My MQTT network at home moves up and down a lot of messages: sensor values, triggers, notifications, device statuses,… I use Node-RED to forward the important ones to PushOver and some others to a Blynk application. But I also happen to have an LED display at home and that means FUN.
LED displays are cool. Your team’s score, your number in the IRS queue, the estimated arrival time for your next commute,… Now that TVs are replacing LED displays (like the later did with the electromechanical ones) they have acquire an almost vintage-status.
This LED display I own even has a name: The Rentalito. The Rent Alito is an old friend, one of those projects you revisit because LED displays are cool… Originally it was an Arduino Uno with an Ethernet Shield in a fancy cardboard case. Then it went WiFi using a WiFly module. And then a SparkCore replaced the Arduino. Now… well, ESP8266 is driving my life.
Let me introduce you the latest iteration of the Rent Alito, the MQTT LED matrix display.

The board

Nothing special about the board. A power jack, a regulator, the ESP12 module and the shrouded header for the display flat cable. I brought out VCC, GND, RX and TX to be able to program the ESP8266 the first time, from there on OTA is my preferred way: its a lot faster, specially when uploading the file system. A couple of buttons allow me to reset the controller and pull down GPIO0 to enter flash mode. They are mostly intended for development.
Like in the previous version I’ve added an IR receiver and a DHT22 temperature and humidity sensor. The DHT22 is completely optional, the IR receiver is meant to be able to set the device in sleep mode, so it would only display priority messages.

Soldering SMD parts

Most of the parts are SMD. I wanted to gain some practice soldering them and I wanted to keep the board under 50x50mm (cheaper to fab) while soldering parts only on one side of it.
Read More: 64×16 MQTT LED Matrix Display