[...] why WHOULD it be difficult to achieve what Bert wants?
Bert has never build any electronics and have zero experience/knowledge in neither datasheet reading, construction nor design - according to himself.
New Years eve, Bert posted this
I'm totally new to electronics and robotics and after digging into all this for a couple weeks I am realizing what a colossal task it will be for me to build a circuit and control it from the internet. It seems a number of folks have accomplished this on this forum and I am interested to see if anyone would either design my idea for me or walk me through a design for some cash (and how much cash you'd do it for). There actually won't be a whole lot of robotics involved. Basically all I want to do is control a whole bunch of digital potentiometers and relays through a nice looking flash web interface. Please PM me if interested.
Bert simply asks questions that tells me, that he have no chance whatsoever of doing this on his own. A couple of years of building lesser projects might help some, but Bert doesn't just want to build this project, he wants to design it as well.
I know very talented constructors with many years of experience that goes into self destruct mode if asked to design anything, even a one transistor mic amplifier.
All in all, I think the best advice is to drop it, rather than be disappointed and shy away from electronics completely, after burning a lot of cash on a project that will never fly.
If anybody have time and patience for designing Bert his system, drag him through every step of construction and trouble shooting of the prototype and generally spoon feed him, he may be able to get it done, given enough time.
I know I haven't - I have plenty of larger not-for-myself-nor-for-money projects on the shelf, like an electric miniature 1967 Corvette ("go-cart" like) for my grandson and a kick-behind dolls house for my grand daughter - and to quote the Norwegian poet Bjørnstjerne Bjørnson (which btw. translates to Bear-star Bear-son): "Hvad du evner, kast af i det nærmeste krav"
Which means something like: What free and available resources you have, spend them on what/who your main priorities are" and family, my little gold nuggets in particular, wins hands down, over an all too optimistic newbie stranger thousands of miles away, in getting me to do stuff
Or he can pay his way, but I don't think he can find an engineer that will design and build this for a price that he's ready to pay - research, design, prototyping, layout, construction, boxing up etc. will easily run into the 30..40 hours range and while I have no idea what engineers charge in the US, my time is around $200/hour, if I'm not doing charity, depending somewhat on the exact project.
Beginners should begin with beginners projects (hence the name), then they learn something, rather than end up with a load of expensive junk that they don't understand, but unfortunately, it seems that the less they know, the larger projects they think they can muster - it's crawl, walk, run, no skipping
Common sense suggests that if one replaces pots by same value digi pots and switches with relays (with few transistors and diodes) all should be fine (as long as soldering does not mess anything). Is there something more to consider?
You've been in this long enough to know that this kind of "common sense" is a bit too simple to hold true - how many of your own designs have worked at first try?
Clock speed is not that important as long as you have
Might not be the controller clock speeds that Bert means.
External crystal is required if uC does not have internal oscillator [...]
An external X-tal on the controller will be a very good idea, both for getting reliable comms and for synch'ing purposes - if it goes into audio circuits, even more so.
BTW. The lack of info on the end purpose makes it impossible to find the best solution, which could be something simpler than what Bert figured out.