Can it be put in a box? I think democracy is a set of values and norms, not a device. If people (either powerful people or powerless people) do not believe that they will get the results they want out of democracy, the fact that a democracy box exists will not change their minds.

In particular, if the democracy appliance you're imagining includes voting machines, there is zero technical way to prove that a voting machine is reporting trustworthy results if you cannot rely on trustworthy humans to be part of the proof. (Standard auditing mechanisms include things like "representatives from both parties," which doesn't help if you suspect the two major parties are colluding to suppress outside viewpoints.)