Chamber fan stops temperature sensors [Solved]

rjpassaro · March 10, 2016, 6:48pm

Hi,
This is my first post. I have an Antec TriCool fan and I retrofitted it with a rj11 connector. When I plug the fan into the brewpi the fan turns on and my temperature sensors stop working. If I unplug the fan, the sensors start working again. Is this because the fan is 12v and the temp sensors are 5v? I have a brew pi spark v2 and am in test mode.

sunadmn · March 10, 2016, 7:26pm

I don’t believe those are to be used to direct power anything like a fan and you may end up breaking things.

Cheers,
-Stephen

rjpassaro · March 10, 2016, 7:29pm

How should I power the fan then? Should I use another SSR?

-Ronnie

Elco · March 10, 2016, 10:22pm

It would really help if you tell us what kind of fan you are using.

How much current does it draw?
Does it have a PWM input (internal transistor)?
How did you connect it to the RJ11 connector?

SSRs are not very suitable to switch DC current. A simple transistor is better for that. But does the fan really need to be switched?

rjpassaro · March 10, 2016, 10:37pm

The fan I’m using is an Antec TriCool 120mm DBB Cooling Fan with 3-Speed Switch. I’m not sure how much current it draws but the Input Voltage is 12V DC. I’m also not sure if it has PWM input. It’s 3-pin so I connected it to 12V, GND, and OneWire on the RJ11 connector. I want to fan to continually run so it doesn’t need to be switched.

-Ronnie

Elco · March 11, 2016, 12:04am

You didn’t know what the 3rd pin did, so you just connected it to OneWire?

No wonder it is taking down your OneWire communication.

Please disconnect it ASAP and only connect the data pin of OneWire devices to the OneWire pin of the controller. Things like this can easily damage electronics.

rjpassaro · March 11, 2016, 12:20am

Thanks for the help! Do you have any suggestions on that the third pin is?

Elco · March 11, 2016, 12:26am

Probably a pulsed feedback pin to detect the fan speed.

(What you did is equivalent to plugging a fan wire in a sata port on a motherboard, because you don’t know where else it needs to go. Please ask if unsure.)

rjpassaro · March 11, 2016, 1:30am

Is it possible to use a RJ11 connector to power the fan? Do you think it is ok to just use the 12V and GND and not use the third wire?

Elco · March 11, 2016, 11:15am

Probably, it depends on how much current the fan draws.

But powering it separately is less risky. If you do have another 12V supply, I would just power it separately from BrewPi.