Hi kchriste,
Thank you for your reply.
I have visited that site, and spent some time reading and re-reading various pages there.
It seems that using the ethernet system to interact with remote devices is a well known established arrangement. However, i could not find any mention on that site of the 'wake-on-lan' facility.
As i'm sure you know, the 'wake-on-lan' facility is partly a function of the ethernet card, and partly a function of the motherboard, or the supporting electronics for the ethernet card.
I found the whole site difficult to read and understand, but there some parts which were easily understood.
I want to access the remote ethernet card from my small LAN, so it will have to have a run of cabling over to it, which is fine. I also want the ethernet card to respond to the wake-up and provide power to a simple set of sensors for temps, and maybe for flow sensors arranged on my water pipework.
I dont really want the ethernet card to be housed in another computer, mainly because of the start-up time, but i would imagine a microprocessor unit could manage to feed the ethernet card with the signals from the sensors without a problem.
I would also imagine that the time taken for the ethernet card to respond to the wake-up, and start its local power supply, and to interact with the sensors would be a very short time.
But i can only guess at that, i have no experience along those lines.
My guess would be less than two seconds. Maybe less than one.
If its difficult or unreasonable to get the microprocessor to output an html page with the sensor figures shown in a picture of the pipework, then the picture of the pipework could be done on my PC which would be accessing the remote ethernet card.
Then hopefully just get the sensor figures from the remote ethernet card, to be shown on the picture.
Or maybe there is a completely different way to do this.
There may be another way to access remote sensors that i have not thought of.
Thanks for any comments or suggestions, John