555 timer

[tt]

I am trying to construct a simple device for turning on and off three lights
(one at a time). I have a traffic light that was blown down during a recent
hurricane (obtained from the road dept.). It's frame was too damaged to put
back up, but the lights work great. I would like each light to come on for
a period then go out and the next light come on. I was thinking of using a
555 timer because several years ago I managed to construct a wavemaker
device for my fishtank that alternates power to two pumps creating a nice
water current. That device is still working like a champ today.

I looked at the plans for that wavemaker and I don't think it will do
because I am trying to activate three items and not two. Can anyone suggest
a solution?
Thanks!
Todd

 

[Robert Monsen]

I am trying to construct a simple device for turning on and off three lights
(one at a time). I have a traffic light that was blown down during a recent
hurricane (obtained from the road dept.). It's frame was too damaged to put
back up, but the lights work great. I would like each light to come on for
a period then go out and the next light come on. I was thinking of using a
555 timer because several years ago I managed to construct a wavemaker
device for my fishtank that alternates power to two pumps creating a nice
water current. That device is still working like a champ today.

I looked at the plans for that wavemaker and I don't think it will do
because I am trying to activate three items and not two. Can anyone suggest
a solution?
Thanks!
Todd

You can make the 555 pulse into 3 separate pulses using a 4017 chip. The
datasheet shows how to set it up so when the third pulse ends, it starts
over again.

You probably will need some kind of power transistor to power the
lights; the 4017 won't power them. However, the fishtank thing probably
had the same issues, so this may not be a problem for you.

Regards,
Bob Monsen

 

[Charles W. Johson Jr.]

I am trying to construct a simple device for turning on and off three
lights (one at a time). I have a traffic light that was blown down during
a recent hurricane (obtained from the road dept.). It's frame was too
damaged to put back up, but the lights work great. I would like each light
to come on for a period then go out and the next light come on. I was
thinking of using a 555 timer because several years ago I managed to
construct a wavemaker device for my fishtank that alternates power to two
pumps creating a nice water current. That device is still working like a
champ today.

I looked at the plans for that wavemaker and I don't think it will do
because I am trying to activate three items and not two. Can anyone
suggest a solution?
Thanks!
Todd

A 555 and a three digit shift register. each pulse of the 555 shift the
output by one.

Charles

 

[Rich Grise]

A 555 and a three digit shift register. each pulse of the 555 shift the
output by one.

Actually, either 3 x 555 in a daisy-chain, or a counter and some selector
logic, so that it'll be green for, say, 10 seconds, yellow for 1.5, and
red for 15, and so on.

Just have the falling edge of each 555's output trigger the next one,
with the third looped around to the first.

You would need some kind of startup logic and "forbidden state" prevention,
but it sounds like a fun project.

Good Luck!
Rich

 

[Terry Pinnell]

Actually, either 3 x 555 in a daisy-chain, or a counter and some selector
logic, so that it'll be green for, say, 10 seconds, yellow for 1.5, and
red for 15, and so on.

Just have the falling edge of each 555's output trigger the next one,
with the third looped around to the first.

You would need some kind of startup logic and "forbidden state" prevention,
but it sounds like a fun project.

Good Luck!
Rich

THREE 555s (plus associated RC sections etc) to light three lamps!?

Bob's 555 (or any other simple clock generator) plus 4017 approach
seems the obvious solution. Not only cheap and simple, but also
flexible. It could allow gaps if desired between lighting, and/or
different durations of the three colours, within the limit of 9 active
outputs.

 

[Terry Pinnell]

THREE 555s (plus associated RC sections etc) to light three lamps!?

Bob's 555 (or any other simple clock generator) plus 4017 approach
seems the obvious solution. Not only cheap and simple, but also
flexible. It could allow gaps if desired between lighting, and/or
different durations of the three colours, within the limit of 9 active
outputs.

P.S: Can you guess how many harpsichord sonatas are known to have been
written by Scarlatti?

 

[Terry Pinnell]

THREE 555s (plus associated RC sections etc) to light three lamps!?

Bob's 555 (or any other simple clock generator) plus 4017 approach
seems the obvious solution. Not only cheap and simple, but also
flexible. It could allow gaps if desired between lighting, and/or
different durations of the three colours, within the limit of 9 active
outputs.

BTW (straying slightly OT), can you guess how many harpsichord sonatas
are known to have been written by Scarlatti?

 

[Jonathan Kirwan]

BTW (straying slightly OT), can you guess how many harpsichord sonatas
are known to have been written by Scarlatti?

Sheesh! 555.

Jon

 

[Terry Pinnell]

Sheesh! 555.

Jon

Correct - you win the prize!

In fact, I'm able to pass on this one to you, which I was proud to
receive a few days ago:

 

[Rich Grise]

BTW (straying slightly OT), can you guess how many harpsichord sonatas
are known to have been written by Scarlatti?

None that are known by me. ;-)

 

[Jonathan Kirwan]

Correct - you win the prize!

In fact, I'm able to pass on this one to you, which I was proud to
receive a few days ago:
news:[email protected]

Thanks, Terry. I can see you were _fishing_ for just such an opportunity, too!


Jon

 

[Terry Pinnell]

None that are known by me. ;-)

If you started now and listened to one a day, I reckon you'd finish on
1st April 2005 <g>.

 

[Rob Paisley]

I am trying to construct a simple device for turning on and off three lights
(one at a time). I have a traffic light that was blown down during a recent
hurricane (obtained from the road dept.). It's frame was too damaged to put
back up, but the lights work great. I would like each light to come on for
a period then go out and the next light come on. I was thinking of using a
555 timer because several years ago I managed to construct a wavemaker
device for my fishtank that alternates power to two pumps creating a nice
water current. That device is still working like a champ today.

I looked at the plans for that wavemaker and I don't think it will do
because I am trying to activate three items and not two. Can anyone suggest
a solution?
Thanks!
Todd

--------------------------

For a 555 timer solution have a look at

http://home.cogeco.ca/~rpaisley4/LM555.html#24

A suitable driver will be needed for the lamps as well.

Rob.