Boilerplate for NodeMCU

more on https://koscis.wordpress.com/tag/nodemcu-boilerplate/

Core

• init.lua - run automatically
• parameters.lua - project configuration (AP login, password, protocol version)
• parameters-device.lua - this unit configuration (like node name)
• wifi-init.lua - WiFi connection and keep alive timer
• main.lua - main code for app
• network_message.lua = module to decode and validate network packet to JSON message

init.lua

This one is simple. Quick check for D1 / GPIO5 state. If it is connected we will abort app and if not we start wifi-init.lua.

parameters*

Remove .dist. In parameters.lua keep project variables like access points login, some pin mapping, global names. In parameters-device.lua some configuration that belongs to this node. Like its name or some id

wifi-init

Idea is simple, check if we are already connected and if not we iterate over APs and we use timer to check status. After getting connection we launch main.lua and start keep-alive-timer.

I had few cases when net was gone and board didn't reconnect until rebooted. After few tries I ended with timer that checks connection and count failures in row. After reaching 10 or more it force unit reboot. Normally board would reconnect automatically before time is out. In my case it was ok to reboot the device but keep in mind that may not be in yours.

If you want to use wifi-init with triled use file wifi-init-triled.lua. Remember to rename it.

main

This file is main app start file. In boilerplate we will just turn on buildin led.

Modules

network_message

Module to work with JSON messages. For communication between nodes I use JSON messages. Such message looks like this:

{
    protocol: "iot:1",
    event: "channel1.on",
    node: "computer",
    chip_id: "some id",
    response: "some response"
    targets: [
       "big-room-support-light"
    ]
} 

Fields protocol, event or response are required. Server also check if its node name is in targets table. If you want to send message to all nodes set targets: ['ALL'].

Module functions:

• decodeMessage(message) - decode and validate string into message. on fault returns nil Sample

• prepareMessage() - returns table with set fields protocol, node, chip_id, event='', response='', targets=['ALL'] Sample

• sendMessage(socket, message) - message is a table, function convert it to json string and send to socket

Read more

Event listener (runs handlers)

Module to handle events. It start its own UDP server, receive packet. Next it transform it into message and pass to registered handlers. Each handler reacts on supported events by executing some actions on its worker.

Handler is a module that understand message and can execute events.

    server_listener = require "server_listener"
    (...)
    -- add handlers to listener
    server_listener.add("lcd", lcd_handler)
    server_listener.add("thermometer", temp_handler)
    
    -- run server
    server_listener.start(PORT)

See handlers and events in modules/workers.

Worker lcd_hd44780 + handler

Module to utilize char display based on hd44870. Works with 16x1 up to 40x4

• Default wiring GPIO:

    drv.pins = {
        RS= 7,
        E1= 6,
        E2= nil,
        DB4= 5,
        DB5= 3,
        DB6= 1,
        DB7= 2,
    }
  

• Default i2c:

    drv.pins = {
        RS= 4,
        E1= 5,
        E2= nil,
        DB4= 0,
        DB5= 1,
        DB6= 2,
        DB7= 3,
    }
  

• use with default pins and 16x2 size, direct

    hd44780 = require("lcd_hd44780")
    driver = require("lcd_hd44780_gpio")  <-- GPIO
    driver = require("lcd_hd44780_i2c")  <-- I2C
    
    drv = driver()
    drv = driver(0x20, 4, 5) <--i2c & default pins
    
    pins = {
        RS= 4,
        E1= 5,
        E2= 6,
        DB4= 0,
        DB5= 1,
        DB6= 2,
        DB7= 3,
    }
    drv = driver(0x20, 4, 5, pins) <--i2c & set pins
    
    lcd = hd44780(16, 2, drv, 'direct', 1, 1)
    lcd:init()
    lcd:write('Zombicide')
    lcd:set_xy(0, 1)
    lcd:write('Black Plague')
  

• use with default pins and 40x4 size, buffered

    hd44780 = require("lcd_hd44780")
    drviver = require("lcd_hd44780_gpio")  <-- GPIO
    drviver = require("lcd_hd44780_i2c")  <-- I2C
    
    drv = i2c_driver(0x20, 4, 5, pins)
    lcd = hd44780(40, 4, drv, 'buffered', 1, 1)
    lcd:init()
    lcd:set_xy(0, 0)
    lcd:write("The cat")
    lcd:set_xy(0, 1)
    lcd:write("and meows")
    
    lcd:flush()
    lcd:set_xy(10, 0)
    lcd:write("purrs")
    
    lcd:flush()
  

Read more

i2c_scan

Scans for I2C devices. Default SDA = D1 and SCL = D2. Usage:

    i2cscan = require "i2c_scan"
    i2cscan.scan()    

Want to use different pins, set them before scan:

    i2cscan.pins = {
        sda = 1,
        scl = 2
    }
    i2cscan.scan()

Output is similar to this:

         0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
    00: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
    10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
    20: 20 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
    30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
    40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
    50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
    60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
    70: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --    

Worker 18b20 temperature sensor + handler

     pin = 3 -- 1-wire bus
     temp = require "18b20"
     print(temp.get_temperature()) 

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Worker and handler for relays

Controls the relays. CHANNELS is a table with gpios that are used to enable relay signals.

    CHANNELS = {2, 3, 4, 1}
    relay_handler = require "relay_handler"
    handler = relay_handler(CHANNELS)

    -- add handlers to listener
    server_listener.add("relay", handler)

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Worker and handler for PIR HCS-SR501

Motion detector

    pir = require "pir_hcs_sr501"
    pir_handler = require "pir_hcs_sr501_handler"
    send_socket = net.createUDPSocket() 
    sensor = pir(send_socket, 2)
    handler = pir_handler(sensor)
    server_listener.add("pir", handler) 

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Worker and handler for light detector, without callback

    light_sensor = require "light_detector"
    light_sensor_handler = require "light_detector_handle"
    send_socket = net.createUDPSocket() 
    light = light_sensor(send_socket, 4, nil, 1600)
    light_handler = light_sensor_handler(light)
    server_listener.add("light", light_handler)

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Worker and handler for DHT11

    dht11 = require "dht11"
    dht11_handler = require "dht11_handler"
    mydht = dht11(5)
    dht_handler = dht11_handler(mydht)
    server_listener.add("dht", dht_handler)

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Worker for sound detector

    sd = require "sound_detector"
    gpio.mode(3, gpio.OUTPUT, gpio.PULLUP)
    gpio.write(3, gpio.HIGH)
    local bum = false
    
    sound_detector = sd(send_socket, 1, function(event)
        if bum then
            gpio.write(3, gpio.HIGH)
        else
            gpio.write(3, gpio.LOW)                
        end
        bum = not bum
    end) 

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Triled module

Module to control triled or any other with common anode.

    triled = require "triled"

    triled.pin_red = 2
    triled.pin_green = 1
    triled.pin_blue = 8
    triled.init()
    
    triled.red(true)
    triled.blink_green(2)
    triled.blink_blue(3, true)

If you want to use wifi-init with triled use file wifi-init-triled.lua. Remember to rename it.

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RFID - RC522 module and handler

    rc522_handler = require "rc522_handler"
    rc522 = require "rc522"
    handler = rc522_handler(function(event, params)   
        if rc522.last ~= nil and params.id == rc522.last then
            print(params.id)
            print(params.response)
            rc522.last = ""
        end
    end) 
    rc522.pin_ss = RC522_PIN_SS
    rc522.pin_rst = RC522_PIN_RST
    rc522.init(function(cardid) 
        print("Tag Found: "..cardid)
    end) 

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