Are you going to run cable out to each light from controller or
use a single cable with taps for each light. The latter uses a
chip / light, addressable, to turn on/off, and brightness level.

https://cdn-shop.adafruit.com/datasheets/WS2811.pdf

You would have a simple host interface, a UP, sending out
address and data for each LED light.

This chip is used extensively in led lighting strips. 10M light
to light distance allowed. Programming of host to this serial
network fairly simple, libraries already exist for Arduino.

Note chip has RGB capability, but you could use it just to
turn on/off the light its connected to.

Just a thought.


Regards, Dana.

The fixtures I am using would require a separate cable to each unit. They have a DMX version, but it's really pricey. Thanks.

 

This is how to cascade the CD4017:
View attachment 169259

Thanks! I'm going to give this a shot. I won't have much invested and for my purposes, it's the cleanest solution. The only thing I'm not clear on with this is the reset loop. If, for example, I only end up with 25 fixtures with four cascaded 4017(s) how do I loop at event 26?

 

The AND gate might be CD4081BC.

Thank you.

 

If, for example, I only end up with 25 fixtures with four cascaded 4017(s) how do I loop at event 26?

You connect the output for event 26 (Q2 of the last 4017) back to the reset of the first 4017.

 

This is how to cascade the CD4017:
View attachment 169259

This is probably the best place to start. I forgot that the 4017 is a decoded Johnson counter and was assuming that it was a shift register.

That circuit ensures that it will never stall and will be self-recovering from any upset.

 

Here is a shot at what might work.View attachment 169361 Out of time. Game over; time now to rotate image.
Not sure in what state ckt. comes up at power up, but if needed could add NOR gate
to U2-15, reset to one input, RC delay to other input ?

 

If you have long cable runs need to think about inductive effects and
reflections on both ends of the cable. "Normally" that is handled by
differential drivers, or current loop. But you can do a test, using scope,
and clamps on each end.

Clamp looks like -

Regards, Dana.

 

You connect the output for event 26 (Q2 of the last 4017) back to the reset of the first 4017.

I assumed that, but glad for the confirmation Thanks

 

View attachment 169376 Here is a shot at what might work.View attachment 169361 Out of time. Game over; time now to rotate image.
Not sure in what state ckt. comes up at power up, but if needed could add NOR gate
to U2-15, reset to one input, RC delay to other input ?

Thanks. Time to breadboard.

 

If you have long cable runs need to think about inductive effects and
reflections on both ends of the cable. "Normally" that is handled by
differential drivers, or current loop. But you can do a test, using scope,
and clamps on each end.

Clamp looks like -

Regards, Dana.

Longest cable run would be less than 15 feet, so that could be a factor for the fixtures on the ends. Thanks.

 

Late to the party, but I like the cascaded 4017 approach over the other options presented.

OTOH ...

Another option is a CD4060 driving two CD4514 4line-to-16line decoders. Only 3 chips total, more accurate and more stable timing (32x smaller timing capacitor), and one small transistor does all of the device gating. As with the 4017 approach, jumpering any output to the counter reset terminates and the sequence at that stage and restarts at output #1.

Not mentioned yet are the (up to) 30 external power transistors or driver stages, one for each LED. If switching the LEDs to GND is allowed, four ULN2804's might do this since only one stage is on at a time.

ak

 

Late to the party, but I like the cascaded 4017 approach over the other options presented.

OTOH ...

Another option is a CD4060 driving two CD4514 4line-to-16line decoders. Only 3 chips total, more accurate and more stable timing (32x smaller timing capacitor), and one small transistor does all of the device gating. As with the 4017 approach, jumpering any output to the counter reset terminates and the sequence at that stage and restarts at output #1.

Not mentioned yet are the (up to) 30 external power transistors or driver stages, one for each LED. If switching the LEDs to GND is allowed, four ULN2804's might do this since only one stage is on at a time.

ak

Your approach sounds interesting size is definitely a factor since I have no way to hide any enclosure. As far as drivers, those are integrated into the fixture, I just need to switch +12VDC . As I mentioned to someone earlier, I'm knowledgeable enough to understand what people are explaining and I'm a decent fabricator, but if you have a moment to sketch and scan a schematic of your approach, it would really help me. Thanks.

 

Here is something that is better than 30 555's in series. R1+R2 set the time period (along with C1), and can be replaced by a group of fixed resistors and switches. The dangling wire in the upper right corner is the RESET connection that restarts the sequence. Connect it to the output above the last one used. For example, if you have 25 outputs driving LED's, connect the reset line to OUT-26.

Note - there should be three decoupling caps. oops.

ak

 

Here is something that is better than 30 555's in series. R1+R2 set the time period, and can be replaced by a group of fixed resistors and switches. The dangling wire in the upper right corner is the RESET connection that restarts the sequence. Connect it to the output above the last one used. For example, if you have 25 outputs driving LED's, connect the reset line to OUT-26.

Note - there should be three decoupling caps. oops.

ak
View attachment 169421[/
Outstanding! I will be anxious to give this a try. Thank you!

 

Is there any chance that C3 will swamp out a 4514 output or do we need an OR gate for reset?

 

If you mean C2, the reset capacitor, a 4 mA CMOS output will charge it up to 7 V in around 0.6 ms.

The circuit posted is an edit of something for another thread on another forum. The 0.33 uF value is left over from that design, which had that specific value somewhere else so I used it for decoupling and reset for parts commonality. C2, C3, and the two missing decouplers (C4 and C5) all can be 0.1 uF.

ak

 

You could considered using a Programmable Logic Device such as as the EPM570 (ALTERA MAXII) with the shift register ideas of the other replies. They have a very large number of inputs / outputs and you can build up a complex logic gate system in it to do your job (including a timer), and reprogram it to your hearts content.
The chip and programmer can be bought very cheaply from china, and there is a freeware version of the software. There are also some good videos on youtube for a quick guide for getting into programming them.

 

You could considered using a Programmable Logic Device such as as the EPM570 (ALTERA MAXII) with the shift register ideas of the other replies. They have a very large number of inputs / outputs and you can build up a complex logic gate system in it to do your job (including a timer), and reprogram it to your hearts content.
The chip and programmer can be bought very cheaply from china, and there is a freeware version of the software. There are also some good videos on youtube for a quick guide for getting into programming them.

Good thought. Thanks!

 

You could considered using a Programmable Logic Device such as as the EPM570 (ALTERA MAXII) with the shift register ideas of the other replies. They have a very large number of inputs / outputs and you can build up a complex logic gate system in it to do your job (including a timer), and reprogram it to your hearts content.
The chip and programmer can be bought very cheaply from china, and there is a freeware version of the software. There are also some good videos on youtube for a quick guide for getting into programming them.

I'm a huge fan of CPLDs and small FPGAs, but I think they are overly complex for this project.

I am interested in what you are saying. Please post links to the China devices, software, and videos.

ak

 

No problem.. I had to have a crash course in them myself as I wanted to build a high speed counter. The software takes a bit of finding your way around but there are lots of videos on youtube to help. A couple of links for you:

https://www.aliexpress.com/item/5pc...80.html?spm=a2g0s.12269583.0.0.75f122adDUw8FZ

https://www.aliexpress.com/item/USB...870.html?spm=a2g0s.9042311.0.0.27424c4d1vi2zP

You can also buy "break out boards" for the EPM570T.. but with places like PCBway having 2 layer PCBs 10cm x10cm for $5 you may as well be brave and go straight to a PCB!