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555 timer

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

Reply to
tt
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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

Reply to
Robert Monsen

"tt" damaged to put back up, but the lights work great. I would like each light

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

Charles

Reply to
Charles W. Johson Jr.

On Wednesday 22 September 2004 09:40 pm, Charles W. Johson Jr. did deign to grace us with the following:

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

Reply to
Rich Grise

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
Hobbyist, West Sussex, UK
Reply to
Terry Pinnell

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

--
Terry Pinnell
Hobbyist, West Sussex, UK
Reply to
Terry Pinnell

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

--
Terry Pinnell
Hobbyist, West Sussex, UK
Reply to
Terry Pinnell

Sheesh! 555.

Jon

Reply to
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: snipped-for-privacy@jmwa.demon.co.uk

--
Terry Pinnell
Hobbyist, West Sussex, UK
Reply to
Terry Pinnell

On Friday 24 September 2004 10:50 pm, Terry Pinnell did deign to grace us with the following:

None that are known by me. ;-)

Reply to
Rich Grise

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

Jon

Reply to
Jonathan Kirwan

If you started now and listened to one a day, I reckon you'd finish on

1st April 2005 . 
--
Terry Pinnell
Hobbyist, West Sussex, UK
Reply to
Terry Pinnell

"tt" back up, but the lights work great. I would like each light to come on for

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For a 555 timer solution have a look at

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

Rob.

Reply to
Rob Paisley

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