misc/USB desk fan mod/index.org

   1 #+TITLE: USB desk fan modification
   2 #+author: Svjatoslav Agejenko
   3 #+LANGUAGE: en
   4
   5 * (document settings) :noexport:
   6 ** use dark style for TWBS-HTML exporter
   7 #+HTML_HEAD: <link href="https://bootswatch.com/3/darkly/bootstrap.min.css" rel="stylesheet">
   8 #+HTML_HEAD: <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
   9 #+HTML_HEAD: <script src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.5/js/bootstrap.min.js"></script>
  10 #+HTML_HEAD: <style type="text/css">
  11 #+HTML_HEAD:   footer {background-color: #111 !important;}
  12 #+HTML_HEAD:   pre {background-color: #111; color: #ccc;}
  13 #+HTML_HEAD: </style>
  14
  15 * General
  16 + DISCLAIMER: I DO ELECTRONICS AND 3D DESIGN SOLELY AS A HOBBY. THERE
  17   COULD BE ERRORS THAT CAN RESULT IN ALL KINDS OF DAMAGE. USE THESE
  18   DESIGNS AT YOUR OWN RISK.
  19
  20 + This design is released under Creative Commons Zero (CC0) license.
  21
  22 + Authors:
  23   - Svjatoslav Agejenko
  24     - Homepage: https://svjatoslav.eu
  25     - Email: [[mailto://svjatoslav@svjatoslav.eu][svjatoslav@svjatoslav.eu]]
  26
  27   - Valeria Agejenko
  28
  29 + See also:
  30   - [[../../index.html][Other physical projects in this repository]]
  31   - [[https://www.svjatoslav.eu/projects/][Other projects hosted at svjatoslav.eu]]
  32
  33 * Project description
  34 End-result looks like this:
  35
  36 [[file:make.png]]
  37
  38 It all started with couple of cheap USB desk fans that were a bit too
  39 noisy:
  40
  41 [[file:mini%20fan.png]]
  42
  43 Idea is to add DC-DC step-down converter to reduce motor voltage to
  44 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
  45 USB powered thing on my desk, why not to share this power to allow
  46 charging of various other USB powered devices.
  47
  48 I ended up with this schematic:
  49 [[file:schematic.png]]
  50
  51 USB power of 5 volts that enters the system via DC jack is distributed
  52 to two USB-A connectors on the front panel. Note: USB data is not
  53 connected. Therefore this hub is for power sharing only.
  54
  55 DC-DC fly-back converter could introduce voltage ripple in the
  56 system. To smooth it out, there is capacitor (C1) and inductor (L1).
  57
  58 Step-down voltage converter has adjustable output voltage. So after
  59 assembling, it can be tuned with screw-driver to reach desired
  60 noise/airflow tradeoff.
  61
  62 From original fan I kept:
  63 + engine
  64 + blades
  65 + DC jack
  66 + on/off swith
  67
  68 Engine is attached with screws to following back-plate:
  69
  70 [[file:fan%20housing%20-%20fan%20mount.png]]
  71
  72 And result is encased into pipelike case:
  73
  74 [[file:fan%20housing%20-%20cover%20assembly.png]]
  75
  76
  77 Download:
  78 + STL: [[file:fan%20housing%20-%20fan%20mount.stl][fan mount back plate]]
  79 + STL: [[file:fan%20housing%20-%20cover.stl][pipe-like case]]
  80 + [[file:fan%20housing.FCStd][FreeCAD project]]
  81
  82 Fan enclosure attaches to the rectangular body below using following
  83 connector (glued to the fan housing):
  84
  85 [[file:fan%20housing%20connector.png]]
  86
  87 Download:
  88 + [[file:fan%20housing%20connector.stl][STL file]]
  89 + [[file:fan%20housing%20connector.FCStd][FreeCAD project]]
  90
  91 Bottom part to house 2 PCBs, on/off button and DC connector:
  92 [[file:bottom%20stand%20body.png]]
  93
  94 Component attachment:
  95 [[file:make,%202.png]]
  96
  97 And is closed by cover:
  98 [[file:bottom%20stand%20cover%20assembly.png]]
  99
 100 Download:
 101 + STL: [[file:bottom%20stand%20body.stl][bottom stand body]]
 102 + STL: [[file:bottom%20stand%20cover.stl]]
 103 + [[file:bottom%20stand.FCStd][FreeCAD project]]
 104
 105 After assembly, it looks like this from the back:
 106 [[file:make,%203.png]]
 107
 108 Note, part of the body is deformed during printing. I have heated bed
 109 and I even printed raft support in Cura and it did not help. In my
 110 experience black PLA filament is awful in comparison to transparent
 111 one. Has inferior flow (results in slower print speed) and tends to
 112 deform easily. Will never buy it again.
 113
 114 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
 115 release screw]].