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†Low watt, high power server†- Part 3: SATA HDD activity LED
8 November 2011 20:30

In my process of setting up my new servers i was missing the good old harddisk activity LED there was on the old PATA harddisk where you can connect an LED to each drive, so i have looked into how to do this on the SATA harddisks.
There is always a LED connector on the mainboard but that is just showing the activity for the controller chip on the mainboard and not for each harddisk,
So after some internet searching i then found two things. one, a lot of posts around the net there was trying to do the same thing but was unable to get it working and number two was that there was a pin 11 in the SATA power connecter there was labeled as "activity indication" on supported drives, so it seems that you just have to connect a LED to that pin.... how hard can that be.

I then researched and was reading a lot of posts on the net and then found the information, if you connect the SATA power cable to the connector on the harddisk then the PIN 10+11+12 is connected to the GND and because this PIN 11 there is the activity pin is pulled down to GND then it will not be able to drive a LED and show the activity, so it has to be floating and not connected to GND..... but that is not as easy as it sounds.

Here you can see the SATA power connector (the big one of the two) and what signals there is in the connector.

Here i have pulled the SATA power connector apart so you can see how it is connecting and note that each wire is having a connection to 3 pins and there for it is not very easy to just disconnect the pin 11 in the power connecter and then reconnect another wire for the LED and this power connector is the only one i have there can be pulled apart, all the other ones i have cannot be open up.
Another way is to disconnect the pin 11 on the harddisk drive and then connect a wire on the print board, but i donít like that as that will break any warranty.

So i was looking for another way to do this and was thinking that there must be some sort of adaptor on Ebay that i can get for a low price and use to this and after some search time i then found this adaptor.

It is perfect because you can see each connection between the two connectors and easily modify it to the need i have.

Here you can see the cable connector, the adaptor and the harddisk drive as they will be connected.

Here I have drilled a hole in the connection of pin 11 between the two connector and there for it is no longer connected to the GND.
Then i have clean off the green stuff so i can connect the wires to PIN 4(GND), PIN 9(+5V) and PIN 11(activity)

Here i can connected the 3 wires to the adaptor and Black is GND, Red is +5V and White is activity.

Here is a diagram of how the LED is connected to PIN 9 and 11, only connect one LED and a 1K resistor as it is limit how much current that there is in the harddisk for the activity led.
So if† you like to connect more then use a optocoupler to make sure that there is not pulled to much current on PIN 11.

So now i have a flashing LED for the harddisk activity on each drive and i have not changed anything on the harddisk drives and/or the cabling so the warrant on the disks are good.

So if youíre getting the SATA adaptors from eBay like this one then it is not that hard to get the led to work and it is nice to now have a led for each harddisk drive.

Tooms @ 8 November 2011 20:30 | Direct link

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