DIY Inline Fan Speed Control

[mcduffiem]

Someone had asked me to draw up the wiring for a inline fan speed controller based on a DP3T slide switch that supplied 12V, 7V and 5V. The adantage to not using resistors or diodes to reduce voltage is that no additional heat is produced. And yes my MS Paint skills are horrible.

 

[mcduffiem]

Actually I wanted this to appear inline:

 

[DanFraser]

Thats a good idea! Once i get really modding stuff, i'll remember that! lets see what happens from testing a other things...

 

[Fraggle]

SWEEET!!!

I've been wondering how the heck to do that. great diagram, I'm gonna run to radio shack!!

How many fans would you run off that? and would it be possible to add an LED ? or 3? or one that does 3 colors (haven't found that yet)

Fraggle

 

[mcduffiem]

The switch was a Maplin item, but Rad Shack, DigiKey, Jameco, et al, all have similiar parts.

As for the number of fans you could run, I have no amperage (current) rating for this device. In general terms you would need to add the current draw of the total number of fans and make sure the switch could hand it. Digikey has a 11A part for ~$1 that would handle almost any number of fans you care to throw at . I'm sure oher vendors have similiar parts.

You need to ensure the proper voltage to the LED, 5V, 3V, etc. WHat exactly were you looking to do?

 

[Fraggle]

I'd like to have a "speed indicator" of some kind.......preferably lighted.

Mostly I'm just gathering information, as I'm not sure what my system will end up looking like. first I have to start getting temps I like, at an acceptable ambient, with an acceptable noise level.



Cheers


Fraggle

 

[ocean]

That's really nice work!
Is that basically 7volt fan mod?
You are using the 5volt line as a return for the 12volt line?
The only reason I ask is that I've read that the 7volt mod is "bad electronics".
A nice neat solution like your's though is very tempting. The pot on my radiator fan gets rather hot when I slow it down.

 

[mcduffiem]

Yes it just an implementation of the 7V mod. I had soemone at another board ask for a DIY implementation of

It obviously uses some form of volatge regulation since it only has (presumably) 12V connections. I pointed out that a simple DP3T switch (preferably slide for this implementation) would suffice to supply 12, 7 and 5V and not generate additional heat.

The crude picture was generated when a simplier explanantion was requested.[