ajfisher/node-pixel

Library for using addressable LEDs (such as NeoPixels/WS2812) with Firmata and JohnnyFive

Ben Shapiro

@bennytheshap

ank yu

ajfisher

@ajfisher

No worries at all - and here's code example for beaglebone

var five = require("johnny-five");
var pixel = require("node-pixel.js");
var io = require("beaglebone-io");

var opts = {
  io: new BeagleBone();
};

var board = new five.Board(opts);

// etc...

Ben Shapiro

@bennytheshap

THANKS!

ajfisher

@ajfisher

No probs at all. Keep me posted on results.

KronKraken

@KronKraken_twitter

Soo would that work?

KronKraken

@KronKraken_twitter

Also, which arduino needs to be connected to the PC? The Uno or the nano? Or even both

ajfisher

@ajfisher

@KronKraken_twitter Yep that will work.

In terms of what's connected to what:

Uno connect to the PC - Uno runs standardfirmata
Nano just connected between Uno and LEDs and runs NodePixel Backpack

KronKraken

@KronKraken_twitter

Okay. I ordered the Nano, when it arrives I'll try it and make sure to share the results.

One last question before I can stop bothering you :X

Would this work?

ajfisher

@ajfisher

@KronKraken_twitter Cool. Yep that will work.

Only thing to just keep an eye on is if you're getting weird drop outs on the nano it might be because the Uno isn't giving you enough supply. I haven't seen this frequently in this set up - it's more the specifics of the particular nano and uno that are in combination together.

If that happens then I'd just run a 5V line back from the end of the strip to the 5V pin on the nano and it will stabilise the supply

KronKraken

@KronKraken_twitter

Okay then! I'll just have to wait for the nano to arrive, and I shall share the results! Thank you very much for all the help!

KronKraken

@KronKraken_twitter

Oh hey! So it's been 3 days, and the nano has arrived and it works!

Finally!

ajfisher

@ajfisher

Awesome!

KronKraken

@KronKraken_twitter

Thankyou for all the help, without you I wouldn't have been able to do this.

Ben Shapiro

@bennytheshap

@ajfisher thanks again for your help! Lila got her sculpture working great.

KronKraken

@KronKraken_twitter

Hey any plans for the Ranging Feature to get implemented?

I'd really benefit from it

KronKraken

@KronKraken_twitter

or is there a documentation to the node-pixel protocol? I could work on it and make a pull request

ajfisher

@ajfisher

@bennytheshap Awesome!

@KronKraken_twitter so I started working through how it would all work but then got stuck into building tests and working on some performance things first before I started in on that.

There's a proposal for the way the protocol should work here:

https://github.com/ajfisher/node-pixel/blob/master/firmware/src/libs/protocol.md#shift-pixels---proposal

Actually sorry - still 90% asleep and no coffee to my day yet.

That's SHIFT

ajfisher @ajfisher facepalm

ajfisher

@ajfisher

Okay so the way the ranging stuff should work is it basically you send a top and bottom ID and then a colour that you want to set them to. Protocol should probably looks like this:

0   START_SYSEX         0xF0
1   PIXEL_COMMAND       0x51
2   PIXEL_SET_RANGE     0x06
3   max 14 bit index of FROM pixel in strip LSB
4   max 14 bit index of FROM pixel in strip MSB
5   max 14 bit index of TO pixel in strip LSB
6   max 14 bit index of TO pixel in strip MSB
7   24 bit packed RGB FROM color value LSB
8   24 bit packed RGB FROM color value lower middle bits
9   24 bit packed RGB FROM color value upper middle bits
10   24 bit packed RGB FROM color value MSB
11   24 bit packed RGB TO color value LSB
12   24 bit packed RGB TO color value lower middle bits
13   24 bit packed RGB TO color value upper middle bits
14   24 bit packed RGB TO color value MSB
15   END_SYSEX           0xF7

Bytest 11-14 would be optional and I'd say don't worry about these just yet.

ajfisher

@ajfisher

Idea here is you send a ranging command and then tell it the index of the pixels you want to set from and to - I'd say this is inclusive so if it was 12 and 15 then pixels 12, 13, 14, 15 would all be affected.

KronKraken

@KronKraken_twitter

-snip- sorry i'm staying up later than I should so my mind is also a bit slow xd

I'll try that tomorrow, and I shall share the results

ajfisher

@ajfisher

No worries at all.

So by way of some additional information.

What you'd do is the following:

Add a new handler in here for the new set range command - https://github.com/ajfisher/node-pixel/blob/master/firmware/src/libs/ws2812/ws2812.cpp#L162
Grab your colours and pixel indexes out using eg this: https://github.com/ajfisher/node-pixel/blob/master/firmware/src/libs/ws2812/ws2812.cpp#L202-L204
Then set your pixels to appropriate colour: https://github.com/ajfisher/node-pixel/blob/master/firmware/src/libs/ws2812/ws2812.cpp#L210

Depending on how gnarly you want to get there is probably an optimisation in here which is to build a byte array of memory that is the range you're after and then simply memcpy it over the range in the *pixels array. But deal with that later.

ajfisher

@ajfisher

Then on the Node side you're pretty much doing the same thing with a new method eg: strip.range(m, n).colour(rrggbb)

If you note the above you can see I've added a range intermediary there because I think API wise there's a bunch of things we could do on a range for example shifting and cycling across a range of pixels as you sort of do on a Strip already

but don't worry too much about that at this point, it's just pre-planning on the design

KronKraken

@KronKraken_twitter

So I got something working

But I've been having some difficulties implementing it in a way where the rest of the API can relate to

like to use .range().shift()

Also didn't get why you want to add a second value to the colors

So for now I think it'd be better if I don't submit a pull request

ajfisher

@ajfisher

Have you got it in a branch and I can have a look?

The rationale for the second color value was so you can interpolate between the start and end pixel across the values - eg make a rainbow in one line of code or just gradient blend between points etc.

But start with simple single colour applied to all the pixels in the range and that will be awesome - much of that stuff was so it's documented so we can go back to it as well.

Eric Brearley

@ebrearley

I just spent the weekend installing LED bling into my kitchen. Maybe a little bit to the dismay of fiancé - but hey she knew that this was part of the deal when she met me :p! ANYWAY!

The setup is a strip of approximately 300 SK6812 RGBW LEDS, controlled by an Arduino MEGA (so i wouldn’t have to worry about memory constraints).

It already looks pretty good (native Adafruit RGBW test sketch)!
http://imgur.com/Ezx08bs

I’m a web dev by day, which means i have grand plans for controlling the setup remotely. Web control, native app, wifi switches - the works. And it turns out that there’s a bit of groundwork to do.

node-pixel needs me (or someone) to:

Add support for the SK6812 protocol (ajfisher/node-pixel#73)
Add RGBW to the supported colourspaces (ajfisher/node-pixel#64)

And while i’m at it, add back the interchange configuration option (ajfisher/node-pixel#93) - I have a MEGA, what even is small memory capacity? ;)

I’m a newbie (one day into it now) to the world of microcontrollers, interchange, backpacks, loading firmware. Send me your un-newbie-ifying reading recommendations please! In saying that, I won’t be doing anything quickly, and I will be asking for help.

So, hI! And be speaking to you guys soon!

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