[mythtv-users] Quiet fans

Yan Seiner yan at seiner.com
Mon Oct 20 11:42:41 UTC 2008


Peter Loron wrote:
> On Oct 17, 2008, at 1:41 PM, Yan Seiner wrote:
>
>   
>> On Fri, October 17, 2008 1:10 pm, Peter Loron wrote:
>>
>>     
>>> Oh, yeah. I just checked my inventory, and I've got temp sensors from
>>> Dallas/Maxim. Analog, and ST Micro in the parts bin. Guess my only
>>> excuse for not doing it now is lack of time.  :-)
>>>
>>> Having the sensor on leads would be nice for checking the temp
>>> someplace the PCB won't fit. Should also be pretty easy to multiplex
>>> some sensors if you wanted multiple readings.
>>>       
>> You know, if you were to build a few of these, I'd buy a couple or  
>> three.
>> Basically, something that can handle 2-3 temp sensors, run up to 4  
>> fans,
>> and works off a regular PC power supply.
>>
>> That way you could stick the temp sensors inside the raid array and  
>> run
>> the fans based on the max temp in the array.
>>
>> (and a LCD showing the temp, usb interface, drivers... :-)  Just  
>> kidding
>> on those.)
>>     
>
> I've been tinkering with parts and spreadsheets. Looks like my cost  
> (in prototype quantities) for a unit that will programmatically  
> control 3 fans (via PWM), have 3 thermistors controlling them, and  
> have a 2x20 LCD screen, and USB connectivity would be around $26.
>
> A "dumb" controller with direct temp controlled PWM driven fan headers  
> and 3 thermistors would be around $13. No microcontroller, no USB, no  
> display.
>
> The fancy controller would have some kind of software that would allow  
> you to monitor the status of the fans, adjust the speed<-->temp ratio,  
> etc. The display would also have some programmability.
>
> Thoughts? How much would *YOU* pay?  :-)
>
> Basically if I can determine there is a market worth my time, I'll see  
> what I can do.
>
>   
HI Peter:

Thanks for looking into this.  A couple of questions:

One of my cases has 1 group of 2 60mm fans, and 1 group of 2 80mm fans, 
a total of 4 fans.  The other has 1 group of 2 60mm fans and 1 group of 
5 60mm fans, a total of 7 fans.  Would there be enough current to drive 
2-3 fans from one connection or would I need to drive each fan separately?

For the programmatically controlled unit, would the cost drop 
significantly if the LCD was dropped?

Anyway, given your prices, you would probably be looking at having to 
sell these at $50 and $25 to make it worthwhile.  I'd be in for one of 
each or maybe 2 of the programmable ones if I can use 1 per case.

--Yan



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