1 Topic by Diecrusher

  • Diecrusher
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Topic: Sanguino 12v power question for electronics gurus

I am tapping 12v off of my sanguino board to power the filament cooling fan hooked to the extruder.

I would like to make the fan variable speed so I thought that it would just a pot to it as I have tried this on the fan when hooked to a 12vdc wall wart and it works fine..... but then I thought maybe this could damaged the sanguino board by resisting the voltage coming off of the board and may damaged something in the circuitry. 

Opinions??

Thanks,
Tim

2 Reply by danny

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Re: Sanguino 12v power question for electronics gurus

I can't see that there should be any problems with this.

3 Reply by Bad Coffee

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Re: Sanguino 12v power question for electronics gurus

If you put the pot between the board and the fan you should be fine.  I can't see how the change in voltage would bother the board. 

You do have to take into account the amperage that the potentiometer adds to the circuit.  So if the board says the pins are 12vdc @200ma, you can't put a 200ma fan AND a pot on the output, because the pot adds resistance (and therefore amerage) to the circuit.  You'd need a 150ma fan and the pot to turn down the fan.  Most of the small fans (and even the bigger ones) use less than 500ma. Check the specs on the fan before you hook it up.

B

4 Reply by Diecrusher

  • Diecrusher
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Re: Sanguino 12v power question for electronics gurus

Does any one know the max. current draw off of these 12v pins on the Sanguino? 

I've read suggestions elsewhere that the proper way to power a brushless DC motor, in this case a fan, is with a power transitor/diode arrangement on PWM pins on the board and an external capable power supply.

Opinions?

5 Reply by Bad Coffee

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Re: Sanguino 12v power question for electronics gurus

Proper?  Sure.  Practical?  Eh, not so much.

If you're looking to get very precise CFM measurements for a specific temperature to ensure absolutely perfect extrusion, you should hook it up through the PWM.

Since it's just the extruder fan, just wire it up for on/off.

B

6 Reply by solijohn

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Re: Sanguino 12v power question for electronics gurus

Bad Coffee wrote:

Proper?  Sure.  Practical?  Eh, not so much.

If you're looking to get very precise CFM measurements for a specific temperature to ensure absolutely perfect extrusion, you should hook it up through the PWM.

Since it's just the extruder fan, just wire it up for on/off.

B

As I recall, there is a way to control the fan via G-code.

Former Solidoodle employee, no longer associated with the company.