I've own 2 original Nex-5's for several years now and other then hacking the shutter button and using a USB relay type device you can't control it with a PC. To be honest the hacking part is more trouble then it's worth and you would still need to code an intervalometer program for the relay.I have 2 of the standard DIY intervalometers that I use for 30 second and under exposures. Since the Nex-5 requires a second IR blast to close the shutter in bulb mode I use a different IR intervalometer. For longer exposures I use a gentLED-AUTO intervalometer. James at gentLED was kind enough to program a 10 second delay between exposures. That gives a little cool down time for the sensor. The device is simple to use and very compact and provides that second IR signal to close the shutter.
http://gentles.ltd.uk/gentled/auto.htm I am extremely happy with this intervalometer.With the intervalometers I have found no need for a computer to be connected to the camera.Mike