Controlling 12VDC fan using digital output on DAQ 1

[showcaser]

Hello

Here is the situation. I have a DAQ, 12volt DC fan, and a 12 volt battery. Does anyone have an idea of how I could hook up the fan, battery and DAQ so that I could use one of the digital output ports on the DAQ to turn the fan on and off?

The fan is of course powered by the battery but my interest is in having the software (through the DAQ) control the fan’s on/off state instead of manually using a physical switch. What kind of circuit might allow me to accomplish this?

Any advice would be much appreciated.

Showcaser

 

[IRstuff]

A 5V relay would probably be the simplest solution.

TTFN

 

[erwick]

The simplest and cheapest way to do this is using a N-channel MOSFET. Drive the gate with the output of the DAC (Digital to Analog Converter).Try a search on IRFL019 check the current going through the fan though.

 

[IRstuff]

Only if you're willing to electrically connect the fan and battery to the DAC ground.

TTFN

 

[llrelease]

If your DAQ card has a general purpose counter output, you could use it to drive a mosfet and vary the fan speed by varying the duty cycle of the counter output. If you only need on/off control, you could use a 5V digital output to drive a transistor. I have used both of these approaches with success.

llrelease

 

[kkoorndyk]

I would go with a Relay or an optoisolator

Kris

 

[automatic2]

Use your DAC output as feedback into a PWM driver. You'll likely need to buffer it's output, but then you can translate variable speed if you need. Otherwise it's FF or 00.

 

[47gandalf]

The market for laptop PCs has led to manufacturers' creating special ICs for this exact function (controlling a DC fan motor). Take a look at web sites for people like MICREL or Texas Instruments or others who make PWM chips. Because the volumes are large in PC land, the parts are cheap even for those of us who won't be buying more than one.