WS 28xx Led Strip Support

[graysonarts]

I'm working on adding support for ws2812 and ws2801 led strip to firmata. I have a working prototype that seems to work well for the ws2812. I branched off of configurable_dev, but I would like to see if how I'm approaching it is in line with how you want things designed for firmata. I tried to base my code off of Encoder and Stepper.

The code is checked in here: https://github.com/RussTheAerialist/arduino/tree/neopixel_strip
And you can see my sample .ino running faster than the camera framerate (only 1 led is on at a time): http://instagram.com/p/wRWdd3tpj1/

[soundanalogous]

Can you submit a pull request? It will be easier to review your code. I may not have time to review it for a few days but perhaps @ntruchsess can take a look?

Also, as I mentioned for your NeoPixel protocol proposal we (the firmata maintainers) have been avoiding adding device-specific (a specific neopixel vs a generic led strip protocol for example) classes to utility. Instead we have been requesting that device-specific implementation be added as examples (here is one such example). This is partly because there are only so many command bytes available (those remaining in the range of 0x10 - 0x7F).

However as we see more device-specific proposals it may make sense to try to include them in the protocol somehow, but it will require an additional byte in order to further classify the device. Here are a couple of options

// use a command byte to indicate this is a specific device
// this is simple and limited to 127 devices
0  START_SYSEX                    (0xF0)
1. DEVICE                                (0x10)
2  NEOPIXEL_DATA                (some value between 0x00 - 0xF7)
... 
N  END_SYSEX                 (0xF7)

OR

// use a range of command bytes to classify type of devices
// this approach would support the widest range but classification could get messy
0  START_SYSEX                    (0xF0)
1. LED_STRIP                           (0x10) // where some range is dedicated to device classifications
2  NEOPIXEL_DATA                (some value between 0x00 - 0xF7) // a specific device in this classification
... 
N  END_SYSEX                 (0xF7)

@ntruchsess, I'd like to get your thoughts here as well

[graysonarts]

Sure, I'm going to work up a more generic implementation of the ledstrip protocol, and then setup a way to specify which type of led strip you want to use when compiling the firmata. Once I get that written up (probably won't be for a day or two), I'll submit a pull request.

[ajfisher]

@RussTheAerialist So I'm doing a bunch of work on this at the moment based on the code I did a few months back. I've got several solid days to work on this right now so if you want I can smash this out.

[graysonarts]

@ajfisher I have most of an implementation done for the ws2812 at https://github.com/RussTheAerialist/arduino/tree/neopixel_strip . If you wanted to add the ws2801 (which I think is what you were working on here ), that would be awesome!

[ajfisher]

I'm working on the 2812 as well but can probably do some hacking on 2801 too as I have some access to them.

Where in your branch did you pull it in?

I'm specifically rewriting my code here: https://github.com/ajfisher/rgbled to remove the requirement for the Adafruit library and make it more maintainable.

[graysonarts]

Oh awesome, I branched off of configurable_dev from https://github.com/firmata/arduino/tree/configurable_dev

[soundanalogous]

See #132 for an update on how we're thinking to include Firmata features that wrap 3rd party libraries.

[graysonarts]

I'm going to withdraw this proposal for now. This was original written to add support into Johnny-five, but Rick and a few others came up with a better solution (I2C interface for led strips), so I think this is no longer needed