Lua and Neopixels

I had to learn several programming languages in a relative short time. I learned to program in Python, C++, Mit App inventor, and I learned some HTML. And now I had to learn LUA.

LUA is one of the programming languages used in the ESP8266 boards. It is the standard language for the NodeMCU boards.

So as I had to learn so many languages in a short time I struggled a bit with it.

The Problem:

I wanted to control a bunch of Neopixels (WS2812 leds) with my ESP-8266-01. Luckily enough there is a driver incorporated in the Lua language. The drivers description is as follows:

ws2812.writergb()

Description 
Send the RGB Data in 8bits to WS2812

Syntax

ws2812.writergb(pin, string.char(R1,G1,B1(,R2,G2,B2...)) )

Parameters

pin = Supported all the PINs(0,1,2...)
R1 = The first WS2812 though the line's Red Channel's Parameters（0-255）
G1 = The first WS2812 though the line's Green Channel's Parameters（0-255）
B1 = The first WS2812 though the line's Blue Channel's Parameters（0-255）
... You can connect a lot of WS2812...
R2,G2,B2 is the next WS2812's Red, Green and Blue Channel's Parameters 
  
Looks easy enough. So what I did is I send a snippet to the ESP8266-01 looking like this:

ws2812.writergb(3, string.char(120, 25, 80):rep(7))

And all 7 of my Neopixels displayed a nice white/purplisch color.
Note that the first I/O port of the ESP8266-01 being I/O 0 is attached to pin 3......

But that is not what I wanted. I wanted to adress all Neopixels seperately. I wanted each WS2812 to have a different colour.

That made things a bit more complicated.
The syntax for adressing all 7 pixels is:

 ws2812.writergb(3,R1,G1,B1,R2,G2,B2,R3,G3,B3,R4,G4,B4,R5,G5,B5,R6,G6,B6,R7,G7,B7)

This looks easy and that is right. However programming it is a bit more complicated.

Solution.

Here is my solution. 

I start with defining the colors.
Note that the higher the values, the brighter the Neopixels will be. You can make as many different color combinations as you want.

I made an Array which is as large as the number of Neopixels I had attached. In this case 7 pieces. And then I filled the array with the RGB values: first 3 with blue (b), the next one red (r) and the last 3 with green (g).

And the actual line to set the pixels is:

ws2812.writergb(3,n[1]..n[2]..n[3]..n[4]..n[5]..n[6]..n[7])

So this makes it very easy to adress the individual Neopixels which makes it easy to control them in various projects.

Till next time.
Have fun

Luc Volders