USB HDD spin down

[Davem]

I'm also having problems with the spinning down of my external hard drive (500 GB, 3,5" Iomega in casing). The problem is that it won't spin down. Not after the standard 5 minutes and not on command.

$ sudo hdparm -y /dev/sda1
returns:

Terminal

/dev/sda1:
issuing standby command
SG_IO: bad/missing sense data, sb[]: 70 00 05 00 00 00 00 0a 00 00 00 00 20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

After some searching I found a lot more people facing the same problems and their is an alternative: HD-idle.

After installing the predefined package of Termo Termo, source of the threat

Copied the .deb file to my pi and installed by:
sudo dpkg -i hd-idle_1.04_armhf.deb

the service can be started (the standard spin down is set to 600 sec.):
sudo /etc/init.d/hd-idle start

after a test, the harddrive still doesn't spins down:
sudo hd-idle -t sda

I cannot produce any log files with:
sudo hd-idle -t sda -l /home/xbian/hd-idle.log

hd-idle is active because: sudo hd-idle -help is returning the options.

Somebody having any idea's how to spin down my external hard drive, all tips are appreciated?