ESP32 powered ePaper Dashboard Controlled via MQTT
I built this because I never got the idea of all the other single-purpose ePaper projects out there. So many need an overpowered RPi attached to them, others have very specific code running on Arduino code. I really want the ePaper as a generic display output for other systems, and change it regularly.
It seems that all the displays typically achieve are a bunch of rectangles with text over the top of them (a line is just a 1px rectangle).
So this project allows you to construct a simple screen layout by passing in an array of rectanges to draw backgrounds and lines, followed by a number of strings for text to write over the top.
I use this on my 7.5" Waveshare black&white display. Aiming to have this powered by battery one day. Really designed for my purposes, but feel free to use or steal code if it suits yours too.
NOTE: I have no experience with Arduino code and haven't used C in almost 20 years, apologise for the hacky code. This will probably change regularly in a breaking way. Clone it if you care.
Send an event to esp32/output with a JSON payload. MQTT payload is limited to a predefined buffer size. If you are sending large packets you might need to increase that size.
Examples...
Minimum:
{
"strings": [
{
"x": 100,
"y": 100,
"message": "Hello world"
}
]
}Full:
{
// Screen rotation: 0|1|2|3
"rotation": 0,
// Partial refresh
"partial": true,
"rectangles": [
{
// Box
"x": 0,
"y": 0,
"w": 800,
"h": 50
},
{
// Line
"x": 400,
"y": 0,
"w": 1,
"h": 480
},
{
// White Line
"x": 0,
"y": 25,
"w": 800,
"h": 1
}
],
"strings": [
{
// Note x,y represents the bottom-left position of the first character, not the top-left
"x": 100,
"y": 450,
"message": "Hello world"
},
{
// Strings are written last, so white text over black rectangle is readable
"x": 100,
"y": 25,
"message": "Hello world",
"color": "white",
"font": "azonix36"
}
]
}The fonts are embedded. You have to change the code if you want new fonts. Use fontconvert to make new fonts.
Current fonts:
"robotothin72"Roboto font, thin variant, 72pt"azonix36"Azonix font, 36pt
Use "black" or "white". I haven't supported 3 color displays since I don't have one.
Defaults to "black" if not specified.
Credentials are hard-coded. Edit network.h to configure.
- Allow for text to be centred.
- Allow for bitmaps.