Documented USB desk fan mod

[physical.git] / misc / USB desk fan mod / index.org

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+#+TITLE: USB desk fan modification
+#+author: Svjatoslav Agejenko
+#+LANGUAGE: en
+
+* (document settings) :noexport:
+** use dark style for TWBS-HTML exporter
+#+HTML_HEAD: <link href="https://bootswatch.com/3/darkly/bootstrap.min.css" rel="stylesheet">
+#+HTML_HEAD: <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
+#+HTML_HEAD: <script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.5/js/bootstrap.min.js"></script>
+#+HTML_HEAD: <style type="text/css">
+#+HTML_HEAD:   footer {background-color: #111 !important;}
+#+HTML_HEAD:   pre {background-color: #111; color: #ccc;}
+#+HTML_HEAD: </style>
+
+* General
++ DISCLAIMER: I DO ELECTRONICS AND 3D DESIGN SOLELY AS A HOBBY. THERE
+  COULD BE ERRORS THAT CAN RESULT IN ALL KINDS OF DAMAGE. USE THESE
+  DESIGNS AT YOUR OWN RISK.
+
++ This design is released under Creative Commons Zero (CC0) license.
+
++ Authors:
+  - Svjatoslav Agejenko
+    - Homepage: https://svjatoslav.eu
+    - Email: [[mailto://svjatoslav@svjatoslav.eu][svjatoslav@svjatoslav.eu]]
+
+  - Valeria Agejenko
+
++ See also:
+  - [[../../index.html][Other physical projects in this repository]]
+  - [[https://www.svjatoslav.eu/projects/][Other projects hosted at svjatoslav.eu]]
+
+* Project description
+End-result looks like this:
+
+[[file:make.png]]
+
+It all started with couple of cheap USB desk fans that were a bit too
+noisy:
+
+[[file:mini%20fan.png]]
+
+Idea is to add DC-DC step-down converter to reduce motor voltage to
+make it quieter ([[https://www.amazon.de/gp/product/B07K3W78SQ/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1][Purchased form here]]). And since I already have this
+USB powered thing on my desk, why not to share this power to allow
+charging of various other USB powered devices.
+
+I ended up with this schematic:
+[[file:schematic.png]]
+
+USB power of 5 volts that enters the system via DC jack is distributed
+to two USB-A connectors on the front panel. Note: USB data is not
+connected. Therefore this hub is for power sharing only.
+
+DC-DC fly-back converter could introduce voltage ripple in the
+system. To smooth it out, there is capacitor (C1) and inductor (L1).
+
+Step-down voltage converter has adjustable output voltage. So after
+assembling, it can be tuned with screw-driver to reach desired
+noise/airflow tradeoff.
+
+From original fan I only kept the engine and blades. Engine is
+attached with screws to following back-plate:
+
+[[file:fan%20housing%20-%20fan%20mount.png]]
+
+And result is encased into pipelike case:
+
+[[file:fan%20housing%20-%20cover%20assembly.png]]
+
+
+Download:
++ STL: [[file:fan%20housing%20-%20fan%20mount.stl][fan mount back plate]]
++ STL: [[file:fan%20housing%20-%20cover.stl][pipe-like case]]
++ [[file:fan%20housing.FCStd][FreeCAD project]]
+
+Fan enclosure attaches to the rectangular body below using following
+connector (glued to the fan housing):
+
+[[file:fan%20housing%20connector.png]]
+
+Download:
++ [[file:fan%20housing%20connector.stl][STL file]]
++ [[file:fan%20housing%20connector.FCStd][FreeCAD project]]
+
+Bottom part to house 2 PCBs, on/off button and DC connector:
+[[file:bottom%20stand%20body.png]]
+
+Component attachment:
+[[file:make,%202.png]]
+
+And is closed by cover:
+[[file:bottom%20stand%20cover%20assembly.png]]
+
+Download:
++ STL: [[file:bottom%20stand%20body.stl][bottom stand body]]
++ STL: [[file:bottom%20stand%20cover.stl]]
++ [[file:bottom%20stand.FCStd][FreeCAD project]]
+
+After assembly, it looks like this from the back:
+[[file:make,%203.png]]
+
+Note, part of the body is deformed during printing. I have heated bed
+and I even printed raft support in Cura and it did not help. In my
+experience black PLA filament is awful in comparison to transparent
+one. Has inferior flow (results in slower print speed) and tends to
+deform easily. Will never buy it again.
+
+Fan top and bottom halves are attached using [[https://www.amazon.de/gp/product/B00OOLKD2G/ref=ppx_yo_dt_b_asin_image_o00_s00?ie=UTF8&psc=1][camera tripod quick
+release screw]].