nes_pi
Posts: 20
Joined: Mon Jun 25, 2018 1:35 am

Pi Fan not working

Sun Jul 22, 2018 7:01 am

I followed this guide exactly:

https://github.com/KyleRoss/rpi-fan-controller

But nothing happens and no fan spins when i run sudo rpifan. I have checked that all connections are good with a multimeter. What could be wrong?

One thing I noticed is the default pin is 18 but pin 18 is not hooked up. I tried pin 12 too and still nothing happened. I am using a pi 3b+.

DirkS
Posts: 10130
Joined: Tue Jun 19, 2012 9:46 pm
Location: Essex, UK

Re: Pi Fan not working

Sun Jul 22, 2018 7:36 am

nes_pi wrote:
Sun Jul 22, 2018 7:01 am
One thing I noticed is the default pin is 18 but pin 18 is not hooked up. I tried pin 12 too and still nothing happened. I am using a pi 3b+.
Had a quick look at the code and it seems to use BCM numbering. So that should be GPIO18, physical pin 12
The code seems to switch on / off the fan depending on CPU temperature.
Are you sure it is high enough to trigger it?

See https://github.com/KyleRoss/rpi-fan-con ... #cli-usage for command line arguments.


BTW: I don't think you need to use sudo, ty running the script without it

nes_pi
Posts: 20
Joined: Mon Jun 25, 2018 1:35 am

Re: Pi Fan not working

Sun Jul 22, 2018 10:11 pm

DirkS wrote:
Sun Jul 22, 2018 7:36 am
nes_pi wrote:
Sun Jul 22, 2018 7:01 am
One thing I noticed is the default pin is 18 but pin 18 is not hooked up. I tried pin 12 too and still nothing happened. I am using a pi 3b+.
Had a quick look at the code and it seems to use BCM numbering. So that should be GPIO18, physical pin 12
The code seems to switch on / off the fan depending on CPU temperature.
Are you sure it is high enough to trigger it?

See https://github.com/KyleRoss/rpi-fan-con ... #cli-usage for command line arguments.


BTW: I don't think you need to use sudo, ty running the script without it
I appreciate your reply and looking into this very much, DirkS.

My Pi 3B+ gets to 55-56 degrees and stays there by the time i'm done booting into Raspbian, so i fire up the fan controller and it says it's going to turn on the fan but the fan never starts moving. I think i should double-check my hardware work.

I've also found someone claiming on Stackexchange that in most of these pi fan examples, the guides have the transistor facing backwards thus not making a useful circuit. I will have to double check this as well
Hello and welcome. Note that circuit has a major drawback: the transistor on the high-side (near + voltage with respect to the load) is not a useful circuit with an NPN transistor. It is unfortunately somewhat viral and often-posted but still wrong. Connect the emitter (the arrow) to ground and put the load (fan) between collector and +5V. See raspberrypi.stackexchange.com/a/28201/19949 – Ghanima♦ Aug 5 '17 at 10:53

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Imperf3kt
Posts: 3232
Joined: Tue Jun 20, 2017 12:16 am
Location: Australia

Re: Pi Fan not working

Sun Jul 22, 2018 10:21 pm

I use this when I need a fan on my Pi
viewtopic.php?f=91&t=186439&p=1177096#p1179477

Works like a treat.
55:55:44:44:4C
52:4C:52:42:41

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davidcoton
Posts: 4541
Joined: Mon Sep 01, 2014 2:37 pm
Location: Cambridge, UK

Re: Pi Fan not working

Sun Jul 22, 2018 11:40 pm

nes_pi wrote:
Sun Jul 22, 2018 7:01 am
I followed this guide exactly:
https://github.com/KyleRoss/rpi-fan-controller
Ditch that guide, at least the hardware part. The author has numbered the Pi pins wrongly, can't be bothered to identify the transistor connections, and doesn't know how to put together a working circuit.
The circuit is a low-side driver, it needs a resistor in the GPIO to base connection or the transistor and the Pi are both at risk.
Replace the link between Pi pin 12 and transistor base with a 3K3 resistor and all should be well -- except if you tried the circuit as it stands you may need a new transistor and, worst case, a new Pi.
Signature retired

nes_pi
Posts: 20
Joined: Mon Jun 25, 2018 1:35 am

Re: Pi Fan not working

Mon Jul 23, 2018 12:27 am

davidcoton wrote:
Sun Jul 22, 2018 11:40 pm
nes_pi wrote:
Sun Jul 22, 2018 7:01 am
I followed this guide exactly:
https://github.com/KyleRoss/rpi-fan-controller
Ditch that guide, at least the hardware part. The author has numbered the Pi pins wrongly, can't be bothered to identify the transistor connections, and doesn't know how to put together a working circuit.
The circuit is a low-side driver, it needs a resistor in the GPIO to base connection or the transistor and the Pi are both at risk.
Replace the link between Pi pin 12 and transistor base with a 3K3 resistor and all should be well -- except if you tried the circuit as it stands you may need a new transistor and, worst case, a new Pi.
Thanks a bunch! I have more transistors so that is no big deal.

I did put a 1n4001 diode between the transistor and 5v pin to protect the Pi, but i did not use a resistor.

My pi is still working ..... so far :lol:

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