Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: adaboy on November 12, 2011, 12:01:21 AM

Title: getting to know heat sinks and domes
Post by: adaboy on November 12, 2011, 12:01:21 AM
Hi, though not particularly new to most any one sphere involved in robotics (via hobbies and work) I've never let them culminate
into a robot until now, or that is to say hopefully soon (gods willing, creeks don't rise and such).
Things are going nicely with the routine microcontroller experiments getting acquainted to what's common, procuring dc motors with encoders,
playing with sensors and the like. Speaking of spheres, I'm stoked to have received a fantastic 12" hemisphere in acrylic for an unbeatable price
and was very happy when I received it regarding clarity and relative flawlessness, but this being my first post I don't want to come off
plugging someone or seeming spammish. $44 bucks after shippinf and almost as nice as underwater viewing, though. VERY pleased.
It will be a dome on top of a 6 wheeler so one can see the "brains" and all the nice, wee LED's that are so common all over boards these
days that actually reflect circuits active (and here I thought sci-fi flashing lights behind open spaceship panels would never be for anything but
Scavenging motors from printers is great (going more with the regular ones with encoders vs. steppers more since I don't make my own
motor drivers and it cuts h-bridge shields etc. in half $$).
Three of the larger, higher-wattage dual motor driver shields come without heat sinks yet attached but are bare, vertically waiting for such
with rows of 4 on each side with holes begging to be screwed onto aluminum fins.
I had an old, red-anodized CB amp. whose chassis was a big heat sink, so I"ve sawed it on the tile saw into pieces trying to milk
 it for enough so I'll start posting pics ASAP.
One concern will be trapping heat inside the dome, so I'll need plenty of ventilation. I sought wee fans out of a scrap laptop but they were
too idiosycncratically part anc parcel of the whole assembly I couldn't transplant them effectively, so I"ll be looking around for more regular,
self-contained fans like in desktop pc's but at most half that typical size...?
Love the site all!

Title: Re: getting to know heat sinks and domes
Post by: eTag on November 12, 2011, 12:37:52 AM
one sugestion for fans (if you haven't found any) is takes a couple of weeks to get there...but i found some decent micro fans on there for about $1-3 good quality and multiple voltage ratings...
Title: Re: getting to know heat sinks and domes
Post by: Fr0stAngel on November 13, 2011, 10:09:11 PM
A couple of pictures of your project would be nice. It would give a much clear idea about the dimensions and design complexity...
In any case, i wouldn't count on using fans for under-water cooling. If you attach them inside the dome, they would just add more overall heating effect.
Title: Re: getting to know heat sinks and domes
Post by: adaboy on November 23, 2011, 02:13:35 AM
this is a sample or trial layout for most of the items to be secured onto the circular microcontroller,
motor driver, etc. board that will be visible under the dome (not including some additional "shields"
that will be stacked over the one in the middle there).
It's not intended to go under water (as cool as that would be), I was just impressed enough with the dome
being of almost that kind of undistorted clarity for such a reasonable price..
I will be cutting away some underlying yellow/green board material (used to be a high-vis archery polo shirt of mine before
the glass and resin haha) to provide ventilation, as structural integrity allows in between the pcb's.
It wasn't perfectly logical to have some of the heat sinks to not be aligned vertically, but I'm trying to have this project
move along suitably and that's how much or what I had; it didn't fit and/or line up no matter what I did so I turned them
90 deg. and suddenly I had just enough aluminum fins to fit, some shorter I can act like was because of the arc of the dome, lol.
Some of the wasted-looking vertical space will be filled with the additional shields stacked onto the Arduino and the top one will be
a UART WiFi module with a wee antenna poking up in the center nearly reaching the apex. I could fit it externally but I'd have
to send off for an antenna cable patch and for all I know there'd be loss (?)..
...but so yeah it just seems nice to me to get some ventillation in there since I'm on dry land, and esp. with what I've done with the horizontal
red anodized sink fins. I've got few couple more randomly scavenged scrap electronics to pull apart to see if I can cannibalize a wee
high performance fan or two that are maybe 1/3 the size of the once that cool my PC tower, for example.