I haven't tried it (I don't consider myself as handy with bare electric wires
and after all, I already have Chihiros doctor), but saw a couple of articles/videos.
Or translated article from Czech language https://translate.google.com/transla...il-twinstar-do
Just search for "DIY twinstar" and you'll find other pages.
Btw. if you want some new toy for the tank, I'd advise to check Sochting oxydator. It's interesting little thing, which creates pure oxygen from hydrogen peroxide in a controlled manner. I am aware of one US distributor, but you might be able to source it somewhere else too. http://www.aquariumoxygenator.com/