diff --git a/README b/README
index 6ababf4..38848ce 100644
--- a/README
+++ b/README
@@ -7,8 +7,12 @@ the IO expander and the PN532 are written in Lua.
 
 Files:
     hslockmk2/                       - this directory
-             /code.lua               - main Lua source code
-             /lua-libs/              - necessary Lua libraries
+             /main.lua               - main Lua script
+             /i2c.lua                - I2C functions
+             /nfc.lua                - NFC/PN532 functions
+             /auth.lua               - auth API functions
+
+             /lua-libs/              - other Lua libraries
                       /mips-bin/     - C libraries compiled for MIPS/OpenWRT
                       luai2c.tar.gz  - C i2c library
                       luasha2.tar.gz - C sha2 library
diff --git a/auth.lua b/auth.lua
new file mode 100644
index 0000000..7e6fd3d
--- /dev/null
+++ b/auth.lua
@@ -0,0 +1,53 @@
+require('socket')
+local sha2 = require('libsha2')
+local https = require('ssl.https')
+
+q3k.Auth = {}
+
+-- the PIN is a table like { 1, 2, 3, 4 }
+-- the NFC ID is a table like { 0xde, 0xad, 0xbe, 0xef }
+local CalculateHash = function(PIN, NFCID)
+    local PINString = string.format("%i%i%i%i", PIN[1], PIN[2], PIN[3], PIN[4])
+    local PINNumber = tonumber(PINString)
+    local IDString = string.format("%02x%02x%02x%02x", NFCID[4], NFCID[3], NFCID[2], NFCID[1])
+    local Source = string.format("%08x:%s", PINNumber, IDString)
+    return sha2.sha256hex(Source)
+end
+
+local GetUserFromHash = function(Hash)
+    local Body, Code, Headers, Status = https.request('https://auth.hackerspace.pl/mifare', 'hash=' .. Hash)
+    if Code ~= 200 then
+        return nil
+    end
+    if #Body > 100 then
+        -- probably an error code
+        return nil
+    end
+    return Body
+end
+
+
+----------------
+-- Public API --
+----------------
+
+q3k.Auth.CardStatus = {
+    -- No such card in the system - disallow
+    NO_MATCH=1,
+    -- Card okay - allow
+    OKAY=2,
+    -- Card okay, but member should pay soon - allow, but notify
+    PAYMENT_DUE=3,
+    -- Card okay, but member is way behing in payments - disallow
+    PAYMENT_REQUIRED=4
+}
+
+q3k.Auth.GetCardStatus = function(PIN, NFCID)
+    local Hash = CalculateHash(PIN, NFCID)
+    local User = GetUserFromHash(Hash)
+
+    if User == nil then
+        return { Status = q3k.Auth.CardStatus.NO_MATCH }
+    end
+    return { Status = q3k.Auth.CardStatus.OKAY, User = User }
+end
diff --git a/code.lua b/code.lua
deleted file mode 100644
index 818e3c1..0000000
--- a/code.lua
+++ /dev/null
@@ -1,234 +0,0 @@
--- The MIT License (MIT)
--- 
--- Copyright (c) 2013 Sergiusz 'q3k' Bazański <q3k@q3k.org>
---
--- Permission is hereby granted, free of charge, to any person obtaining a copy
--- of this software and associated documentation files (the "Software"), to deal
--- in the Software without restriction, including without limitation the rights
--- to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
--- copies of the Software, and to permit persons to whom the Software is
--- furnished to do so, subject to the following conditions:
---
--- The above copyright notice and this permission notice shall be included in
--- all copies or substantial portions of the Software.
---
--- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
--- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
--- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
--- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
--- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
--- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
--- THE SOFTWARE.
-
--- This is the HSWAW lock mk2. source code. WIP. refucktor badly needed.
-
-local i2c = require("libluai2c")
-require('bit')
-require('socket')
-require('posix')
-local sha2 = require('libsha2')
-local https = require('ssl.https')
-
-q3k = {}
-q3k.Config = {}
-
-q3k.Config.I2CBus = 0
-
-q3k.Config.I2CGPIO = 0x40
-q3k.Config.I2CNFC = 0x24
-
-q3k.I2CWrite = function(Address, ...)
-    local Data = {...}
-    local Bytes = string.format("%02x ", Address)
-    for _, Byte in pairs(Data) do
-        Bytes = Bytes .. string.format("%02x ", Byte)
-    end
-    local DataString = string.char(unpack(Data))
-    return i2c.write(q3k.Config.I2CBus, Address, DataString)
-end
-
-q3k.I2CRead = function(Address, BytesOut, ...)
-    local Data = {...}
-    local DataString = string.char(unpack(Data))
-    local Status, Data = i2c.read(q3k.Config.I2CBus, Address, BytesOut, DataString)
-    local Return = {}
-
-    if Status == 0 then
-        Data:gsub(".", function(c)
-            Return[#Return+1] = string.byte(c)
-        end)
-        return Return
-    end
-end
-
--- sigh. luaposix on openwrt doesn't have nanosleep()
-q3k.Sleep = function(Seconds)
-    socket.select(nil, nil, Seconds)
-end
-
--- GPIO Functions
-q3k.SetupGPIO = function()
-    -- Set up pins 28, 29, 30, 31 as output
-    q3k.I2CWrite(q3k.Config.I2CGPIO, 0x0F, 0x55)
-    q3k.DoorClose()
-    -- Set up pins 12, 13, 14, 15 as input without pullups
-    q3k.I2CWrite(q3k.Config.I2CGPIO, 0x0B, 0xAA)
-
-    -- Turn on GPIO Multiplexer
-    q3k.I2CWrite(q3k.Config.I2CGPIO, 0x04, 0x01)
-end
-
-q3k.DoorOpen = function()
-     -- Turn on pin 31 (door)
-        q3k.I2CWrite(q3k.Config.I2CGPIO, 0x3F, 0x01)
-end
-
-q3k.DoorClose = function()
-     -- Turn off pin 31 (door)
-        q3k.I2CWrite(q3k.Config.I2CGPIO, 0x3F, 0x00)
-end
-
--- NFC (PN532) functions
-local PN532_PREAMBLE = 0x00
-local PN532_STARTCODE1 = 0x00
-local PN532_STARTCODE2 = 0xFF
-local PN532_POSTAMBLE = 0x00
-
-local PN532_HOSTTOPN532 = 0xD4
-local PN532_PN532TOHOST = 0xD5
-
-q3k.NFCIRQRead = function()
-    local Data = q3k.I2CRead(q3k.Config.I2CGPIO, 1, 0x2C)
-    if Data then
-        return Data[1]
-    else
-        return 1
-    end
-end
-
-q3k.NFCWaitForIRQ = function(Timeout)
-    local Timeout = Timeout or 5
-    local WaitStart = os.time()
-    while os.time() < WaitStart + Timeout do
-        local IRQStatus = q3k.NFCIRQRead()
-          if IRQStatus == 0 then
-            break
-        end
-        q3k.Sleep(0.2)
-    end
-    local IRQStatus = q3k.NFCIRQRead()
-        if IRQStatus ~= 0 then
-                return false
-        end
-    return true
-end
-
-q3k.NFCWriteCommand = function(...)
-    local Command = {...}
-    local Checksum = PN532_PREAMBLE + PN532_STARTCODE1 + PN532_STARTCODE2
-    local WireCommand = { PN532_PREAMBLE, PN532_STARTCODE1, PN532_STARTCODE2 }
-
-    WireCommand[#WireCommand+1] = (#Command + 1)
-    WireCommand[#WireCommand+1] = bit.band(bit.bnot(#Command +1) + 1, 0xFF)
-
-    Checksum = Checksum + PN532_HOSTTOPN532
-    WireCommand[#WireCommand+1] = PN532_HOSTTOPN532
-
-    for _, Byte in pairs(Command) do
-        Checksum = Checksum + Byte
-        WireCommand[#WireCommand+1] = Byte
-    end
-
-    WireCommand[#WireCommand+1] = bit.band(bit.bnot(Checksum), 0xFF)
-    WireCommand[#WireCommand+1] = PN532_POSTAMBLE
-
-    q3k.I2CWrite(q3k.Config.I2CNFC, unpack(WireCommand))
-end
-
-q3k.NFCSendAndAck = function(...)
-    q3k.NFCWriteCommand(...)
-    local IRQArrived = q3k.NFCWaitForIRQ()
-    if not IRQArrived then
-        return false
-    end
-    local ACK = q3k.I2CRead(q3k.Config.I2CNFC, 8)
-    if ACK[1] == 1 and ACK[2] == 0 and ACK[3] == 0 and ACK[4] == 255 
-        and ACK[5] == 0 and ACK[6] == 255 and ACK[7] == 0 then
-        return true
-    else
-        return false
-    end
-end
-
-q3k.NFCReadFrame = function(Count)
-    local Bytes = q3k.I2CRead(q3k.Config.I2CNFC, Count+2)
-    table.remove(Bytes, 1)
-    table.remove(Bytes, #Bytes)
-    return Bytes
-end
-
--- Mock until we have a keypad
-q3k.ReadPIN = function()
-    print "[mock] Entering PIN..."
-    q3k.Sleep(2)
-    print "[mock] PIN entered."
-    return { 0, 0, 0, 0 }
-end
-
--- API stuff
-
--- the PIN is a table like { 1, 2, 3, 4 }
--- the NFC ID is a table like { 0xde, 0xad, 0xbe, 0xef }
-q3k.CalculateHash = function(PIN, NFCID)
-    local PINString = string.format("%i%i%i%i", PIN[1], PIN[2], PIN[3], PIN[4])
-    local PINNumber = tonumber(PINString)
-    local IDString = string.format("%02x%02x%02x%02x", NFCID[4], NFCID[3], NFCID[2], NFCID[1])
-    local Source = string.format("%08x:%s", PINNumber, IDString)
-    return sha2.sha256hex(Source)
-end
-
-q3k.GetUserFromHash = function(Hash)
-    local Body, Code, Headers, Status = https.request('https://auth.hackerspace.pl/mifare', 'hash=' .. Hash)
-    if Code ~= 200 then
-        return nil
-    end
-    if #Body > 100 then
-        -- probably an error code
-        return nil
-    end
-    return Body
-end
-
--- debug bytes
-local db = function(Data)
-    local s = ""
-    for _, Byte in pairs(Data) do
-        s = s .. string.format("%02x ", Byte)
-    end
-    print(s)
-end
-
-local main = function()
-    q3k.SetupGPIO()
-    q3k.NFCSendAndAck(0x14, 0x01, 0x14, 0x01)
-
-    while true do
-        q3k.NFCSendAndAck(0x4A, 1, 0)
-        if q3k.NFCWaitForIRQ(120) then
-            print "Card arrived in field"
-            local Bytes = q3k.NFCReadFrame(20)
-            if Bytes ~= nil and #Bytes == 20 then
-                local NFCID = { Bytes[14], Bytes[15], Bytes[16], Bytes[17] }
-                local Hash = q3k.CalculateHash(q3k.ReadPIN(), NFCID)
-                local User = q3k.GetUserFromHash(Hash) 
-                if User == nil then
-                    print "FAILED! no such user!"
-                else
-                    print(string.format("User: %s", User))
-                end
-            end
-        end
-    end
-end
-
-main()
diff --git a/i2c.lua b/i2c.lua
new file mode 100644
index 0000000..dc2fb82
--- /dev/null
+++ b/i2c.lua
@@ -0,0 +1,34 @@
+local i2c = require('libluai2c')
+
+----------------
+-- Public API --
+----------------
+
+q3k.I2C = {}
+
+-- Write to „Address” on the I2C bus
+q3k.I2C.Write = function(Address, ...)
+    local Data = {...}
+    local Bytes = string.format("%02x ", Address)
+    for _, Byte in pairs(Data) do
+        Bytes = Bytes .. string.format("%02x ", Byte)
+    end
+    local DataString = string.char(unpack(Data))
+    return i2c.write(q3k.Config.I2CBus, Address, DataString)
+end
+
+-- Read „BytesOut” bytes from „Address” on the I2C bus
+q3k.I2C.Read = function(Address, BytesOut, ...)
+    local Data = {...}
+    local DataString = string.char(unpack(Data))
+    local Status, Data = i2c.read(q3k.Config.I2CBus, Address, BytesOut, DataString)
+    local Return = {}
+
+    if Status == 0 then
+        Data:gsub(".", function(c)
+            Return[#Return+1] = string.byte(c)
+        end)
+        return Return
+    end
+end
+
diff --git a/main.lua b/main.lua
new file mode 100644
index 0000000..5d72d6d
--- /dev/null
+++ b/main.lua
@@ -0,0 +1,91 @@
+-- The MIT License (MIT)
+-- 
+-- Copyright (c) 2013 Sergiusz 'q3k' Bazański <q3k@q3k.org>
+--
+-- Permission is hereby granted, free of charge, to any person obtaining a copy
+-- of this software and associated documentation files (the "Software"), to deal
+-- in the Software without restriction, including without limitation the rights
+-- to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+-- copies of the Software, and to permit persons to whom the Software is
+-- furnished to do so, subject to the following conditions:
+--
+-- The above copyright notice and this permission notice shall be included in
+-- all copies or substantial portions of the Software.
+--
+-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+-- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+-- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+-- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+-- OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+-- THE SOFTWARE.
+
+-- This is the HSWAW lock mk2. source code.
+
+-- System libraries
+require('posix')
+
+-- Configuration
+q3k = {}
+q3k.Config = {}
+q3k.Config.I2CBus = 0
+q3k.Config.I2CGPIO = 0x40
+q3k.Config.I2CNFC = 0x24
+
+-- Code libraries
+require('i2c')
+require('nfc')
+require('auth')
+
+-- GPIO Functions
+q3k.SetupGPIO = function()
+    -- Set up pins 28, 29, 30, 31 as output
+    q3k.I2C.Write(q3k.Config.I2CGPIO, 0x0F, 0x55)
+    q3k.DoorClose()
+    -- Set up pins 12, 13, 14, 15 as input without pullups
+    q3k.I2C.Write(q3k.Config.I2CGPIO, 0x0B, 0xAA)
+
+    -- Turn on GPIO Multiplexer
+    q3k.I2C.Write(q3k.Config.I2CGPIO, 0x04, 0x01)
+end
+
+q3k.DoorOpen = function()
+     -- Turn on pin 31 (door)
+        q3k.I2C.Write(q3k.Config.I2CGPIO, 0x3F, 0x01)
+end
+
+q3k.DoorClose = function()
+     -- Turn off pin 31 (door)
+        q3k.I2C.Write(q3k.Config.I2CGPIO, 0x3F, 0x00)
+end
+
+-- Mock until we have a keypad
+q3k.ReadPIN = function()
+    print "[mock] Entering PIN..."
+    posix.sleep(2)
+    print "[mock] PIN entered."
+    return { 0, 0, 0, 0 }
+end
+
+local main = function()
+    q3k.SetupGPIO()
+    q3k.NFC.Setup()
+
+    while true do
+        q3k.NFC.WaitForCard(120, function(NFCID)
+            local PIN = q3k.ReadPIN()
+            local Result = q3k.Auth.GetCardStatus(PIN, NFCID)
+            local Status = Result.Status
+            local CS = q3k.Auth.CardStatus
+            if Status == CS.NO_MATCH then
+                print "No such user!"
+            elseif Status == CS.OKAY then
+                print(string.format("Hello %s!", Result.User))
+            else
+                print "Unknown status."
+            end
+        end)
+    end
+end
+
+main()
diff --git a/nfc.lua b/nfc.lua
new file mode 100644
index 0000000..8c8336a
--- /dev/null
+++ b/nfc.lua
@@ -0,0 +1,133 @@
+-- NFC-related functions.
+-- This implementation is for the PN532 chip.
+
+require('socket')
+require('bit')
+
+q3k.NFC = {}
+
+local PN532_PREAMBLE = 0x00
+local PN532_STARTCODE1 = 0x00
+local PN532_STARTCODE2 = 0xFF
+local PN532_POSTAMBLE = 0x00
+
+local PN532_HOSTTOPN532 = 0xD4
+local PN532_PN532TOHOST = 0xD5
+
+------------------------
+-- Internal functions --
+------------------------
+
+-- sigh. luaposix on openwrt doesn't have nanosleep()
+local Sleep = function(Seconds)
+    socket.select(nil, nil, Seconds)
+end
+
+-- Get the IRQ pin status
+local IRQRead = function()
+    local Data = q3k.I2C.Read(q3k.Config.I2CGPIO, 1, 0x2C)
+    if Data then
+        return Data[1]
+    else
+        return 1
+    end
+end
+
+-- Wait „Timeout” seconds for IRQ (or 5, if not given)
+local WaitForIRQ = function(Timeout)
+    local Timeout = Timeout or 5
+    local WaitStart = os.time()
+    while os.time() < WaitStart + Timeout do
+        local IRQStatus = IRQRead()
+          if IRQStatus == 0 then
+            break
+        end
+        Sleep(0.2)
+    end
+    local IRQStatus = IRQRead()
+        if IRQStatus ~= 0 then
+                return false
+        end
+    return true
+end
+
+-- Write a PN532 command
+local WriteCommand = function(...)
+    local Command = {...}
+    local Checksum = PN532_PREAMBLE + PN532_STARTCODE1 + PN532_STARTCODE2
+    local WireCommand = { PN532_PREAMBLE, PN532_STARTCODE1, PN532_STARTCODE2 }
+
+    WireCommand[#WireCommand+1] = (#Command + 1)
+    WireCommand[#WireCommand+1] = bit.band(bit.bnot(#Command +1) + 1, 0xFF)
+
+    Checksum = Checksum + PN532_HOSTTOPN532
+    WireCommand[#WireCommand+1] = PN532_HOSTTOPN532
+
+    for _, Byte in pairs(Command) do
+        Checksum = Checksum + Byte
+        WireCommand[#WireCommand+1] = Byte
+    end
+
+    WireCommand[#WireCommand+1] = bit.band(bit.bnot(Checksum), 0xFF)
+    WireCommand[#WireCommand+1] = PN532_POSTAMBLE
+
+    q3k.I2C.Write(q3k.Config.I2CNFC, unpack(WireCommand))
+end
+
+-- Send a PN532 and see if we get an ACK
+local SendAndAck = function(...)
+    WriteCommand(...)
+    local IRQArrived = WaitForIRQ()
+    if not IRQArrived then
+        return false
+    end
+    local ACK = q3k.I2C.Read(q3k.Config.I2CNFC, 8)
+    if ACK[1] == 1 and ACK[2] == 0 and ACK[3] == 0 and ACK[4] == 255
+        and ACK[5] == 0 and ACK[6] == 255 and ACK[7] == 0 then
+        return true
+    else
+        return false
+    end
+end
+
+-- Read a PN532 frame
+local ReadFrame = function(Count)
+    local Bytes = q3k.I2C.Read(q3k.Config.I2CNFC, Count+2)
+    table.remove(Bytes, 1)
+    table.remove(Bytes, #Bytes)
+    return Bytes
+end
+
+----------------
+-- Public API --
+----------------
+
+-- Call this once the I2C bus and GPIO multiplexer are ready
+q3k.NFC.Setup = function()
+    -- enable SAM with stuff.
+    if SendAndAck(0x14, 0x01, 0x14, 0x01) == false then
+        print "SAM configuration failed!"
+        return false
+    end
+    return true
+end
+
+-- Waits for a NFC card to appear in the field
+-- „Seconds” is how long the reader will block
+-- „Callback” is a callback which is called when a card appears, and takes
+-- a single argument which is the NFC ID like this: { 0x00, 0x01, 0x02, 0x03 }
+q3k.NFC.WaitForCard = function(Seconds, Callback)
+    if SendAndAck(0x4A, 0x01, 0x0) == false then
+        print "Sending card read command failed!"
+        return false
+    end
+    if WaitForIRQ(Seconds) then
+        local Bytes = ReadFrame(20)
+        if Bytes ~= nil and #Bytes == 20 then
+            local NFCID = { Bytes[14], Bytes[15], Bytes[16], Bytes[17] }
+            Callback(NFCID)
+        end
+        return true
+    end
+    return true
+end