In the first season of stranger things, a character uses a string of Christmas lights to communicate with a missing loved one. The missing person in question can flash particular lights next to letters painted on a sheet to spell out messages. Christmas lights and bedsheets have become part of pop culture and because the sight is spooky, Redditor BishSaidWut’s recreation is the perfect Halloween decoration.
Unlike most similar decorations you can buy online that flash randomly or spell out pre-programmed messages, BishSaidWut’s Christmas lights can spell out any message they text to a specific phone number. This phone number connects to the Twilio service, which parses SMS messages and makes the text available through an API. An ESP8266 board connects to this API and processes incoming messages. If the message is within an acceptable length and does not contain profanity, the ESP8266 passes the text to an Arduino Uno board.
The Arduino controls the real Christmas lights. It buffers the text strings it receives from the ESP8266 and starts animating a new message as soon as the last one is finished. The Christmas lights are all individually addressable RGB LEDs, so the Arduino simply illuminates the LED next to each letter in the correct order. BishSaidWut has set this up for SMS control so they can post new messages whenever they want and they are even considering posting the phone number so others can send their own messages while BishSaidWut broadcasts the results.