polygot, I think your warning is a bit over the top.
True, I've never built anything electrical from scratch; just fixing broken things by soldering or reconnecting wires. But to abandon this project right here and now because I asked for advice is a totally ridiculous suggestion.
I'm not going to burn down my house, I'm not going to kill myself, and I guarantee I'll make a perfectly safe device. Maybe you should be warning about the dangers of potassium dichromate, since I've never had lab training either.
Sorry, don't mean to sound harsh, and I do appreciate your concern, but think back to earlier times when people cobbled together all kinds of apparatuses, and a darn good percentage of them lived to tell about it.