3 What makes these motion detectors active? Since they need to emit an ultrasonic sound wave, they require an active source of energy to generate the sound wave they emit. Active ultrasonic motion ...

Divide by the mass of the cart, 0.485 kg and we get the velocity change: $\Delta v =$ 0.65 m/s. At the same time as we measured the force, we measured the position and velocity of the car with an ...

[Circuit Valley] has an IKEA Vallhorn motion sensor for a teardown, it’s as you might expect, a passive infrared sensor (PIR) sensor coupled with a Zigbee interface. Inside the ultrasonic welded ...