Serial LED Strip

[dubiousSwain]

Our team has researched our driver feedback options and have decided that we want to use something like this: https://www.adafruit.com/product/306

This is a serial LED strip with individually addressable LEDs, but it has weatherproofing which we don't need. I was wondering if anyone had found and used a similar strip for a cheaper price.

Has anyone used this strip in the past and had problems? Has anyone found anything cheaper?

[seg9585]

We're using this exact same strip this year and it's awesome! We've found cheaper alternatives for LED strips that are not individually addressable but still RGB. After creating the circuit with MOSFETs, the price isn't that much cheaper.

[Breadbocks]

My experience is that you won't be able to find much cheaper from American sellers. However, if you're willing to wait a while or pay a decent amount for expedited shipping, the Chinese option is huge savings on orders of more than a few meters. Adafruit's price for addressables is $30/meter, with 30 leds/m. A quick peek over to Aliexpress shows that $30 will get you 5 meters of 60 leds/m, with the caveat of 10-15 days on the free shipping. An extra $20-30 will get them to you in 3-7 days which is usually quick enough.

Definitely do some research into alternatives. Adafruit is a well known brand with a pretty strong hold on the domestic market for LEDs/strips. A few of the keywords to know are "5050 RGB" which indicates the size of the LED chip, as well as "addressable" which is the term for strips which let you control individual LEDs. You also may encounter "IPXX", most commonly IP67, which is a standard for waterproofing. Most strips will either be not waterproofed, or have that silicon coating that makes them a little awkward to work with, but makes them extremely water resistant for any FRC-related purposes.

[electroken]

Originally Posted by dubiousSwain

Our team has researched our driver feedback options and have decided that we want to use something like this: https://www.adafruit.com/product/306

This is a serial LED strip with individually addressable LEDs, but it has weatherproofing which we don't need. I was wondering if anyone had found and used a similar strip for a cheaper price.

Has anyone used this strip in the past and had problems? Has anyone found anything cheaper?

The "weatherproofing" for the strip in your link is a rectangular section silicone rubber sleeve slid over the strip. It can be cut off with scissors easily or slid off with patience and multiple hands.

[Al Skierkiewicz]

This is the product many teams have used for several years. Search here on CD and you will find a lot of hints and some software. We use it in some form every year.

[RyanN]

You'll need a separate controller besides the RoboRIO to control them unless you want to really dig into the RoboRIO's FPGA subsystem to get the timing control you need to control these.

However, a simple Arduino would work.

[Cinnamon Toast]

Any reason that you're not using the NEOpixel line by adafruit?

https://www.adafruit.com/products/1376

I've used these ones before and they're pretty nice. I've got an arduino on the robot connected to the relay pins on the roboRIO for triggers. If you want code for that PM me.

[Breadbocks]

Originally Posted by Cinnamon Toast

Any reason that you're not using the NEOpixel line by adafruit?

https://www.adafruit.com/products/1376

I've used these ones before and they're pretty nice. I've got an arduino on the robot connected to the relay pins on the roboRIO for triggers. If you want code for that PM me.

This is something I meant to touch on in my other post and missed.

WS2812 (branded by Adafruit as "Neopixel") and LPD8803/LPD8806. These are the chips which allow your LEDs to be addressed individually. Regular single-color or RGB strips don't have these, and they're part of why addressable strips are so much more expensive.

WS2812 are cheaper and more compact. They place a tiny little control chip inside of the LED module which takes the signal in the wire, instead of going directly to the LEDs. They function through a +5v wire, a data wire, and a ground wire going in and out of each chip. The way data is sent to them is a little funky, because it's incredibly clock dependent with no way to mitigate problems, beyond breaking strips up. You will need a separate full-fledged arduino just for driving them, to ensure your clock isn't off.

[Technical Stuff] They transmit signals by having logic highs and logic lows with different square pulse lengths, rather than anything sane. They transmit the full number of one color for the whole line, 8 bits per color per LED on the strip, then the next full set of color data, then the last. Each chip takes its 24 bits off the front of the signal line, then passes the rest on to the next chip. It goes this way until it gets to the end of the line, where bad things happen if the number of bits doesn't add up to the number of chips. Then, it transmits a 50 microsecond reset pulse and starts over again, with potentially different values. This effectively makes it very, very sensitive to being even a tiny bit off on clock speed.

LPD8803 or LPD8806 strips work a bit different. The chips are actually separate from the LEDs, and are significantly more reliable, but cost way more and look a little funny up close because you have random black rectangles on your light strip. The 8803 vs 8806 thing is just the number of LEDs it can support, either 1 or 2 per chip. The upside to the huge price jump is that they're significantly smarter. They get 4 wires in and out. V+, GND, and then a Data and Clock wire. They're standard serial interface, which means they may be more workable on a RoboRio-based solution.

The big tradeoff between the two is reliability vs cost.

[dubiousSwain]

Originally Posted by Breadbocks

This is something I meant to touch on in my other post and missed...(snip)

Thank you for this. I have been looking for this information all night.

To answer Mr. Toast, I didn't buy that because I was looking for something cheaper. I found this on sale on amazon so I bought it. Will that work with adafruit's libraries? I can't find a datasheet for it.

[Breadbocks]

Those are WS2812s according to the product name, so there's no reason that Adafruit's NeoPixel libraries wouldn't work with them.

[dubiousSwain]

Originally Posted by Breadbocks

Those are WS2812s according to the product name, so there's no reason that Adafruit's NeoPixel libraries wouldn't work with them.

There are 5 wires, is one of them the latch? Should I use the old tutorial? I can't find a pinout for it.

[Breadbocks]

In the picture there are only 3 solder pads on the strip, which means there should only be 3 wires coming out. Can you post a picture of where the leads meet the strip so I can see what on earth the other 2 wires go to? There *should* only be a wire to +5V, DIn (NOT DO), and GND.

[dubiousSwain]

Originally Posted by Breadbocks

In the picture there are only 3 solder pads on the strip, which means there should only be 3 wires coming out. Can you post a picture of where the leads meet the strip so I can see what on earth the other 2 wires go to? There *should* only be a wire to +5V, DIn (NOT DO), and GND.

I took off the heatshrink, 2 wires were wired to the power and ground pads.

I got it working with Adafruit's libraries, thanks for all your help.