K1C smart upgrades

Three upgrades that connect the K1C to the rest of the house. Moonraker reports the printer state, n8n turns it into MQTT commands, and a Thread border router passes them to ESP32 boards as Matter devices.

Print status light

An LED strip inside the lid riser, pointing down at the bed. An ESP32-H2 drives it, and the colour follows the printer state.

Parts: WS2812B strip at 30 LEDs per metre, 5 V from a buck converter off 12 V, and an SN74HCT125N level shifter because the ESP32 speaks 3.3 V and the strip wants 5 V. The antenna goes near the plastic panels, since the metal frame blocks the Thread signal.

Automatic fume extraction

An inline 120 or 140 mm PWM fan at the window end of a 100 mm duct from the K1C's rear exhaust. The ESP32-H2 shows up in Matter as a fan, so voice assistants can control it too.

The extractor follows the printer's own exhaust fan, scaled by material:

Open points: too much pull cools the chamber and warps ABS, so n8n needs a heat limit. A pressure sensor could flag a clogged carbon filter, an SGP40 VOC sensor could start the fan on its own, and the fan should run at 30% for 10 minutes after each print.

Secondary camera

An ESP32-CAM with a wide 120° or 160° lens in the rear left corner, looking at the nozzle's home position, in a printed bracket.

The chamber gets above 60 °C, which is hard on the camera, so it sleeps until asked. A page sends a "knock" over MQTT; the camera wakes, streams over RTSP for 30 seconds, and goes back to sleep unless another knock arrives within 25 seconds.

An n8n workflow can also knock every 30 seconds during a print and join the photos into a timelapse.