Multiple breathing LED chaser circuit

Thread Starter

bmcc339

Joined Nov 13, 2023
8
Hi everybody, I’m very new to electronics - trying to make a breathing LED chaser circuit with different colored LED’s. I was hoping somebody could help me understand how this might be constructed.

I want to wire 4 5mm LED’s (red, green, blue, yellow) to breathe in sequence - red breathes, then green breathes, then blue, then yellow, then back to red, and the sequence repeats. I’d also like to have a potentiometer which controls the speed of the breathing across all 4 LED’s.

Is this possible with a 555, or would I need a more advanced component? Would each LED need its own 555? I haven’t been able to find what I’m looking for so I thought I’d try here. Again, there are massive gaps in my knowledge of circuitry. Thanks in advance.
 

Sensacell

Joined Jun 19, 2012
3,401
"Breathing" is not really specific enough to comment on a design concept.
Create a diagram better defining what you want it to do.
 

ElectricSpidey

Joined Dec 2, 2017
2,756
Of course, right off hand most members here will say use a micro, and that would be the simplest way.

But I can imagine a circuit with the following components.

1 555
1 Op-Amp
1 Transistor
1 4017
1 load driver chip
And some misc. components...the pot etc.

Basically, the Op-Amp would be connected to the timing cap of the 555 in follower mode to provide the breathing with a high side transistor. (the pot will also be configured on this 555)

Then each LED will be connected to the load driver driven by the outputs of the 4017. (providing the low side connections)

The output of the 555 will clock the 4017.

Unfortunately, I am not at my PC where I can create a schematic, but I just wanted to put out this concept if you are interested.
 

Thread Starter

bmcc339

Joined Nov 13, 2023
8
"Breathing" is not really specific enough to comment on a design concept.
Create a diagram better defining what you want it to do.
I’ve made a few single LED breathing circuits using this basic model. I’d like to have 4 individual LED’s breathing (not just switching) in sequence. One fades in and out, the next one fades in and out, etc.
 

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Thread Starter

bmcc339

Joined Nov 13, 2023
8
Of course, right off hand most members here will say use a micro, and that would be the simplest way.

But I can imagine a circuit with the following components.

1 555
1 Op-Amp
1 Transistor
1 4017
1 load driver chip
And some misc. components...the pot etc.

Basically, the Op-Amp would be connected to the timing cap of the 555 in follower mode to provide the breathing with a high side transistor. (the pot will also be configured on this 555)

Then each LED will be connected to the load driver driven by the outputs of the 4017. (providing the low side connections)

The output of the 555 will clock the 4017.

Unfortunately, I am not at my PC where I can create a schematic, but I just wanted to put out this concept if you are interested.
This is incredibly helpful, thank you!
 

Ya’akov

Joined Jan 27, 2019
8,976
Given the ready availability, low cost, and amazing flexibility of some components today, my approach would most certainly be using a μC and WS2812B addressable LEDs or equivalents.

For the μC, I would use an AVR ATTiny85 (~$2.00 each in small quantities). It is an 8-pin package, either DIP for through-hole or a tiny SMD package. Only a bypass capacitor is needed to make a programmed ATTiny operate.

For the LEDs you can choose from versions of individually addressable RGB(W) LEDs that have packages ranging from standard T5, vanilla 5mm LEDs to SMD devices as small as 2020 up to “standard” 5050 sized parts as found on most LED strips. And, PCB mounted versions are also an option from strips (flex PCB) which can be cut to arbitrary length to individual, tiny, circular PCBs with single 5050 parts mounted.

These LEDs can produce a gamut of arbitrary colors, or be used for the R, G, B, and W chips built into them as individual “pure” colors.

Programming the ATTiny85 for this application is made very simple by strong support in the Arduino IDE including both excellent MCU core support and a choice of very good libraries for using individually addressable LEDs of the many types you might choose (e.g. WS28nn and APA102, among many others).

There is a learning curve, obviously, but though the very start is somewhat steep, it gets much easier—and the power of software revisions compared to hardware is such a great advantage it is well worth the effort.

I don’t know why you might be trying to avoid an MCU solution, but it is rarely justifiable on grounds other than “I don’t want to do that”, with which no argument can be made, or course. But, if it’s because of ignorance, or past difficulties, I would strongly encourage you to give it a go for the few dollars it will all cost you—the benefits of success are enormous. You will be acquiring an amazing tool for this and so many other things.
 

Thread Starter

bmcc339

Joined Nov 13, 2023
8
I’m merely a hobbyist at the moment - what you’re suggesting is way over my head. I’ve only built 2 simple LED circuits with basic components thus far. I don’t have a reason for doing it any particular way because I don’t really know what I’m doing yet. The only priority for this circuit is space. The circuit I want to build will have to fit inside a very small enclosure.
 

ElectricSpidey

Joined Dec 2, 2017
2,756
Ok, here is the more versatile version (allowing brighter LEDs)

R2 will be replaced with the pot and a series resistor. (for the speed control)
The driver chip will be selected as the 7-channel version and depending on the voltage you are going to use.
Basic BOM is...
1 555
1 4017
1 741 op-amp
1 Load driver (to be determined)
1 222 transistor
2 standard diodes
1 capacitor
various resistors
4 LEDs
Power Supply
Proto Board, enclosure...etc.

NOTE: power supply connections are not shown on the 4017.

1699983062504.png

1699983153759.png

Working on a simpler version...will post when done.
 
Last edited:

MisterBill2

Joined Jan 23, 2018
17,853
"Breathing" is not really specific enough to comment on a design concept.
Create a diagram better defining what you want it to do.
Or at the very least, give us a description of LED intensity versus time, since none of the LEDs that I have seen were able to breath. That is a totally non-technical description for an artistic perception of some sort of action. TOTALLY WASTED as to containing any useful information.
 

Thread Starter

bmcc339

Joined Nov 13, 2023
8
Ok, here is the more versatile version (allowing brighter LEDs)

R2 will be replaced with the pot and a series resistor. (for the speed control)
The driver chip will be selected as the 7-channel version and depending on the voltage you are going to use.
Basic BOM is...
1 555
1 4017
1 741 op-amp
1 Load driver (to be determined)
1 222 transistor
2 standard diodes
1 capacitor
various resistors
4 LEDs
Power Supply
Proto Board, enclosure...etc.

NOTE: power supply connections are not shown on the 4017.

View attachment 307535

View attachment 307536

Working on a simpler version...will post when done.
Thank you for this! My knowledge is very limited and I appreciate you taking the time to help. Now I need to go learn what an op amp, a 4017, and a load driver actually do…
 

Thread Starter

bmcc339

Joined Nov 13, 2023
8
Or at the very least, give us a description of LED intensity versus time, since none of the LEDs that I have seen were able to breath. That is a totally non-technical description for an artistic perception of some sort of action. TOTALLY WASTED as to containing any useful information.
I’m all set, thanks bud.
 

Icanmakeit67

Joined Sep 23, 2018
70
Of course, right off hand most members here will say use a micro, and that would be the simplest way.

But I can imagine a circuit with the following components.

1 555
1 Op-Amp
1 Transistor
1 4017
1 load driver chip
And some misc. components...the pot etc.

Basically, the Op-Amp would be connected to the timing cap of the 555 in follower mode to provide the breathing with a high side transistor. (the pot will also be configured on this 555)

Then each LED will be connected to the load driver driven by the outputs of the 4017. (providing the low side connections)

The output of the 555 will clock the 4017.

Unfortunately, I am not at my PC where I can create a schematic, but I just wanted to put out this concept if you are interested.
I’m not the original asking person but I’d love to see this circuit. Thank You
 
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