ajfisher/node-pixel

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

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!

Eric Brearley

@ebrearley

First step is done, I have flashed my arduino with the node-pixel firmata and written a simple test app in node. The RGBW SK6812 strip lights up and it's showing a sequence of what looks like W, RGB and WR. the leading pixel is green.

(oh i'm showing full white, 255,255,255)

I can address each pixel individually, win!

Eric Brearley

@ebrearley

I'm assuming that this will be resolved with the addition of the RGBW colourspace

I also want to be able to address 300 pixels on a single data line, so adding that to the list too

ajfisher

@ajfisher

Apologies for tardiness on reply - I did see this yesterday but we're mid cut-over week on site launch! Love the gif and reflection in the mirror.

So I don't have any of those LEDs to play with but if you change the byte order in nodepixel config did that fix it for you?

ajfisher

@ajfisher

nvm you probably can't fix that until you pad out the white channel. You could potentially hack that in the firmware to simply pad that byte with a zero for the moment.

In theory if you bump this to 4 it should pad out the last byte as well.

https://github.com/ajfisher/node-pixel/blob/master/firmware/src/libs/ws2812/ws2812.cpp#L15

Eric Brearley

@ebrearley

No probs! I'm enjoying it! I'll try to implement it nicely tonight if I have time (instead of hacking it in) and send you a pull request. But i might resort to the hack on account of not really understanding a great deal of what I'm doing.

I was thinking of comparing the latest adafruit library and porting across node-pixel again to update it. I wouldn't mind the setBrightness() method. Although I'm sure it's not included already for a good reason.

Eric Brearley

@ebrearley

Okay I was a touch ambitious, but making progress non the less. I need to find out how to do a few basic things, like get a log out from the formata to see the args as they flow through. What I do have is blue and green led's lighting up, but nothing else exciting. I'll push what I've done so you can have a looksie.

Eric Brearley

@ebrearley

Okay here's my start ajfisher/node-pixel#101

Jordana

@JordanaHarrison

Hello, does anyone know of a way to animate through pixel brightness with this library? I don't see any built-in thing in the docs. I'd like to do a pulsing animation, but want to see if there's a way beyond just decrementing the RGB values. Thanks!

Luis Montes

@monteslu

@ajfisher the Melbourne event isnt on the nodebotsday repo

possumus

@possumus

@ajfisher Can I use an Adafruit Trinket as the I2C backpack?

ajfisher

@ajfisher

@possumus sort of - you can give it a go but debugging is hard on a trinket. I actually started with the trinket as my backpack but lack of serial port for debugging just made it really, really hard.

Also because they aren't really designed for any serial interfaces they use this weird thing called USI which means your I2C comms can get a bit iffy. My suggestion is that if you have time just order a cheap Nano or Pro Mini from ebay for a few $$ and you'll get something very useful in a tiny form factor.

possumus

@possumus

@ajfisher Thanks a lot for getting back to me! I had a Trinket lying around and thought it would be a quick hack. I just ordered Nano! Will keep you posted and thanks again for the great library :)

possumus

@possumus

@ajfisher Hi again! So I got my hands on a nano and followed the "I2C Backpack Installation" by installing the Arduino IDE, then uploading the backpack.ino (found in nedo-pixel/firmware/build/backpack). Then I ran the johnnyfive-i2c.js from the examples folder. Here is what I get:
1502418425559 Available /dev/ttyUSB0
1502418425611 Connected /dev/ttyUSB0
1502418435621 Device or Firmware Error A timeout occurred while connecting to the Board.

Please check that you've properly flashed the board with the correct firmware.
See: https://github.com/rwaldron/johnny-five/wiki/Getting-Started#trouble-shooting

If connecting to a Leonardo or Leonardo clone, press the 'Reset' button on the board, wait approximately 11 seconds for complete reset, then run your program again.
events.js:165
throw err;
^

Error: Uncaught, unspecified "error" event. ([object Object])
at Board.emit (events.js:163:17)
at Board.log (/home/pi/Workspace/neoPixelTest/node-pixel/node_modules/johnny-five/lib/board.js:635:8)
at Board.(anonymous function) [as error] (/home/pi/Workspace/neoPixelTest/node-pixel/node_modules/johnny-five/lib/board.js:646:14)
at Board.<anonymous> (/home/pi/Workspace/neoPixelTest/node-pixel/node_modules/johnny-five/lib/board.js:390:14)
at ontimeout (timers.js:386:14)
at tryOnTimeout (timers.js:250:5)
at Timer.listOnTimeout (timers.js:214:5)

I found a similar post in the issue list which dealing with the Frimata on an Uno and not the backpack. Could you please help us?

Rajesh

@Rajesh_YRe_twitter

@ajfisher / all I am using the rainbow-dynamic.js example. I have exported the symbols and am invoking these functions from another js instance. This works fine. I can run the rainbow program but when I invoke a strip.off() or using strip.pixel(x).color it doesn't work till the previous color pattern is completed.

is there any way to immediately stop the pattern

@possumus I too have the same problem. This means that the board is not able communicate with pixel. Try to load a blank loop from the Arduino ide. After that retry the interchange step. It is a bit of struggle.

ajfisher

@ajfisher

@possumus So don't forget a backpack is to connect to another device over I2C. See this doc / diagram for some additional info: https://github.com/ajfisher/node-pixel/blob/master/docs/johnnyfive-i2c.md

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