Assembly and verification

Assembly

1. Case. A box with two openings: air inlet and outlet. Print for your filter cartridge or modify a ready-made one.
2. Layer order by air flow: inlet → HEPA → carbon → fan (as exhaust) → outlet. Joints without gaps: air is lazy and will bypass the filter if it can.
3. Sensor — on the inlet flow, before the filters: it should smell the room's dirty air, not the cleaned one.
4. Electronics — in a separate compartment or on the wall, away from the dust flow. Board — on spacers, not "loose."
5. Secure the wires: fan vibration will loosen anything not secured over time.

Complete checklist

Check in order — each point depends on the previous ones.

#	Check	How
1	Power	12V on fan line, 5V after buck, 3.3V on sensor
2	Sensor alive	in Serial log index ~100 in clean air, grows from breath
3	Device Online	status on portal after PIN linking
4	Telemetry	vocIndex and fanStatus in device stream
5	Card	VOC and Fan cells, Mode list, Threshold field
6	Command from portal	Mode → on: fan turned on, card shows "On"
7	Automation	Mode → auto, breathe: turned on at threshold, turned off below
8	Reboot	mode and threshold saved, card came alive by itself

What's next

Filter is ready. Next — your choice:

• More entities: button "purge 5 minutes" (card().button(...)), second sensor, fan hours counter with replacement reminder;
• Nice layout: factory layoutRow you already saw; card will also be layout-editable in the portal editor;
• Your devices: this whole section is a template. Replace the sensor, actuator, and logic — and by the same scheme assemble a humidifier, exhaust, controller of anything. The manifest will build the interface itself.

If something doesn't start — Common Mistakes.