Now thats what I'm talkin bout!
Thats exactly what I'm after, 5 miles would be great and such a small circuit. Brilliant. Whats the size of the stack? I'm wonderin if you can send me a copy of the diagram and parts list. Then all I need is a rechargeable that can power it and a solar charging circuit of similar size to that circuit (That I think may be pushing it, but may be possible), then I got it all.
If the solar idea isn't possible (sizewise) then I'd need some other way to charge it but having a socket is a risk as it needs to be weather/water proof. The solar would be great because then I would never need to open it so I could seal the casing completely. Changing battey often would be too much hassle although I am going to work in a 'condition' switch that will only turn it on under certain conditions.
I'm sorry I have to be so vague about this but I have agreed to it so I'm bound by that agreement.