A digital timer for your light switch. No wiring, one screw.
On Shabbos and Yom Tov you cannot flip a light switch, but you still want light at dinner and darkness when you sleep. Plug-in timers only control outlets, not the wall switch that runs the ceiling lights, and rewiring a switch means an electrician.
A battery-powered digital timer that mounts directly over an existing toggle switch with a single screw. A built-in motor flicks the switch up or down according to nine weekly programs plus a random night-time program. It fits multi-switch plates, works with fans and outlets controlled by a switch, and comes off without damaging the wall.
This started as an original JHG invention. While developing it, a product already on the market turned out to be close to the idea and needed only a few changes. Rather than build a competitor, JHG brokered the introduction between Kosher Innovations and the manufacturer. The tweaked version shipped as the Shabbos Smart Switch and sold in stores across the United States and Canada.

Sold at retail through Kosher Innovations. A companion version for rocker switches was discussed but never built.