PWM fan for Retroflag NESpi+

tacodog

So, I received my chip from mini mod today, and I installed it. Here is my experience.

For this review, keep in mind that I am using a fan that came bundled with the NESPi case on amazon. I think a lot of my problems are due to the fan and not this chip.
https://www.amazon.com/Retroflag-Functional-Shutdown-Heatsinks-Raspberry/dp/B07872ZDCS/

First of all, it does what it claims. The chip seems to work as described and does control the fan speed. I can adjust the speed with python commands, and it is compatible with the many pre-made python scripts available.
My fan connection didn't fit into the plug on the chip. Not the fault of the chip maker, I think this fan has a nonstandard connection. To made the connection, I had to remove the pins from the connection bracket, wrap each one in electrical tape, and push them on to the pins directly.
There is an (in my opinion) unnecessarily bright LED on this chip. As in, I'm still seeing spots a half hour after installing it. The light shines through the slats in the top of the NESPi case, and ultimately I ended up covering it in electrical tape just so I could look at it.
The device does not attach to the power pins tightly. The instructions say to bend one of the pins to hold it in place, but I wasn't comfortable doing that. Right now I have a wadded up piece of paper underneath the chip, holding it against the pins with tension. Seems very "Mickey Mouse" to me, and I will probably end up soldering it in place once I'm happy with everything. In fact, I would say, soldering should be considered necessary for anyone considering this chip.
At any dutycycle less than 100, my fan makes a super annoying mosquito noise, getting louder and louder down to 30% where the fan stops completely (but still making noise). Again, I am more inclined to blame the fan for this than the chip. If anyone can suggest a fan that is known to work with a PWM, please let me know and I will try swapping out that fan for mine.

Silent

@tacodog Thanks for those! It's actually somewhat worrying, since I have the same fan for MegaPi case... I'm especially uncomfortable with the soldering part. I hope I can get rid of duty cycle artifacts somehow, maybe by changing the frequency PWM operates at.

I may still go for it though, glad to hear the chip works fine. I just hope it's not going to be wasted $30.

EDIT:
On a second thought, I am not convinced anymore it's worth it considering I also have this weird, noisy fan. I will likely encounter the same issues as you...

cyperghost

@Silent @tacodog use 2 si-diodes these drop the current to 3.6V and your fan is quiet. I think most fans run out of the box with just 3V

Silent

@cyperghost Call be lazy/incompetent but I'm interested in this PCB solely because I don't want to do any soldering on my own. While your solution is valid, it defeats the purpose of me getting this PCB.

Silent

@tacodog I asked mini-mods about what fan they are using for tests (because it's safe to assume it fits and sounds fine) and that's the response I received:

During all the development of this board, I have use a GDT 2Pin 5V 0.2A

30x30x7mm Fan (see attached picture) I have purchase this fan from ebay

awhile back and is the one I have used for all my test.

Looks like finding this specific fan may be hard (at least the ones shipping to Europe) =(

EDIT:
Looks like this is the same fan:
https://www.ebay.co.uk/itm/5V-mini-3cm-30mm-30x30x7mm-Brushless-Cooling-Cooler-Fan-DuPont-Connector-3007S/262986426654?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D20160323102634%26meid%3D3e0068012e1a44f9bbf3e5766d39a5ba%26pid%3D100623%26rk%3D3%26rkt%3D6%26sd%3D122949264413%26itm%3D262986426654&_trksid=p2047675.c100623.m-1

EDIT2:
One more question - does the fan also whine when you turn it off completely with 0 duty cycle? If it does not then I can still go for it and just make it a toggle, without several speed steps I guess... and maybe upgrade later along the way.

tacodog

@Silent There is no noise when the fan is off. And the board and scripts can be used as intended to turn on and off the fan. It might just be my ears, but I hear a high pitched sound even at full speed on the fan. This is true with or without the PWM.

My hope with getting this was that it would reduce the fan speed and thus the noise, but in my case, it seems to make it worse. If you don't hear anything, you should be fine using it as an on/off switch.

Silent

@tacodog said in PWM fan for Retroflag NESpi+:

@Silent There is no noise when the fan is off. And the board and scripts can be used as intended to turn on and off the fan. It might just be my ears, but I hear a high pitched sound even at full speed on the fan. This is true with or without the PWM.

My hope with getting this was that it would reduce the fan speed and thus the noise, but in my case, it seems to make it worse. If you don't hear anything, you should be fine using it as an on/off switch.

Yes, the fan does sound annoying, but maybe I should try on my own - as clearly it's very subjective. So the only remaining hurdle is having to mess up fan's connector, but since this fan is worth probably less than $2 it's not a big deal.

Even in the worst case on/off without speed control is going to be far, far better than annoying always on I have right now - as with fan as annoyingly noisy as this one watching movies with Pi running is a tad frustrating.

Thanks for the insight! I'll bite the bullet and order this PCB next week then pray I'm not going to be screwed over by customs and duty fees.

Silent

Also, have you tried manipulating frequency instead of duty cycle? Technically it should give same results (same average voltage), but worth a try.

tacodog

@Silent yeah I tried a handful of different frequencies between 30 and 120. It just seemed to change the pitch of the humming.

Silent

@tacodog Sounds about right then. That's how this fan sounds initially before it's spinning at full speed.

Based on all this I think I will buy the PCB and then in the future upgrade my fan to this:
https://www.ebay.co.uk/itm/5V-mini-3cm-30mm-30x30x7mm-Brushless-Cooling-Cooler-Fan-DuPont-Connector-3007S/262986426654
as it's the same fan as the one mini-mods is using in their guides.

Silent

So I ordered the Fan Control - fingers crossed it's going to work fine with the fan I have right now! I intend to upgrade to this GDT fan in the future.

Once it arrives (it may take a few weeks) I'll also share my thoughts on this little device.

Silent

Hey,

my Fan Control PCB has arrived and I successfully installed it in my MegaPi. I love how quiet (Silent? =) ) my pi is now!

I observed exactly the same issues as you, too - which makes perfect sense, given the fact we seem to have the same fans. Not a big issue for me though, I will be more than happy with just an on/off script!

Also the LED is very bright indeed, but it doesn't shine through the case - I can only see it when I open the SD card storage, which to me is a plus (can debug it visually).

Thank you for making me aware of this PCB! It took a very long time to arrive but I am very happy with it, as honestly the buzzing was kinda bothering me when playing GameBoy games or watching movies.

EDIT:
I am therefore joining the question - does anybody know a fan which would play nice with PWM regulation? This one definitely doesn't like it.