Time lapse camera update

My attempt to make a time lapse system has foundered again it seems. I had bought a custom made intervalometer and had planned to use it with my D70 to make a system I could run off a 12 v battery. However it has proven to be a very flaky set up. Unless the LED is in exactly the right position it tends to not fire and after a relatively short amount of time the camera switches back to it's default setting rather than the IR remote setting. It would be so much easier if this could be set as the default but Nikon never thought of this as usual. I'm beginning to suspect that the intervalometer is simply not adaptable enough anyway. I might have another go using the option in the Capture software running off my main PC rather than the dodgy netbook I was using which just crashes all the time. Buying a new laptop for this is not really justifiable at the moment. But I can eliminate all the other issues it might still be a viable option: a time lapse system which isn't 100% reliable is next to useless.