I got the idea for this old school style display when I first saw the most excelent Arduino plug-in for HomeSeer Home Automation software by Greig Dempster. This plugin supports a number of different boards. I choose the Node-MCU for this project because of the integrated WiFi and the many reports of how stable it is. I have an extensive Homeseer installation but I have found that I have a small number of devices that I would like to have a constant status display for. Such as the status of the Washing Machine and the Water Pump for the house. I have Vibration sensors on both so Homeseer knows when they are running or not. There are many ways for Homeseer to display status but I wanted to do something unique and I have always liked the look of the old school Nasa inspired back-lit displays that were dedicated to a single message using a stencil as a shadow mask to create the message. The first thing I had to do was to be sure my Ultimaker 2+ was up to the task of creating a readable light stencil and to determine the size that I would need to make it readable. I printed a proof of concept square tube with an LED mounted at one end and a "Hello World" light stencil on the other. This first attempt was approx 25mm square and while it was readable I decided to make the final version a little larger to give me room for a few more letters and to make each display larger so it would be readable from a further distance. The final dimensions are 39mm square for the outside of each display segment. As I was going for an old-school look I didn't mind it being a little "clunky". I came up with a way to sandwich 6 display segments between a front and back clam-shell housing using 4 standoffs to provide the mechanical strength for the 4-40 button head screws. This also made it easy to remove the front Clamshell to replace a light-stencil if I want to change out the message. The back clam-shell was made to mount the Node-MCU board upside down so I could easily attach a wire from each LED and also access the power connector through a hole in the side of the case. A thin RED Acrylic sheet (Plexiglass) to hide the messages when there was no back-light and give it a nice look on the front. After that It was a simple matter to configure the Node-MCU to communicate with Homeseer using Greig Dempster Arduino plugin. I created events to monitor 6 different sensors and to turn on and off the corresponding LEDs in the Annunciator. It has been running for over a week now and has been very reliable. Now with just a glance at the Annunciator panel I can know when the Washing machine has stopped and needs attention as well as the current state of 5 other devices. The Arduino Plug-in support a large number of Node-MCU boards at one time so I could easily create a very large status display or scatter several around the house as needed.