Tag Archives: raspberry pi

Conways Game of Life

Working on a new project, combining making something fun with learning some new skills. In this instance the primary goal was to learn a little more about python, Visual Studio Code + Github, and object oriented programming (my first class!).

Sneak peek below, but this will be a RGB 48*48 matrix framed in a shadow-box on the wall. Initially it’ll run the game of life, but could be updated later to display anything. Early pics of the physical project below, and link to gitHub repository.

Publishing IoT IP Addresses to MQTT

I have been playing around with using ESP8266’s as endpoints around the house for collecting temperature, turning the sprinkler pump on, texting me when the doorbell is pressed, etc.  One of the challenges when doing setup/testing is getting the IP address of them when they first come online.

I am running dnsmasq on a raspberry pi, which provides both local DNS and DHCP services.  This is in no way novel, as it is a pretty vanilla configuration.  What I wanted to share is a small script that monitors for updates to the dnsmasq log, watches for new client releases/renewals and then posts those to the MQTT service.  There are lots of things you can do with it from there, but I usually just subscribe to the topic via terminal or mqtttool on my iPhone.

#!/usr/bin/python
from pygtail import Pygtail
import sys
import re
import time
import paho.mqtt.client as mqtt

client = mqtt.Client()
client.username_pw_set("xxxxxx","xxxxxx")

while (1):
 for line in Pygtail("/var/log/dnsmasq.log"):
   isItACK = re.search(r'DHCPACK',line)                #see if its an ACK
   if isItACK:
     newInput = re.sub(r'^.*DHCPACK\(eth0\).', "", line) #strip everything before mac address
     newInput = newInput.rstrip()                        #strip newlines
     client.connect("xxxxxx.widgetninja.net",1883)       #connect to mqtt
     client.publish("/network/DHCP",newInput)            #publish to mqtt
     client.disconnect                                   #hang up
     #sys.stdout.write(newInput)                         #debugging
 time.sleep(10)

Hope this helps save you some time trying to find the ip address of that new device, be it something you made or otherwise just added to your network.

mqtt