Daisy Chain LED Strip

[Yogar67]

Hi,

Is it possible to daisy chain RBG LED strips? (Like these - https://www.amazon.co.uk/dp/B01KHWGVJ4)

I have 2 x 60 LED strips that I would like to join together to make a single 120 LED strip but I can't see how to do it.

Thanks for your help

[bcochran1]

Hi,

If the NeoPixel strips you have are truly Adafruit products, you should be able to connect them together. You need to go to the Adafruit product description and read that, then read the "NeoPixel Uber Guide" for the details of how to connect them together, provide power to them and program them.

If they are not Adafruit products, you will have to ask your vendor for assistance. The link you provided seems to imply you purchased an Adafruit NeoPixel strip, product #1138. However I'm not sure if you have a similar LED strip which was not sourced from Adafruit.

Please note, I am not an employee of Adafruit. I'm just another forum member trying to help you.

I suggest reading the Uber Guide not just once, but several times, and following it's advice if indeed you have Adafruit products.

One last thing: you can post photos of your products in this thread. It would be helpful if you do. Try to post very clear photos of the two ends of each LED strip that you have, plus a closeup photo of a part of the strip that shows the LED's face up.

Thanks so much

Bob

[Yogar67]

Hi Bob

Thanks for your reply. I have purchased genuine Adafruit LED strips from The Pi Hut (via Amazon) - see attached receipt. I have managed to successfully connect a single strip to a Raspberry Pi and got it working using the Adafruit Raspberry Pi Wiring guide https://learn.adafruit.com/neopixels-on ... -pi-wiring and the sample Python code https://learn.adafruit.com/neopixels-on ... thon-usage.

I have also found and read the Adafruit NeoPixel Überguide however, although this implies that strips can be joined, it doesn't tell you how to do it.

The link within the guide to the strip page https://www.adafruit.com/product/1138?length=1 says "of course, you can also connect strips together to make them longer" but again does not say how.

See photo - one end of each stip has wires (eg for connecting to Pi) whereas the other end is blanked-off and it doesn't appear that the end piece is designed to be removed. I didn't want to force it off in case I broke something.

I'm hoping this is straightforward and does not require any cutting and soldering. This is just for a little project to attempt to get my 12 year old daughter interested in programming.

Thanks again for any insight you may have.

[bcochran1]

Hi,

You are going to have to do at least some cutting and soldering, I think. Can you post a new photo that clearly shows the inside of each of the black connectors? I'm trying to determine whether one connector will fit into the other. That connector carries your signal to the LED "pixels". The two loose wires are 5v (the red wire) and GND (the black wire...ground or earth.)

I would also like to see a picture showing a section of each strip near the connectors. I am looking for the arrows that show the direction of data flow on each strip. If you look closely at the pixels on the strip, you will see arrows printed on the flexible circuit board. I want to be sure that if the connectors are able to plug together, the arrows on both strips all point in the same direction.

In my mind one of the strips will have to be cut and 3 wires soldered to the pixel at the very end, such that +5V, ground, and signal can all flow from the microcontroller and the separate power source to each pixel in the two strips, following the direction of the printed arrows.

I myself have never connected 2 NeoPixel strips together. I do in fact have two NeoPixel strips available to me. I'll work on connecting them together and report back to you when I can. For me it will be easier, because at least one of my NeoPixel strips has signal connectors at both ends, but I will need to use a terminal block (or two separate Wago connectors) for the power and ground wires.

I have also thought of suggesting you just use an 8-pixel LED bar (also from Adafruit), which is a lot more compact. The LED bar requires soldering work too. I'll post photos later.

Thanks so much

Bob

[Yogar67]

Hi Bob

Pictures of the pixels and blanked-off end

Thanks

Gary

[Yogar67]

Hi Bob

Photos of the wired end connector.

Thanks

Gary

[bcochran1]

Hi!

So, I'm moving a little slowly here. I observe that your strips have very nice 3 pin JST SM connectors: data, 5v power, and ground. My much older strips only have 2-pin connectors: signal only. There are separate power and ground wires for me to connect. That is okay.

Here are two annotated photos of Neopixel strip #1 showing the end that connects to my ItsyBitsy M4 Express.

power_to_neopixel_strip_1_2020-01-08_small.jpg (240.93 KiB) Viewed 407 times

To feed power to the strip I am using a 10 amp, 5v power brick. It plugs into a 2.1mm inside diameter female connector-to-screw-terminal adapter, and from the screw terminal side I run +5v and GND wires to the breadboard that the ItsyBitsy is plugged into. A separate set of power and ground wires run from the breadboard power rails to the power and ground wires on this Neopixel strip. I probably ought to use Wago connectors to distribute power to the breadboard and to the Neopixel strip separately.

neopixel_strip_1_power_and_data_small.jpg (204.96 KiB) Viewed 407 times

This close up of NeoPixel strip #1 shows the direction that the data will flow in.

This strip is terminated in a 2-pin JST SM connector for the data line and 2 wires for power and ground.

Now that we see what Strip #1 is like, we can move on and connect strip #2 to strip #1. For me, this will be pretty easy. Strip #2 has a 2-pin connector for the signal, and 2 wires for power and ground. I plan to plug in the JST connectors, and provide a power and ground connection using a terminal block. I could use Wago connectors as well, but I have some new terminal blocks I want to play with.

Once the physical connections are made, I have to upload an updated "strandtest" program for a count of 120 pixels across the 2 strips: 60 pixels in strip 1 + 60 pixels in strip 2 = 120.

I will say more soon...

Thanks so much

Bob
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[bcochran1]

Hi,

I connected my two strips together like so:

neopixel_both_strips_connected_2019-01-10_small.jpg (163.82 KiB) Viewed 387 times

And they work fine. The JST SM connectors are for the signal ("data".) They plugged together together fine. The terminal block is connecting 5v power (red wire) and GND (black wire.) I purchased this terminal block through Amazon. It is a little bulky, but it is rated to 600v, and has a cover to keep little kids from touching anything live. With that said, I wonder if Wago connectors can give a more compact, neater connection.

Here is a close up.

neopixels_2_strips_connected_small.jpg (218.88 KiB) Viewed 387 times

Let's take a look at the direction of data flow for Neopixel strip #2:

strip_2_data_direction_2019-01-10_small.jpg (208.26 KiB) Viewed 387 times

I'm still not sure if you will need to cut one of your strips and do some soldering to get both strips set up with the correct data direction, and of course power and ground. Don't forget the 470 ohm resistor. You have a nice 3-pin connector that will carry power, ground, and signal for you. Perhaps if your really must do any soldering -- you can buy 3-pin connector sets and do a neater connection job than I have. Good luck!

Thanks

Bob

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[Yogar67]

Thanks so much for the effort you have put-in to help me on this Bob.

I will have a go over the weekend and I'll let you know how I get on.

Thank you again

Gary

[bcochran1]

Hi!

Yesterday I started thinking that an Adafruit Circuit Playground Express device might be exactly the right choice for both you and your daughter.

• Fits in your hand easily
  Has 10 NeoPixels on board that can be programmed to any color
  No soldering at all!
  Easy to program using CircuitPython
  Can do a bunch of other things too.

I hope this suggestion helps you. I was going to post a photo of my ItsyBitsy running an 8 NeoPixel light bar, but the trouble is it involves a lot of soldering. You'd have to solder headers onto the ItsyBitsy and then wire pigtails onto the NeoPixel light bar. Also I have it set up to use a lithium polymer battery. That adds an extra device and wiring with additional soldering.

Then I realized that a Circuit Playground Express would be just the thing. You take it out of the bag, update the version of CircuitPython on it, get the latest version of the Mu editor and start playing -- or you can use MakeCode if you prefer. No need to fuss about resistors or capacitors, the on-board pixels are set up with the correct hardware. The Circuit Playground Express lets you zero in on the coding experience and getting the result in a fuss-free, simple way.

I'm starting to sound like an Adafruit advertisement, so I'll be quiet.

Thanks so much

Bob