NodeMCU DS18B20 station

config.lua

-- Use this to configure NodeMCU to connect your AP

local STATION_CONFIG = {}
STATION_CONFIG.ssid = "my ssid"
STATION_CONFIG.pwd = "my password"
STATION_CONFIG.auto = true
STATION_CONFIG.save = true

wifi.setmode(wifi.STATION)
wifi.sta.config(STATION_CONFIG)
wifi.sta.connect()

init.lua

-- Requires ds18b20 and ow modules

local OW_BUS_PIN = 3
local RES = 10
local PORT = 80
local HEADER = "HTTP/1.1 200 OK\nContent-Type: text/plain; charset=utf-8\n\n"
local ERROR_400 = "HTTP/1.1 400 Bad Request\n\n"
local ERROR_404 = "HTTP/1.1 404 Not Found\n\n"

local function addr2string(addr)
    return string.format("%02X:%02X:%02X:%02X:%02X:%02X:%02X:%02X",
        string.byte(addr, 1), string.byte(addr, 2), string.byte(addr, 3),
        string.byte(addr, 4), string.byte(addr, 5), string.byte(addr, 6),
        string.byte(addr, 7), string.byte(addr, 8))
end

local function find(f_addr)
    ow.reset_search(OW_BUS_PIN);
    ow.target_search(OW_BUS_PIN, tonumber(string.sub(f_addr, 1, 2)));
    local s_addr = nil
    repeat
        s_addr = ow.search(OW_BUS_PIN)
        if s_addr ~= nil then
            s_addr = addr2string(s_addr)
        end
    until s_addr == nil or s_addr == f_addr
    return s_addr ~= nil and s_addr == f_addr
end

local function setup()
    local addrs = {}
    local count = 0;
    ds18b20.setup(OW_BUS_PIN)
    ow.reset_search(OW_BUS_PIN);
    ow.target_search(OW_BUS_PIN, 0x28);
    local addr = ow.search(OW_BUS_PIN);
    while addr ~= nil do
        count = count + 1
        addrs[count] = addr2string(addr)
        addr = ow.search(OW_BUS_PIN)
    end
    ds18b20.setting(addrs, RES)
end

local function close(conn) conn:close() end

local function receiver(sck, data)
    local path = string.match(data, "GET ([^ ]+) HTTP.*")
    if path == nil then
        sck:send(ERROR_400, close)
    else if path == "/" then
        ow.reset_search(OW_BUS_PIN)
        sck:send(HEADER, function(conn) 
            local addr = ow.search(OW_BUS_PIN)
            if addr ~= nil then
                conn:send(addr2string(addr) .. "\n")
            else
                conn:close()
            end
        end)
    else
        local addr = string.match(path, "/(%x+:%x+:%x+:%x+:%x+:%x+:%x+:%x+)")
        if addr == nil then
            sck:send(ERROR_404, close)
        else
            if not find(addr) then
                sck:send(ERROR_404, close)
            else
                ds18b20.read(function(index, rom, res, temp, temp_dec, par)
                    sck:send(HEADER .. string.format("%f°C\n", temp), close)
                end, {addr})
            end
        end
    end end
end

setup()

local srv = net.createServer(net.TCP)
srv:listen(PORT, function(conn) conn:on("receive", receiver) end)