ideas for a project

[robs24]

Hello, I have a project in mind but I don't quite know how to go about making it happen. I have a very small fan that I need to continuously turn on and off, for a Halloween thing. I am not the most experienced in electronic projects. I am hoping somebody could point me in the right direction on how to go about this.

[hamster_nz]

One man's very small fan is different to another... a common small fan is 25mm x 25mm x 7mm, and runs from 12V DC. Any chance of more info on the fan?

How often and how long does the fan need to be switched off and on? Every second? Every hour?

[robs24]

Sorry about that, but yes something similar to the 25x7x7 fan. I would like to have it turn on and off every few seconds.

[RJFreeman]

I am hoping somebody could point me in the right direction on how to go about this.

555 timer

[RJFreeman]

I would expect this sort of thing would probably do the trick:

http://www.vellemanusa.com/products/view/?id=350686

Manual here
http://www.vellemanusa.com/downloads/0/minikits/manuals/manual_mk111.pdf

On time adjustable between 0.5 and 5 seconds, off time between 2.5 and 50 seconds (or vice versa, depending on how you wire up the relay) will hopefully cover your desired "few seconds", although you could also increase the value of trimpot RV2 if you wanted to increase the on time.

[obiwanjacobi]

I am hoping somebody could point me in the right direction on how to go about this.

555 timer

... and a transistor/mosfet to witch the 12V fan.

A couple of resistors and caps and you're all set.

To give you an idea (from interweb):


R2, R3 and C1 dictate the speed/time at which the output is on and off.

You (probably) cannot drive the fan directly from the output. That is where the transistor comes in.