Introduction: Simple Moving Message WIFI Display Using MQTT and D1 Mini
This is a simple moving message WIFI display, We are just using 3 pieces of hardware - and can really get away with just two pieces.
You will need some basic soldering skills for putting the pin headers on the D1 Mini, and shields.
I generally find prices for the D1 Mini a bit better on Aliexpress, but feel free to source your own parts.
Required Hardware: (Dollars are in U.S. Dollar)
D1 Mini - About $2.55 https://www.aliexpress.com/item/1pcs-Smart-Electro...
Matrix LED Shield - About $1.60 - https://www.aliexpress.com/item/Matrix-LED-Shield-...
Not required but maybe handy to have:
Dual Base Shield - About $.50 - https://www.aliexpress.com/item/Double-Socket-Dual...
About $4.65 total.
Some optional hardware:
For power I keep it very simple, and used the USB port on the D1 - a cell phone charger, or just plugged into the USB port on a computer works well.
However Wemos does have a couple of other power options,
Battery Shield - About $1.10 - https://www.aliexpress.com/item/WeMos-D1-Mini-Batt...
(You will need a LiPO battery which will add some cost to the project)
DC power shield - About $2.11 - https://www.aliexpress.com/item/DC-Power-Shield-V1...
Skills and tools needed:
A basic soldering iron, and some basic solder skill will be needed. That is really it.
Once the pins are soldered on to the boards, you just need to plug the matrix shield into the D1 mini. The only note here is there is a little "dot" on the matrix shield, there is also a dot on the D1 mini (or there should be) - match them, and plug it in.
Step 1: Grab the Code, Setup the Arduino IDE, and Program!
The Code can be found here: https://github.com/kd8bxp/Simple-Moving-Message-WI...
There are a few libraries that also need to be installed, and if you haven't done so - you will need to install the ESP8266 boards into the Arduino IDE.
Follow the instructions here to add the boards:
We need to included a wemos_matrix_gfx library made by Thomas Fredericks. This really couldn't have been made without his library. I also submitted a couple of "examples" for him to include in the examples. You should check those out too! I'm almost positive you'll have to install this manually - either by using the "Add .ZIP file" or just unzip/rename the folder, and copy it to the libraries directory in your Arduino folder.
The other libraries you will need are in the library manager - so they should be easier to install.
Adafruit_GFX library more information can be found here: https://github.com/adafruit/Adafruit-GFX-Library
and PubSubClient library https://github.com/knolleary/pubsubclient
Once you have all that installed, open my sketch: d1_mini_matrix_wifi_display.ino
Near line 40 you'll find where you need to put your router informations - SSID, and PASSWORD.
I am using a public MQTT broker (test.mosquitto.org) it's not secure so don't send anything sensitive. If you wish to use your own broker, or a different broker - you can change that here.
(See my instructable on using a Raspberry PI Zero W as a AP and MQTT Broker if you want to set up your own broker)
It is also probably a good idea to change the "subTopic" - on line 45. Otherwise your display could display messages you don't to see. And you could publish messages to other peoples displays.
Want to learn a bit more about MQTT - I have a previous project that I explain it a bit more found here:
ESP32/ESP8266 WIFI Display Using MQTT Protocol. (step 4 & 5)
Briefly MQTT is a simple publish/subscribe lightweight messaging protocol designed for constrained devices and low bandwidth, high latency or unreliable networks. Making it nice for IoT devices.
Step 2: Publish Your Message.
In order to publish your message you need a MQTT client, there are a lot of them out there. And even some that have a web interface (using Websockets) - I go into great detail on installing and using a MQTT broker in my previous WIFI display instructable. (step 5). Let's keep it simple, and use a Websocket.
http://test.mosquitto.org/ws.html you'll see a "connect" button, a 'Topic' form, and a 'Payload' form. (Payload = message). You'll want to make sure you are connected to the broker, type in your topic name (matrixDisplay10), and type your message into the payload. Click publish and you should see a message on your display.
In the picture above I am using the linux mosquitto client, The idea is the same -
mosquitto_pub -h test.mostquitto.org -t "matrixDisplay10" -m "This is a message"
That is about it, a nice simple Matrix WiFi Display....I hope you enjoy. Thank you!