My Smart Home has grown into a Frankenstein monster.
I started with Node-Red and Mosquitto MQTT broker on a single Raspberry Pi3. At some point I wanted to add some Z-Wave devices and someone on the Node-Red forums told me that my best route was to install Home Assistant and an Aeotec Z-Stick, then I could control the Z-Wave devices from Node-red. I didn't want to risk messing up my currently running Pi with Node-red and Mosquitto, so I installed Home Assistant on a second Raspberry Pi. I discovered that I like Home Assistant and instead of growing my system on Node-Red, as originally planned, I spent the next months adding more devices to Home Assistant.
So now I had two Raspberry Pis running my smart home. Then came the Tradfri lights, so add the Tradfri Gateway to the mix. Next, I added some IP cameras.
So when my wife says that "Alexa isn't listening to me!", I have a number of places to look for the problem. (Since I am always doing something to my stuff, I am always breaking something).
My troubleshooting process involves pinging all the likely suspects to make sure they are all online. I wanted a faster and easier way to determine where to start looking for a problem. Thus was born my Net Monitor Applpiance project.
The Net Monitor Appliance just pings the IP address of the critical devices on my network, and if a good ping is found, lights a green LED. If a ping is not responsive, a red LED lights. The loop repeats every 30-seconds. So, if I look up and see a "green board", then I know not to take the time to ping up to 10 devices.
I chose to make the Net Monitor on the NodeMCU platform because it has WiFi and works from any 5V micro-USB wall wart. I could have easily included an LCD display, but I just wanted to have something to determine at a glance if I have a net problem.
Check out a different esp8266ping.h library https://github.com/dancol90/ESP8266Ping/blob/master/examples/SimplePing/SimplePing.ino