No easy way to power a 12 V fan onboard?


#1

I use the Scythe Mini Kaze 40 mm Silent Case Fan (https://www.amazon.com/gp/product/B000LB0M8S/ref=oh_aui_search_detailpage?ie=UTF8&psc=1) to cool the CPU on one of my other dev boards, drawing power from the 40-pin Low Speed Interface, but from what I can tell there is no 12 V header on the board anywhere. Has anyone found a trick for this?


#2

if you are using 12v to power the board pin 36 and 38 are sysdc_in ie, the voltage that comes in from the barrel jack.
btw why such a a big fan?


#3

40mm isn’t so big, and this fan has a very low current draw; I selected it for quiet operation over size. The reason I require cooling beyond what the heatsink provides is that I’m intending to use it for some CPU-heavy transcoding functionality, and so maintaining peak CPU frequencies is desirable.


#4

There can’t really be a 12v fan connector because there isn’t usually any 12v power rail on these designs. The power input for 96Boards is 6.5 to 18v and this is usually downconverted to 5v for USB and often to something lower than 5v that the PMIC “likes”.

As Sahaj says, the closest equivalent is the SYS_DCIN which you can use safely for this because you know what power supply you are using. The LS connector was designed so both 5v and SYS_DCIN are both adjacent to a ground (so both can be accessed with a 2 pin header).


#5

I got a fan running on mine. not I just have to build a fixture to suspend it over the heatsink. works well though


#6

are there any good leads on a compatible fan case? I can’t find anything on the googles


#7

best bet is to get them 3d printed, like i did https://github.com/ric96/hikey960-case

or have laser cut case like @danielt, maybe he can link his design

what ever it maybe, you will nee to fetch a fan, most fan labelled “Raspberry pi fan” should work with the 5v pins


#8

yeah. I just discovered that my local city library has a 3d printer. I think I’ll try it


#9

I never mind showing off my cases (although even using a “turtle” to draw the shapes the python code is becoming very hard to read… mostly because I love rounded corners so much)! Anyhow I keep they all in one massive repo alongside all my other laser cut objects:

The art/ directory is final customized artwork… if you want to add your own engraving layers then try 96boards/ instead.