[mythtv-users] Quiet fans

[Peter Loron]

On Oct 21, 2008, at 6:40 AM, Mike Perkins wrote:

> As someone who got his first soldering iron at age 11, I have been  
> following
> this thread with some interest. Although I have nothing currently to  
> contribute
> to the manufacture, schematics, etc. aspects of your projects, I do  
> have some
> design/implementation questions.
>
> If you are planning on using external sensors, rather than the ones  
> on the
> motherboard, where do you expect to site them? I would naturally  
> expect them to
> be somewhere near the items being monitored. If so, then there will  
> be a certain
> level of decoupling from the fans which you are controlling, given  
> that most
> fans are in the front, back or occasionally sides of the case, and  
> not next to
> the items being cooled. How do you plan to handle the feedback  
> delay? And how do
> you determine that the big fan you screwed into the back of the box  
> is,
> actually, contributing to the cooling of the particular component  
> you are
> monitoring? Airflow is not an exact science, after all[1].
>
> These questions are not intended as criticisms, rather just to  
> satisfy my curiosity.
>
> -- 
>
> Mike Perkins
>
> [1] Aeronautical engineeers may disagree; however, just try flying  
> your F-16
> around the inside of my server!
>

The idea (at least for me) is to be able to combine your fans and  
sensors in whatever grouping you want. In some situations, I suspect  
that adjusting fan speeds will have a noticeable impact on  
temperatures in specific locations. In others, as you say, not so  
much. That right there is valuable information if you are fiddling  
with your case and hardware arrangements, trying to optimize airflow,  
etc.

Somebody in the "investigation" phase might simply use the sensors and  
LCD (or software) as a probe to measure temps in various situations,  
leaving the fans on a specific static speed.

I've got some parts on order, more fiddling to be done on the  
breadboard...

-Pete