That sounds like a good plan! If the customer in this case had any brains, he would probably find something already built that does what he wants. Surely somebody already makes an outdoor sign that displays time and temperature. That's not a new idea, after all.

It's really hard to get customers to specify things. One of my favorite lines is, "People don't know what they want until you give them what they asked for." I think the main problem is that it's much harder to synthesize something that doesn't exist than it is to criticize something that does.

There are (at least) two solutions to this. One is what you are doing--write the specificiations yourself and charge the customer for doing it. Often that doesn't work, however, because the customer won't look at the spec unless you literally read it to him. And even then, it may be hard for him to imagine what you have specified until it's too late.

Another way, and the one I like, is to build some sort of quick and dirty mockup or prototype that will give the customer something to point at and look at while you talk with him about what he wants. If he has something tangible in front of him to complain about, it will be a lot easier for him to say things like "this part is great" or "can we move this switch over here" or "the whole thing is too slow" than if he is just reading a spec.

If you're talking about software, just some quick, do-nothing screens built with Viausl Basic or whatever can be enough. If it's hardware (like your sign), then throw something together with cardboard and paint to see what it looks like. This seems like an especially good idea for your sign, to confirm the specs from the web site that Russell gave you. Paint some 250 mm characters on a piece of cardboard, step back 100 m, and see for yourself what they look like! Shouldn't take more than five minutes.

-- Russ