Fan sled for smart vents without ductwork (auto on/off)

thingiverse

Original files in Onshape: https://cad.onshape.com/documents/f6068ee2ed83c3c456cfc910/w/bde2fd8ffe8e3a81a93fe971/e/62f670e7a891711b4d643dde?renderMode=0&uiState=626d9b05c8b539711c985bf5 _(This project is considered "Beta", ie it works well enough that I've been able to print and assemble a working final product. Tolerances can be improved, quality of life changes could be added, but I've spent several months on this and want to be _finished_. Snap-fit parts likely won't fit _quite_ right, and things like the contacts on the vent attachment are probably unnecessarily complicated. But it works! Good enough for me.)_ This is a set of models for assembling a fan sled to generate airflow behind a smart vent without any ductwork. The main fan sled should be usable for any smart vent, but the "Keen Vent Attachment" model is specific to the 12x4 Keen Vent. Video demonstration: https://youtu.be/Zpynj1eS8lM The main features are: - Fans can turn on/off automatically when the vent opens/closes - No wiring needed for attaching the fan sled to the vent - Airflow can be reversed by simply detaching the sled from the vent attachment, flipping the sled, and reinserting The auto on/off is handled by a reed switch attached to the vent, and a magnet attached to the fins to toggle the switch. This is connected to the "Vent Attachment" which has contact points for providing power to the fans, and guides for running power cables without snagging on the fan sled. The Keen Vent Attachment has holes placed so that the holes in the vent can be removed, attachment placed, and screws re-inserted to hold it securely. The contact points on the attachment have 7 holes for passing through each strand of a 7-strand wire. (See pictures.) Required parts for the fan sled: - 1x Active and Inactive Front + Back - 4x rod clip top - 3x 80mm fans per fan sled - 4x 2.5mm-diameter aluminum rods per vent, 15-18mm long (I used rivets cut in half) (for contacts on the sled itself) - An external power supply to power the fans (24V in my case) - 3D printer pen for "welding" the different parts together Required parts for the vent attachment: - 1x Keen Vent Attachment - 1x normally-closed (NC) reed switch and magnet per vent - 20AWG 7-strand copper wire I also recommend a PWM controller so your fans aren't forced to run at 100% speed, eg https://www.amazon.com/gp/product/B081LYC7BG I used: - Fan - https://www.digikey.com/en/products/detail/orion-fans/OD8025-24HSS/2621167 (80x25mm 24V) - Reed switch - https://www.digikey.com/en/products/detail/pic-gmbh/PMC-1001THY/9687556 - Magnet - https://www.digikey.com/en/products/detail/comus-international/RSH01/11562479