Dear All,


Sorry for not replying for a long time. I have been busy. The sensor must be relatively small in size and fit in the road under the car. I think the inductive way is good, but I am not sure it will work well under all conditions. In any case, I need a "background" reading for comparison.

Optical recognition of the car seems interesting. The cost of a camera is very low these days. However, it may require too much software that I am not capable to write :(

Also, for information, I will use a timer and wake up the system once a couple of seconds as one of you suggested.

IR is out of the question. I have tried it. There are too many spurious triggers because of the IR from sun.

Again, Thanks for the many suggestions. I will do some experiments and let you know the results.

And, if anyone has more suggestions, please let me know.


Jesper