GMail notifier with ESP8266 / NodeMCU

A while back I investigated the use of NodeMCU with GMail. One result was this script to send mails over GMail. The other aspect I initially didn't fully investigate was the atom feed offered by GMail.

Looks like we have unread mail

If you haven't watched the video yet, here it is.

In the code below, I use that feed to retrieve the number of unread elements from the inbox.
Apart from the Lua code, you also need to place the two files with the mailbox icons on NodeMCU's file system:

Mailoff-file: here
Mailon-file: here

That is what it looks like in action:

I recommend "esplorer" to copy the files to the ESP8266 module.

 -- ESP8266 NodeMCU  

 -- GMail Notifier  
 -- 2016/07 Andy Reischle  
 -- www.AReResearch.net  
 -- Graphics handling and conversion  
 -- adapted from Daniel Eichhorns blog  
 -- http://blog.squix.org/2015/05/esp8266-nodemcu-how-to-create-xbm.html  
 --  
 -- To see this script in action, see:  
 -- https://youtu.be/IVxJosLZCXs  
 wifi.setmode(wifi.STATION)  
 wifi.sta.config("YOUR-SSID","YOUR-WIFIPASS")  
 wifi.sta.connect()  
 -- setup I2c and connect display  
 function init_i2c_display()  
    -- SDA and SCL can be assigned freely to available GPIOs  
    sda = 5 -- GPIO14  
    scl = 6 -- GPIO12  
    sla = 0x3c  
    i2c.setup(0, sda, scl, i2c.SLOW)  
    disp = u8g.ssd1306_128x64_i2c(sla)  
 end  
 function xbm_picture()  
    disp:setFont(u8g.font_6x10)  
    disp:drawStr( 0, 62, "Google Mail Notifier")  
    disp:drawXBM( 10, 5, 32, 32, xbm_data )  
    disp:drawStr (65,30, unread .. " unread")  
 end  
 function bitmap_mailon(delay)  
    file.open("mailon", "r")  
    xbm_data = file.read()  
    file.close()  
    disp:firstPage()  
    repeat  
       xbm_picture()  
    until disp:nextPage() == false  
    tmr.wdclr()  
 end  
 function bitmap_mailoff(delay)  
    file.open("mailoff", "r")  
    xbm_data = file.read()  
    file.close()  
    disp:firstPage()  
    repeat  
       xbm_picture()  
    until disp:nextPage() == false  
    tmr.wdclr()  
 end  
 init_i2c_display()  
 function checkmail()  
 user="YOURADDRESS@GOOGLEMAIL.COM"  
 pass="YOURGMAILPASSWD"  
 b64 = crypto.toBase64(user .. ":" .. pass)  
 -- print (b64)  
 local LED_PIN1 = 4   
 gpio.mode(LED_PIN1, gpio.OUTPUT)  
 conn=net.createConnection(net.TCP, 1)  
 conn:on("receive", function(sck, c)  
 -- print(c)  
 start1,stop1=string.find(c,"<fullcount>")  
 start2,stop2=string.find(c,"</fullcount>")  
 if start1 then  
   unread=string.sub(c,stop1+1,start2-1)  
   print ("Found " .. unread .. " unread Mails.")  
    if tonumber(unread) > 0 then  
         gpio.write(LED_PIN1, gpio.LOW)  
         conn:close() -- we got what we came for, so close  
         bitmap_mailon()  
     else   
         gpio.write(LED_PIN1, gpio.HIGH)   
         conn:close() -- no Mail, so close  
         bitmap_mailoff()  
    end  
  end  
 end )  
 conn:on("connection", function(conn)  
    print("connected")  
    conn:send("GET https://mail.google.com/mail/feed/atom/ HTTP/1.1\r\n" ..  
        "Host: mail.google.com\r\n"..   
        "Authorization: Basic " .. b64 .. "\r\n" ..  
       "User-Agent: Mozilla/4.0 (compatible; esp8266 Lua;)"..  
        "\r\n\r\n")   
 end )  
 conn:on("disconnection", function(conn) print("disconnected") end )  
 conn:connect(443,"mail.google.com")  
 end  
 tmr.alarm(0,30000,tmr.ALARM_AUTO,checkmail)  

Not much stuff is needed for that little project:

• a breadboard
• this ESP8266 dev board leaves free holes on the side of the breadboard 
• I used the I2C version of the OLED module
• and a couple of dupont jumper wires

Assembly is done in no time at all. Just connect power and I2C leads. (For me, this works without pull-up resistors.)

Not a lot to do.