (the documentation often says 5V is the
most to allow, and I've seen one damaged by 6V)
small diodes are cheap and only 2 areneeded.

At any one time (without the diodes) 9 of the LEDS would be exposed to
reverse voltage and 10 of them to (near) zero voltage and one of them
to forwards voltage. With the diodes the 9 will get near zero too.

Incidenatlly, on all these circuits would you generally use ceramic, poly
layer or other types of capacitor or does it not matter in this kind of
circuit?

I'd use a polyester. For slow circuits like this the type of capacitor
is not critical.

Bye.
Jasen

 

[ehsjr]

Rich Grise wrote:

On Fri, 31 Oct 2008 08:18:35 +0000, IanW wrote:

Sorry I should have been more specific, I meant I assembled the 10 LED
chaser that I posted previously about:

http://www.free-circuit-diagrams.com/light-led/page-1/169/led-chaser

and it doesn't work properly.


It shouldn't. According to the data sheet, the 4017 has about .36 mA Ioh.

You need a bank of inverters, transistors, or FETs to drive the LEDs.

Hope This Helps!
Rich

That might be true at extreme heat (257 degrees F), but
at normal temperatures the 4017 can source several mA and
drive LEDs directly. If you want a 4017 to drive a LED to its
max current rating, you have to use a high efficiency LED,
or use one of the driver circuits you mentioned to drive
a "regular" LED. The 4017 as wired in the schematic at
the posted url will work fine without drivers, providing
enough current to the LEDs for them to glow brightly.

Ed

 

[Jasen Betts]

On 2008-10-31, IanW <spammenot@blah.com> wrote:

Hi Jasen. Thanks for the schematic on abse, that looks good too and makes 3
circuits to try out

I guess I might be pushing my luck here, but any suggestions for a chaser
that will work regardless of the current that the LEDs require? I've mail
ordered some high eff LEDs, since my local electronics supplier didn't have
any in stock today, but there's more choice of size/colour/brightness with
normal LEDs.

one way is to use transistors and flip all the LEDs.

the bottom end use NPN transistors with 3.3K resistors from the 4017 to the
base and the emiters connected to ground (battery negative). (you'll need 10) for
20mA LEDs (or even 60ma) something like BC547B or PN2222 would be suitable.
if you want to use high power leds the use a darlington transistor
like BD682 the top end use a 3.3K resistor from the 4047 outputs (pin
10 and 11) to the base of a PNP transistor BC337 or 2n2907, the
emitters of these two got to battery positive trans and the collectors
go to resistorc chosen for the apropritate LED current (470 ohms if
you want about 18mA through the LEDS) then these transistors go to the
LED anodes (10 leds each),

--

Bye.
Jasen

 

[Jasen Betts]

On 2008-10-31, IanW <spammenot@blah.com> wrote:

Sorry I should have been more specific, I meant I assembled the 10 LED
chaser that I posted previously about:

http://www.free-circuit-diagrams.com/light-led/page-1/169/led-chaser

and it doesn't work properly.

that bit with the 4011 looks unusual try instead the arrangement used by
John in the top left corner of his circuit. (that part will work with
the 4011 chip too)

Bye.
Jasen

 

[John Fields]

On Fri, 31 Oct 2008 08:18:35 -0000, "IanW" <spammenot@blah.com> wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
news:9dlkg49kpa9t8ouhdcl8au0pi1eebm0qr2@4ax.com...

I have actually tried assembling the circuit on that
free-circuit-diagrams.com site, however it doesn't work properly. That is,
the LEDs just seem to flash randomly, some flickering very very briefly
and
then one will stay lit for 2-3 seconds and it'll seem to lock up for a bit
before randomly flashing again. I wonder if this is because of the 20mA
LEDs?

Thanks for taking the time to help and explaining things

---
My pleasure!

I'm not familiar with that site; do you have a link to their simulator?

Sorry I should have been more specific, I meant I assembled the 10 LED
chaser that I posted previously about:

http://www.free-circuit-diagrams.com/light-led/page-1/169/led-chaser

and it doesn't work properly.

---
Here's a brute force one over on abse that's _guaranteed_ to work:

news:59hpg454qhuls80gbombs7l8jf9lchkd9l@4ax.com

JF

 

[IanW]

"John Fields" <jfields@austininstruments.com> wrote in message
news:slhpg4128to0i0s3er7c2rhtr8aeh8t61u@4ax.com...

---
Here's a brute force one over on abse that's _guaranteed_ to work:

news:59hpg454qhuls80gbombs7l8jf9lchkd9l@4ax.com

Thanks. I've got more circuits than I can shake a stick at now

I'm just printing them all off and still haven't managed to get all the
components for one complete circuit yet! Should have the bits for one of the
high eff LED circuits tomorrow.

Btw, I saw the pic of your recreation room on abse. A computer, pool table,
guitar and a cat - what more could one ask for!

Regards
Ian

 

[IanW]

"Jasen Betts" <jasen@xnet.co.nz> wrote in message
news:geh6qc$flu$1@reversiblemaps.ath.cx...

On 2008-10-31, IanW <spammenot@blah.com> wrote:

Hi Jasen. Thanks for the schematic on abse, that looks good too and makes
3
circuits to try out

I guess I might be pushing my luck here, but any suggestions for a chaser
that will work regardless of the current that the LEDs require? I've mail
ordered some high eff LEDs, since my local electronics supplier didn't
have
any in stock today, but there's more choice of size/colour/brightness
with
normal LEDs.

one way is to use transistors and flip all the LEDs.

the bottom end use NPN transistors with 3.3K resistors from the 4017 to
the
base and the emiters connected to ground (battery negative). (you'll need
10) for
20mA LEDs (or even 60ma) something like BC547B or PN2222 would be
suitable.
if you want to use high power leds the use a darlington transistor
like BD682 the top end use a 3.3K resistor from the 4047 outputs (pin
10 and 11) to the base of a PNP transistor BC337 or 2n2907, the
emitters of these two got to battery positive trans and the collectors
go to resistorc chosen for the apropritate LED current (470 ohms if
you want about 18mA through the LEDS) then these transistors go to the
LED anodes (10 leds each),

Got your circuit on abse thanks. The BC337 is an NPN transistor according to
my catalog - do you mean BC327?

Regards
Ian

 

[IanW]

"ehsjr" <ehsjr@NOSPAMverizon.net> wrote in message
news:QrIOk.1718$Jv2.516@nwrddc01.gnilink.net...

You could use a transistor array chip, like the ULN2001,
as the LED driver to drive 7 LEDs (or fewer) per chip.
Or you could use individual NPN transistors. The output
from the 4017 would connect to the input of the chip or
the base of the transistor through a resistor. You
need to calculate the cathode resistor for higher
current if you don't use the high efficiency LEDs.
The formula is: R = (Vs-Vf)/Iled where Vs is the supply
voltage, Vf is the forward voltage spec of the LED
and Iled is the current you want.

Thanks. Jasen has posted an individual transistor style circuit which looks
good and John posted a 4xIC 74 series IC circuit which looks interesting. So
that's 2 more to get on the breadboard

Regards
Ian

 

[Rich Grise]

On Sun, 02 Nov 2008 19:29:18 +0000, IanW wrote:

"John Fields" <jfields@austininstruments.com> wrote in message

Here's a brute force one over on abse that's _guaranteed_ to work:

news:59hpg454qhuls80gbombs7l8jf9lchkd9l@4ax.com

Thanks. I've got more circuits than I can shake a stick at now

I'm just printing them all off and still haven't managed to get all the
components for one complete circuit yet! Should have the bits for one of
the high eff LED circuits tomorrow.

Btw, I saw the pic of your recreation room on abse. A computer, pool
table, guitar and a cat - what more could one ask for!

A cat trap, to get rid of the evil thing.
A dog.
A hot babe who likes me. ;-)
A drink.
A doobie.
A pizza.
etc., etc., etc.... ;-)

Cheers!
Rich

 

[John Fields]

On Mon, 03 Nov 2008 20:44:49 GMT, Rich Grise <rich@example.net> wrote:

On Sun, 02 Nov 2008 19:29:18 +0000, IanW wrote:
"John Fields" <jfields@austininstruments.com> wrote in message

Here's a brute force one over on abse that's _guaranteed_ to work:

news:59hpg454qhuls80gbombs7l8jf9lchkd9l@4ax.com

Thanks. I've got more circuits than I can shake a stick at now

I'm just printing them all off and still haven't managed to get all the
components for one complete circuit yet! Should have the bits for one of
the high eff LED circuits tomorrow.

Btw, I saw the pic of your recreation room on abse. A computer, pool
table, guitar and a cat - what more could one ask for!

A cat trap, to get rid of the evil thing.

---
I like 'em.

They're feisty, they cover their shit, and when they need affection, or
food, they shamelessly rub up against you so you don't have to guess.

---

A dog.
---

I like dogs, and dogs like me, but the overhead is too high.

On second thought though, the walks might be worth it.
--

A hot babe who likes me. ;-)

---
I've got that.
---

A drink.

---
I've got that.
---

A doobie.

---
I can get that.
---

A pizza.

---
I can get that.
---

etc., etc., etc.... ;-)

How about:

Objectivity?

Clarity?

Nirvana?

JF

 

[Rich Grise]

On Mon, 03 Nov 2008 18:27:35 -0600, John Fields wrote:

On Mon, 03 Nov 2008 20:44:49 GMT, Rich Grise <rich@example.net> wrote:

A hot babe who likes me. ;-)

I've got that.

Well, I guess you're done! Congrats!

Cheers!
Rich

 

[IanW]

"John Fields" <jfields@austininstruments.com> wrote in message
news:slhpg4128to0i0s3er7c2rhtr8aeh8t61u@4ax.com...

---
Here's a brute force one over on abse that's _guaranteed_ to work:

news:59hpg454qhuls80gbombs7l8jf9lchkd9l@4ax.com

Hi John. Is pin 11 of U1 supposed to go anywhere, only it's not connected in
the diagram and the circuit doesn't work.

Thanks
Ian