3D printing is one of those "hurry up and wait" kinds of activities. It takes time to setup and start a print, then make sure the first layer goes down well. After that, it becomes a waiting game. But you can't give all of your attention to something else while you wait, because the printer may need intervention. For that reason, many of us have cameras to monitor our printers and notifications setup. Simit went a couple of steps further and repurposed decorative LED panels to provide obvious indications of several 3D printers' statuses.
Simit has six 3D printers and it can be difficult to keep an eye on all of those at the same time. These LED panels make that job much easier. Each corresponds to one of the 3D printers and its color conveys the status of that printer. The number of LEDs lit on each panel can also provide additional information, like the progress of a print job. Because the panels look nice, Simit can mount them on a wall as decor. That ensures that they're always within sight, letting Simit go about their day with the confidence that they'll notice when a printer needs attention.
This project started with The Hexes, designed by DeDane1970. Those are the decorative hexagonal LED panels, which would normally act as simple wall art. An ESP32 development board controls the WS2812B individually addressable RGB LED strips that follow the inside borders of the panel hexagons. If Simit only wanted wall art, they could have stopped there and set the ESP32 to run some animation effects. But they wanted the LEDs linked to the 3D printers and that required an intermediary.
A low-cost Mini PC tells the ESP32 how to set the color and brightness of the LEDs. It runs Home Assistant, which is home automation software that has a plugin available for Moonraker. Moonraker is an interface for Klipper 3D printer firmware. Because Moonraker knows the detailed status of each 3D printer, it can send specific information (like print progress) through Home Assistant to the ESP32. The number of lit LEDs and their color are enough to convey crucial information. Simit could, for example, set it so that a panel starts flashing red if a printer throws an error, or to glow a pleasant blue when a print job finishes.