How to control computer fans with Arduino UNO + vvvv (Firmata)

Hi guys!

First of all you are avvvvesome and sorry for my late response. My new Arduino got delivered today (Yes, I already destroyed two UNOs, hehe).

The ULN2003A is a blast and works super good. Fan 1 and 2 are easy to control with vvvv. Finally I am very close to my goal. So thanks again for your help. As I mentioned I would like to provide a tutorial as a contribution for you.

But there are some issues, I would like to ask you:

The Setup:

https://vvvv.org/sites/default/files/imagecache/large/images/Schaltplan.png

https://vvvv.org/sites/default/files/imagecache/large/images/Setup_ULN2003A.jpg

Status quo (Video):

– Fan 1 and 2 work perfectly.
– Fan 3 and 4 don’t work.
– Using 1x or 2x ULN2003A lets move just Fan 1 and 2.
– The Setup is very noisy. Wierd sounds! Especially from Fan 4.How can I avoid them?
– Here: Electrical source is the Vin Pin of the Arduino UNO with an 12 Volt external Power Supply.

My questions to you:

  • How can I avoid the noises? Using resistors? I have used 220Ohms, but it didn’t work.
  • Maybe it is better to connect the setup to a 12 Volt Power Supply?
  • Is the Setup correct? Or can you provide me a better one. This would be perfect.

Chers and thanks again
markusch