いろいろな場面で役立ちそう。手をかざしてスタートとストップができるデジタルタイマー

Learning Resources Digital Timer

3D Render of Digital Clock Countdown Timer - 15 Minutes

Raspberry Pi and Arduino programmable timer

A DIY digital clock with a twist | Arduino Blog

2 Pack Kitchen Timers Loud Ring Digital Timers for Cooking Magnetic Blue

Kitchen Timers for Cooking, Chef Cooking Timer Clock with Loud Alarm,100% Mechanical Desk Timer - No Batteries Required - Magnetic Backing, Exquisite Stainless Steel Body - Countdown Reminder Magnetic

Digital Kitchen Timer, Digital Timer with Large LED Display, Magnetic Kitchen Timer for Cooking, 3 Volume Levels for Classroom/Office/Home/Work/Study, Black (Battery Included)