Just a quick heads-up: if you want to replace the default iOS 7 lock screen clock with a binary clock you should check out a new tweak called Binary Clock 7 by developers Gilles Petit. The tweak comes with its own dedicated preference pane in Settings.app where you can enable/disable it on demand, hide/show the date on the lock screen under the binary clock, and pick a theme for the binary clock. The tweak also comes with 3 bundled themes 3D, Cat, and Default, but you can make your own and place them in the directory displayed in the preferences pane to apply them. Binary Clock 7 is available for $1 on Cydia Store via BigBoss repo.
If you don’t know how to read a binary clock, jump over the break to check out a video tutorial…