Here is another gadget that turns your regular watch smart. The Smart Buckle replaces the clasp on your watch strap. It fits any standard 20mm watch band. Just download the companion app, and you will be able to sync the device to your iOS or Android phone.
Smart Buckle comes with 3-axis gyro, angular velocity, and motion sensors to measure distance, calories burned, pace, and monitor your daily activity. Costs as low as $39 at this time.