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Topic: Help with vehicle underglow (Read 2647 times) previous topic - next topic

Imdbtruth

I'm wanting to put addressable underglow on my vehicle using GS8208 strips that I'm ordering direct from China... I hear that the GS8208 strips are more stable than the WS2815 strips, but the GS8208 does not have capacitors and resistors built in to the strip itself like the WS2815 does...

I'm wondering how many capacitors and resistors I will need, and also how I should wire them?

My set up will be like this;

1.8 meter strip on each side of the vehicle with 108 pixels on each side, or 216 total pixels on the sides
1.0 meter strip on both the front and the back of the vehicle with 60 pixels on each strip, or 120 pixels total for the front and back strips
Total length for all of the strips is 5.6 meters and 336 total pixels

Do I need more than one capacitor and/or resistor? What size capacitors and resistors? And where and how should I install said capacitors and/or resistors?

Thank you so much!

PaulRB

You will need one resistor per strip, close to the data-in connection. I think one 470uF for each of the shorter strips, again close to the start of the strip. For the longer strips, 1000uF each or 470uF at each end of each strip. You will need power lines going to the start and end of the longer strips, I suspect, otherwise you might get significant voltage drop along the length of those longer strips.

Lay it out, connect it all up and test thoroughly for 24hrs before fixing to the vehicle!

Paul__B

Note that there must be a ground travelling as a pair with the data connection as it passes from one strip to the next and of course that the supply and ground must always run as a pair.  No separate wires.  Particularly important in a car.

Imdbtruth

Note that there must be a ground travelling as a pair with the data connection as it passes from one strip to the next and of course that the supply and ground must always run as a pair.  No separate wires.  Particularly important in a car.
Thank you so much for your help Paul! But can you please dumb it down even further for me? What do you mean by "ground and data traveling as a pair" and "no separate wires"?


Paul__B

It's basically like the power cables to your appliances - two power wires and a ground are all in the one cable, not as separate wires.

When people show projects her made on "solderless breadboards", they often have a lot of "jumper wires" or "Dupont wires" looping over from one part to another.

For a simple mock-up that may be OK.  But that does not work in any "real-world" situation where there are sources of electromagnetic interference and risks of physical damage.

Separating the two wires of a circuit creates a loop and at the frequencies used in microcontrollers, a loop is an inductor which can couple to another inductor loop and act as a transformer to pick up impulses from one to another, or you can also consider it a radio antenna to transmit and receive.  So you must not form such loops; if two wires travel together, they do not form a loop.

This applies both to power and ground as a pair, or to data and ground as a pair.  These strips have power, data and ground connections, so you must keep all three together.  You cannot just have one of the wires travel cross-country on its own.  So in practice, the power (which means power and ground) must run directly from the power supply to the start of the strip (and also to join in again every metre or so along the strip as the foil on the strip is not capable of carrying all the current) and then the power and data (with the ground) connections run also from the start of the strip where the "data in" connects, back to the Arduino to provide 5 V power to the Arduino and to take the data back to the strip.

Imdbtruth

Thank you for your help! I finally understand what you were talking about... I still haven't done my install, but it won't be long now...

If you don't mind, I have one more question regarding resistors on the data line... Should I put a 330R on just the first strip, as close as possible to the first LED, or should each strip have its own 330R resistor wired into the data line?

Thanks again!

Imdbtruth

Also, I was wrong in my original post when I said the GS8208 strips I'm using don't have capacitors and resistors built in to the LED strip... They actually do have tiny capacitors and resistors on the PCB between each LED pixel...

Knowing that, does that change your recommendation for how to power them as far as using external capacitors and resistors, as well as power injection?

Unordung

Lay it out, connect it all up and test thoroughly for 24hrs before fixing to the vehicle!
Solid advise!

As a side note however, an automotive electrical system is nothing like the electrical systems you're likely used to. You will be subjecting the micro-controller and LED strips to an inhospitable environment.

Huge transients / voltage spikes are possible and likely.
This will take careful planning to avoid and mitigate.

Consider wiring all of the cabling for this well clear of existing wires to prevent cross talk. Add bypass capacitors (0.1uF) to the VCC line of the Micro-controller and the LED strips. This will reduce transients.

You also want to consider a circuit to specifically protect the micro-controller / Arduino from voltage spikes etc.   

PaulRB

#8
May 20, 2020, 09:02 am Last Edit: May 20, 2020, 09:03 am by PaulRB
Should I put a 330R on just the first strip, as close as possible to the first LED, or should each strip have its own 330R resistor wired into the data line?
If the wires between the strips are short (<100mm) you may not need resistors there, but it won't hurt to include them.

They actually do have tiny capacitors and resistors on the PCB between each LED pixel... does that change your recommendation for how to power them as far as using external capacitors and resistors, as well as power injection?
No.

Imdbtruth

#9
May 20, 2020, 09:18 pm Last Edit: May 20, 2020, 09:46 pm by Imdbtruth
Solid advise!

As a side note however, an automotive electrical system is nothing like the electrical systems you're likely used to. You will be subjecting the micro-controller and LED strips to an inhospitable environment.

Huge transients / voltage spikes are possible and likely.
This will take careful planning to avoid and mitigate.
I'm planning on using this Fulree 12V10A Voltage Regulator, which I hope will help stabilize the voltage


Consider wiring all of the cabling for this well clear of existing wires to prevent cross talk. Add bypass capacitors (0.1uF) to the VCC line of the Micro-controller and the LED strips. This will reduce transients.
Where should I place the bypass capacitor, close to the Micro-Controller, or close to the LED strip? And should each LED strip have a bypass capacitor?

I was going to run the 4 pin connectors to each strip, with a 330 Resistor included on the data line of each strip, but also I'm planning to inject power via a 2 pin connector at the beginning of each strip, and a 50V/1000uf capacitor will be wired into the 2 pin line just before the beginning of each strip.

You also want to consider a circuit to specifically protect the micro-controller / Arduino from voltage spikes etc.   
This is a picture of the Blueghozt, it is the Micro-Controller I'll be using, it was designed specifically for vehicles.


Thank you guys so much for the help and advice!

Paul__B



Where should I place the bypass capacitor, close to the Micro-Controller, or close to the LED strip?
Always at the LED strip, otherwise it is useless.

And should each LED strip have a bypass capacitor?
Not a bad idea.  :smiley-lol:

Noting my previous comments that the wires, including those that run parallel to the strip to feed power at multiple points - must be kept bundled together with the strip they are feeding; there should be no loops evident anywhere.

Imdbtruth

#11
May 21, 2020, 04:15 am Last Edit: May 21, 2020, 07:14 pm by Imdbtruth
This is my path of wiring... I'm sorry, I'm even worse at drawing diagrams... Can you please tell me if you spot any loops?

1. Power Directly from Car Battery
2. Fuse
3. Toggle Switch to 12V10A Regulator
4. 12V Regulated output delivered to small positive and negative Bus Bars
5. From the Bus Bars there will be three branches, with one set of power wires running to the Blueghozt Micro-Controller located inside the vehicle...
6.The other two sets of power wires will run from the Bus Bars to outside of the vehicle, where it will feed two separate 6-Way Waterproof 2-Pin Splitters... One Splitter will feed power to the 2-Pin Connectors at beginning of each LED Strip for the left channel, and the other 6-Way 2-Pin Splitter will feed power to the 2-Pin Connectors for power injection on the right channel.
7. The Blueghozt Micro-Controller will take the regulated 12V from the Bus Bars and distribute it to both of its 4-Pin LED channels (technically the Blueghozt has only 3-Pin channel wiring, but it will feed my 4-Pin LED Strips, which have two data lines).
8. The Left and Right channels of the Blueghozt will each feed a 0.72 Meter LED strip in the front, which will connect to a 1.8 Meter LED Strip for the side skirts, which will connect to a 0.72 Meter strip on the rear (3.22 Meters per side/channel, 6.44 Meters of LED strips total for both channels)
9. On the 4-Pin connections, near the beginning of each LED Strip, I will have a 330 Resistor on every Data Line, and also a 0.1uf Bypass Capacitor connected to the Power and Ground Wires on every 4-Pin connection nearest to the beginning of each LED Strip
10. Each 2-Pin Power Injection connection will come from the 6-Way 2-Pin Waterproof Splitters, from the Splitters there will come 6 independent 2-Pin Cables, each one of those 2-Pin cables will connect at the beginning of each of the 6 LED Strips
11. On the 2-Pin connections, near the beginning of each LED strip, I will have 1000uf Capacitors wired into the Power and Ground wires of the 2-Pin Power Injection points

Imdbtruth

Well, I can't blame anybody for not wanting to sift through all that drivel I wrote in my last post, it's asking too much... Maybe if I keep my questions shorter and more to the point...

Regarding the placement of the capacitors, is it okay if I put the 1000uf capacitor on the 2-pin power injection line, and I put the 0.1uf bypass capacitor on the 4-pin line (along with the 330 resistor that will be on the data wire of the 4-pin line)?

PaulRB

#13
May 23, 2020, 09:47 pm Last Edit: May 23, 2020, 09:49 pm by PaulRB
... I put the 0.1uf bypass capacitor on the 4-pin line (along with the 330 resistor that will be on the data wire of the 4-pin line)?
Not sure what use those 0.1uF bypass caps will be, although I'm fairly sure they won't be harmful. You seem to be distinguishing 2 pin and 4 pin lines. Not sure what the difference is. Aren't they all 3-pin lines?

I think the main reason for the delay in responding is that we all realised this is not an Arduino project.

Imdbtruth

Not sure what use those 0.1uF bypass caps will be, although I'm fairly sure they won't be harmful.
I'm also not sure what is the purpose of the 0.1uF bypass capacitors... I only said that because the other respondent said "Add bypass capacitors (0.1uF) to the VCC line of the Micro-controller and the LED strips." VCC is the power connection, right?

You seem to be distinguishing 2 pin and 4 pin lines. Not sure what the difference is. Aren't they all 3-pin lines?
Well, like the controller only has 3 output wires per channel, but the LED strips have 4 input/output wires, because it has an extra wire for the backup data line.

The 2-pin line is kind of the same as the 4-pin line, because it's soldered into the same +/- pads on the LED strip as the 4-pin line uses. The "2-pin line" is just for power injection, I have both a 2-pin and a 4-pin connector at the beginning and end of every strip for injecting more power.


I think the main reason for the delay in responding is that we all realised this is not an Arduino project.
I do apologize for deviating from the primary focus of the forum. It's just that it's hard to find good technical advice regarding addressable LED strips, and I knew that this place was probably my best bet for getting help from people who are very smart and knowledgeable about such things.

I just want to do it the best way possible... I want to do it the way somebody who actually knows what they're doing would do it.

I sincerely appreciate any help that is offered! I'm also trying to learn some for myself, I've been watching YouTube videos on circuits, and capacitors, and resistors, and loops, but I still don't understand well enough to really know for myself.

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