jremington:
It is really fun to read and highly recommended!
Thanks. I have taken a copy and I have had a quick browse.
Maybe I did not express myself clearly earlier because that article (IMHO) supports what I was trying to say.
In the article the interesting vehicles are those with the added complexity of the "neurodes" because they do things that could not be achieved with a pair of LDRs and simple "point-me-at-the-light" code - the sort of code you would use to make solar panels face the sun as it moves across the sky during the day.
Now that I have written the previous paragraph I see that I should have included and simple "point-me-at-the-light" code in my earlier Reply. I will update it.
...R