Know what little kids love more than playing the Nintendo DS Lite? Playing the DS Lite for long periods of time and holding it close to their face.
To prevent that, there this: the Health Control Game Timer. The ¥3,990 (US$40) doohickey has a timer with settings for 30 minutes, 60 minutes, 90 minutes and 120 minutes. If a player goes over the allotted time, the DS switches off automatically.
There's also a sensor that can gauge how close the player. If the player gets too close, an LED light illuminates, the DS Lite vibrates and makes a beeping noise.
The Health Control Game Timer fits directly in the DS Lite's Game Boy Advance slot. Shame the DSi doesn't have a GBA slot.