AVS Forum Special Member
Join Date: Jan 2002
Location: Ellicott City, MD
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If all you need is to control it via a timer then it should be a relatively straightforward circuit to build. Get a small project box and cut a USB cable somewhere between the connectors. Drill three holes in the box: two for grommets and one for a DC power jack. Insert the cable and grommets through holes at each end of the box and splice the three wires together (everything but the +5V line). Get a wall wart and a DC relay chip that are of compatible operating voltages (i.e., if the relay operates at +5V get a 5VDC wall wart). Install a DC power jack in the project box that's compatible with the connector on the wall wart. Connect the two ends of the USB +5V line to the input and output of a relay chip. You can mount the chip on a small project board or build your own from scrap PC material. Connect the positive and negative lines from the DC power jack to the Vcc input of the relay and ground, respectively.
The timer needs to be programmable so you can set the start and stop times. A simple appliance timer used to turn lights on and off would work. Just plug your wall wart into the socket and use the output to power the relay. When the timer hits the start time, the power supply turns on, the relay is energized, and the +5V line of the USB cable is connected for continuity, allowing the USB devices to power on. When the time reaches the stop time, the power supply is turned off, the relay is de-energized, and the +5V connection is opened, turning off the USB devices.
There are probably more elegant solutions, especially if you want more precise control over the start and stop times. If you're just looking for a rough start and stop time then this may do what you want.