Please read manual PDF file carefully before buy this item available: here
Some basic soldering skills is required to use this item. One wire (not included) need to be soldered to get it work.
The purpose of this device is to control the behaviour of light emitting diode responsible for hard drive activity depending on the activity on the input pin. The LED driver compares the voltage on this pin to a reference value of about 2.7V. As soon as the measured voltage drops below that value, the open-drain output of the device will be pulled low. Although the driver was initially thought to interface with RaspberryPi computers, it can be also configured for operation with other devices, such as HD drives or CompactFlash-to-IDE converters. The open-drain output allows variety of applications beyond the use in Amiga computers.