This vibrating crochet hook can be used to measure the resistance of a crochet stretch sensor while it is being made. Continuity and resistance can be measured while the sensor is being crocheted. The vibration motor is powered by a 3V coin cell battery. The less resistance, the stronger the crochet needle will vibrate.
Tools for E-Textile Techniques >> http://www.plusea.at/?p=2220
Instructable >> http://www.instructables.com/id/Vibrating-Crochet-Hook/