fan running even when drives spinned down - FANTEC hard drive housing

wolf8auer · 22. Januar 2020

I have my hard drives in a FANTEC QB-X8US3 8x3,5" SATA HDD USB3.0 eSATA.
Connected via USB to a Rock64.
On the FANTEC I have SYNC mode on so that when the Rock64 is off, the device goes to sleep mode. In sleep mode the fans are off.

I don't mind running the Rock64 all the time, but I don't want the fans to run when I don't need the drives.

I am looking for some options...
What I tested:

method	fans off?	cons
`sudo poweroff` the Rock64.	yes	starting the Rock64 when I need it takes some time
unmount all drives `sudo umount-l /dev/sda1` stop samba `[font='Consolas, Courier New, Courier, monospace']sudo servicesmbd stop[/font]`	no	-
standby (spindown) drives `hdparm -Y /dev/sda1`	no	-

Topics I would be interested in are:

sleep mode on SBCs? with halt -> Could this low power mode trick the FANTEC into sleep mode
shut down the USB Interface (and switch it on when needed) (USB-port powering & CEC support)

Adoby · 23. Januar 2020

Put a current sensing switch module on the 12 volt line, aND use that to control the fan(s). Here is one that should be suitable. It has a delay as well, so the fan can run a short while after spindown.

https://www.amazon.com/dp/B01N…m_r_mt_dp_U_tbpkEb3D8SH4N

More primitive: Build your own power sensing switch. Amplify the voltage drop over an extra length of wire using an op-amp and use the output to drive a mosfet that controls the fan. Should be compact enough to fit inside.

Edit: The module might be too small for 8 x 2A.

wolf8auer · 23. Januar 2020

Sounds interesting!
The module looks good. How would I connect the module with the Fan?

Adoby · 23. Januar 2020

You route the 12 V power to the HDDs through the module. Or if there is an external 12 V supply to the entire enclusure, that current. There are other modules for AC current detection that also might be used.

Then you connect the fans to the module output.

But the module above is only for 10A. 8 HDDs may draw more power than that when spinning up.

The OP-amp and MOSFET idea is the same, only you need a very low OHM voltage drop resistor to provide a way to detect the power used. The voltage drop over a length of cable might be enough. Then you could use a MOSFETs to turn on/off power to the fans if OP-amp detects a voltage drop over the cable = current used.

There also are temperature sensing modules and even temperature sensing fans. Temperature sensing like this might be iffy, it might not react fast enough, but it could perhaps be much safer if you have one fan always running at very low speed to make sure a temperature rise is detected quickly.

https://www.amazon.com/dp/B00V…m_r_mt_dp_U_LExkEbVJFKYS5

Then all you need is to connect the fans to the module and power the module. One fan might be always on with a resistor to lower speed (and noise). Much simpler than current sensing, but less precise.

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