Help making simple PWM booster for fan - Page 1
Forum section: electronics / beginners

author: leham
author_rank: Regular Contributor
timestamp: September 12, 2015, 07:24:56 am
content: Hi guys n girlsI have a device here (a sony PS3), that I would like to make a fan PWM booster for, like this onehttp://www.ebay.com.au/itm/Playstation-3-PS3-Fan-Mod-Speed-Accelerator-Controller-run-cooler-avoid-YLOD-/190733529599All I want to do is basically add 30% (like in the link, as it seems to work well, not to noisy) to the PWM on the existing fan.I've been reading up on ways this can be done, lots of people use 555 and 556 timers but what kind of increase does that make.Does anyone know of a simple way to do this?Thank you

author: leham
author_rank: Regular Contributor
timestamp: September 13, 2015, 01:53:58 am
content: any ideas?

author: Psi
author_rank: Super Contributor
timestamp: September 13, 2015, 03:18:53 am
content: i have no idea how the ps3 controls its fans, but throwing a $1 mcu at the problem is my usual go-to approach.

author: leham
author_rank: Regular Contributor
timestamp: September 13, 2015, 05:54:11 am
content: I think it works the same as what PC's do if that makes sense..care to elaborate on MCU's?Thanks

author: michaeliv
author_rank: Frequent Contributor
timestamp: September 13, 2015, 07:43:25 am
content: What you are trying to do depends on what the wires going to the fan do.They can either be:- Ground + 12V + PWM signal- Ground + 12V PWM + tachometerIn the 1st case, it's easy, you just need to ignore the PWM signal and replace it with your own either generated with a 555(like you found on the net) or with a MCU(suggested by Psi).The increase in speed with a 555 can be adjusted with a potentiometer that you will include when building the circuit - R1 here:http://cdn.instructables.com/FIE/G47S/GXL5P0NJ/FIEG47SGXL5P0NJ.LARGE.gifInstead of a 555 you can use an MCU ... or an Arduino but that's too complicated.In the 2nd case it gets more complicatedThe easiest way would be to find another source of 12v, & connect the fan directly to it or add some series resistance to slow it down a bitYou should check the wires with an oscilloscope and see which case it is.

author: leham
author_rank: Regular Contributor
timestamp: September 13, 2015, 08:18:30 am
content: The fan only has:12v - GND - PWMI don't really like the idea of using a POT, the one I linked too seems to be just increasing the 'duty cycle' (I'm new to this).In the listing it says its based on a microcontrollerthis is what I want too make, i think ..http://benheck.com/forums/viewtopic.php?f=56&t=48494&p=463676&hilit=ps3+fan#p463676

author: michaeliv
author_rank: Frequent Contributor
timestamp: September 13, 2015, 08:44:18 am
content: Ok I see now - so you want basically: NEW FAN SPEED = FAN SPEED * 1.3Then yes, the easiest would be to use a microcontroller.It seems that you have the exact circuit you want to build there, including source code for the PIC - why not build exactly that ?However, even though that is for the PS3, it's showing that the fan has 4 pins, not 3.

author: leham
author_rank: Regular Contributor
timestamp: September 13, 2015, 11:36:45 am
content: my understanding is the the one i linked on benheck only changes the lowest speed, also do you think the buttons could be left out?thanks

author: MarkF
author_rank: Super Contributor
timestamp: September 13, 2015, 06:26:23 pm
content: It looks like you have the basic circuit there to do the job. You will need to verify that the PWM signal from your PS3 is 0 to 3.3V.Yes, you can easily leave out the switches, resistors and diodes if you don't want them.However, I couldn't find any source code. If you wanted to make any of those changes, you'll need to write new source code for the PIC.