Using a pebble watch to control NeoPixel (WS2812 ) LEDs via an ESP8266 controller

_Pebble controlled NeoPixels using ESP8266.md

This is the general instructions for how to get a pebble watch to talk to an ESP8266 and turn NeoPixels different colours.

Video: https://www.youtube.com/watch?v=BeIQ47WBVXs

Prereqs

• Pebble watch
• ESP8266 ESP-01
• NeoPixel strip (or ring or matrix or single pixel)

Software needed

• ESPTool
• ESPlora
• Pebble SDK and command line tools

Acknowledgements

Thanks to Andy Gelme for his excellent workshop on the ESP8266 and getting me up to speed on the Lua side.

Directions

• Using ESPTool, flash the ESP8266 with NodeMCU development branch (bins are in this gist) so it has WS8212 support.
• Using ESPlora, change config.lua to have SSID / PASSWORD of your network in them - upload all lua files to the ESP8266
• Wire up the WS2812 strip so data line is connected to GPIO 2 (change this in server.lua if you use a different pin).
• Reset the ESP8266 and note it's IP address in ESPlora when it comes up. You should now be able to hit the web server using

curl --data "red=255&green=0&blue=255" http://<IP address>

• Using CloudPebble, copy app.js contents into the app.js file (make a watch app project and use Pebble JS)
• Change the HOST IP address to that of your ESP8266
• Compile and then download the PBW file
• Use the developer configuration (as documented by Pebble SDK setup) to run:

pebble install watch_led.pbw

That's it - you should be able to hit it as expected.

app.js

/**

  Pebble - ESP8266 - NeoPixel controller
  
  Author: Andrew Fisher
  Licence: MIT

**/
var UI = require('ui');
var ajax = require('ajax');

var HOST = '<<IP>>';


// Connect to the ESP8266 and post the data
function colour_request(r, g, b) {
  //console.log("Making request");
  //console.log("r:" + r + " g: " + g);
  
  var req = {
    url: HOST,
    method: 'post',
    data: {red:r, green:g, blue:b}
  };
  
  //console.log(JSON.stringify(req));
  
  ajax(req,
    function(data, status, request) {
      console.log(data);
    },
    function(data, status, request) {
      console.log('The ajax request failed: ' + data + status + JSON.stringify(request));
    }
  );

}

// Make a list of the colours to select
var colours = [
  { title: "OFF", r: 0, g: 0, b: 0, },
  { title: "RED", r: 255, g: 0, b: 0, },
  { title: "GREEN", r: 0, g: 255, b: 0, },
  { title: "BLUE", r: 0, g: 0, b: 255, },
  { title: "YELLOW", r: 255, g: 255, b: 0,  },
  { title: "MAGENTA", r: 255, g: 0, b: 255, },
  { title: "CYAN", r: 0, g: 255, b: 255, },
  { title: "WHITE", r: 255, g: 255, b: 255, },
];

// Create the Menu
var menu = new UI.Menu({
  sections: [{
    title: 'Choose LED colour',
    items: colours
  }]
});

// Send command when menu item is selected
menu.on('select', function(e) {
  colour_request(e.item.r, e.item.g, e.item.b);
});
      
menu.show();

application.lua

local module = {}

function module.start()
  print("application start")
  print("IP address: " .. wifi.sta.getip())

  dofile("server.lua")

end

return module

config.lua

local module = {}

module.SSID = {}
module.SSID["SSID"] = "PASSWORD"



return module

init.lua

app    = require("application")
config = require("config")

require("setup").start()

nodemcu_dev_0x00000.bin

nodemcu_dev_0x10000.bin

server.lua

local PORT = 80
local LED_PIN = 4 -- GPIO 2
local BRIGHTNESS = 0.2 -- NeoPixels are BRIGHT.
local NO_PIXELS = 17

if server then
     print("Closing existing server")
     server:close()
end

print("Starting server on: " .. wifi.sta.getip() .. ":" .. PORT)

server = net.createServer(net.TCP)
server:listen(PORT, function(conn)

     conn:on("receive", function(client, payload)
          -- print(payload)
          local head = ""
          local body = ""
          local colours = {}
          colours["red"] = 0
          colours["green"] = 0
          colours["blue"] = 0
     
          if (string.sub(payload, 1, 4) == "POST") then
               head = head .. "HTTP/1.1 200 OK\r\n"
               head = head .. "Content-Type: application/json\r\n"

               -- now we find the RGB components. Going to do this simply
               -- by ripping them out with a find statement
               for c, v in pairs(colours) do
                    local match = c .. "=(%d*)"
                    _, _, colours[c] = string.find(payload, match)
                    -- put in a catch here incase it goes nil
               end

               set_led_colour(colours, NO_PIXELS)

               -- send the JSON back to confirm
               body = body .. "{\"r\":" .. colours["red"] .. ", "
               body = body .. "\"g\":" .. colours["green"] .. ", "
               body = body .. "\"b\":" .. colours["blue"] .. "}"
          else
               head = head .. "HTTP/1.1 500 Server Error\r\n"
               body = body .. "Please ensure you use a POST method"
          end

          body = body .. "\r\n" -- just tidy up the end of the file
          head = head .. "Content-Length: " .. string.len(body) .. "\r\n\r\n"
          
          --print(head .. body)
          client:send(head .. body)
     
     end)
     
     conn:on("sent", function(client) 
          client:close() 
     end)

end)


function create_colour(red, green, blue)
     -- takes the colours and makes single value for writing to the LEDs
     local colour = string.char(green * BRIGHTNESS, red * BRIGHTNESS, blue * BRIGHTNESS)
     return colour
end

function set_led_colour(colours, pixels)
     -- takes the colour values and writes that to the number of pixels
     -- assmues a table colours{"red":val, "green":val, "blue":val}
     ws2812.write(LED_PIN, create_colour(colours["red"], colours["green"], colours["blue"]):rep(pixels))
end

setup.lua

local module = {}

local function wifi_wait_ip()
  if wifi.sta.getip() then 
    tmr.stop(1)
--  print("wifi ready: " .. wifi.sta.getip())
    app.start()
  end 
end

local function wifi_start(aps)
  for key,value in pairs(aps) do
--    print("wifi AP: " .. key .. ": " .. value)
    if config.SSID and config.SSID[key] then
      wifi.sta.config(key, config.SSID[key])
      wifi.sta.connect()
      config.SSID = nil  -- more secure and save memory
      tmr.alarm(1, 2500, 1, wifi_wait_ip)
    end
  end
end

function module.start()
  wifi.setmode(wifi.STATION);
  wifi.sta.getap(wifi_start)
end

return module

@ajfisher: This is really cool, thank you! Could you also provide a simple schematic with the wiring?