Lighting for street sign

[piers]

I bought a pedestrian walk/dont walk streetsign at a boot fair, Im putting in twoGU10 led lights. Is there an automatic switch I can make that will alternate between the two bulbs so one is on and then the other alternately, changing automatically every 20 seconds or so? Any advice appreciated, thanks.

 

[Harald Kapp]

See e.g. this module.

 

[kellys_eye]

Great link Edd

(but are the outputs synchronised???)

 

[piers]

See e.g. this module. That looks exactly what I need, many thanks,

 

[Harald Kapp]

Great link Edd

Edd?

 

[Harald Kapp]

are the outputs synchronised

Looks like the outputs alternate and one can adjust the on time for each output individually.

 

[kellys_eye]

Edd?

LOL - sorry. Don't know what made me do that (other than age)!

Problem wit individual output settings is that it's almost impossible to set them they don't eventually go out of sync and overlap. The way to go would be to use one output to drive a relay with c/o contacts and connect the two lamps to the outputs of that relay.

 

[piers]

Looks like the outputs alternate and one can adjust the on time for each output individually.
View attachment 60106

Looking at the customer videos in the reviews for the amazon listing shows people using this for exactly the same purpose Im after. Thanks for the help

 

[AnalogKid]

LOL - sorry. Don't know what made me do that (other than age)!

Problem wit individual output settings is that it's almost impossible to set them they don't eventually go out of sync and overlap.

That is not how it works. The circuit is, effectively, two monostables in series in a circle. The end of each one's pulse triggers the other one. The output pulses cannot overlap in any circumstance. If you want to build one, I would use a CD4093 for the monostables (two gates each) and two sensitive-gate TRIACS.

Getting an exact 50/50 duty cycle requires tweaking both adjustments, and changing the overall cycle frequency also requires changing both adjustments.

ak

 

[bidrohini]

What about switching two loads with an Arduino and a relay?

 

[Harald Kapp]

The way to go would be to use one output to drive a relay with c/o contacts and connect the two lamps to the outputs of that relay.

Allow me to disagree: The two outputs should be active alternatingly. What you set is the on-time individually for each output.
Thus:
output one is active for time 1
output 1 goes inactive, output 2 becomes active and stays active for time 2
output 2 goes inactive, output 1 becomes active and stays active for time 1
etc. etc.

No way the two outputs can run out of sync.

 

[Harald Kapp]

Getting an exact 50/50 duty cycle

I doubt this is a requirement. For a pair of alternting traffic lights "almost 50/50" should be good enough.

What about switching two loads with an Arduino and a relay?

I don't think that is within easy reach for the op.