What is Lua?

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Lua is a powerful, efficient, lightweight, embeddable scripting language. It supports procedural programming, object-oriented programming, functional programming, data-driven programming, and data description.

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Lua combines simple procedural syntax with powerful data description constructs based on associative arrays and extensible semantics. Lua is dynamically typed, runs by interpreting bytecode with a register-based virtual machine, and has automatic memory management with incremental garbage collection, making it ideal for configuration, scripting, and rapid prototyping.

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Lua is free

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Lua is free open-source software, distributed under a very liberal license (the well-known MIT license). It may be used for any purpose, including commercial purposes, at absolutely no cost. Just download it and use it.

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METAS and Lua

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You can impot Lua via lualoader to METAS NodeOne.
Make sure is connect with USB port.

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Lua Tutorial:

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1. Connect to the wireless network
print(wifi.sta.getip())
–nil
wifi.setmode(wifi.STATION)
wifi.sta.config(“SSID”,”password”)
wifi.sta.connect()
tmr.alarm(1, 1000, 1, function()
if wifi.sta.getip() == nil then
print(“Connecting…”)
else
tmr.stop(1)
print(“Connected, IP is “..wifi.sta.getip())
end
end)

2. HTTP Server
— a simple http server
srv = net.createServer(net.TCP)
srv:listen(80, function(conn)
conn:on(“receive”, function(sck, payload)
print(payload)
sck:send(“HTTP/1.0 200 OK\r\nContent-Type: text/html\r\n\r\n<h1> Hello, NodeMCU.</h1>”)
end)
conn:on(“sent”, function(sck) sck:close() end)
end)

3. DISPLAY
function prepare()
disp = u8g.ssd1306_128x64_i2c(0x3c)
disp:setFont(u8g.font_chikita)
disp:setFontRefHeightExtendedText()
disp:setDefaultForegroundColor()
disp:setFontPosTop()
disp:setScale2x2()
end

function init_display()
disp:firstPage()
repeat
disp:drawStr(9,0,”METAS IOT”)
disp:drawStr(8,20,”Please Wait”)
until disp:nextPage() == false
end

i2c.setup(0,7,6,i2c.SLOW)
prepare()
init_display()

4. Control
–Control D1–
gpio.mode(1,gpio.OUTPUT)
gpio.write(1,gpio.HIGH)

–Control D2 —
gpio.mode(1,gpio.OUTPUT)
gpio.write(1,gpio.LOW)

–Read A0–
gpio.mode(8,gpio.OUTPUT)
gpio.write(8,gpio.HIGH)
A0 = adc.read(0)

–Read A1–
gpio.mode(8,gpio.OUTPUT)
gpio.write(8,gpio.LOW)
A1 = adc.read(0)

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How to write and copy your own program?

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Currently the firmware and tutorial of METAS company are mainly achieved by virtual machine with NodeMCU LUA language. For more details about NodeMCU virtual machine, please visit www.nodemcu.com/index_cn.html. In the next software update, METAS company will provide more examples of Mirco Pyton virtual machine.