This is an Arduino-based Proximity Sensor circuit wired using the popular HC-SR04 ... If everything goes right,you should see the burning eye of the red LED when there is no object in the safe-zone ...

Instead, it relies on an ultrasonic distance sensor to detect a hand (or foot) waved in front of the door. An Arduino Leonardo runs the show, sounding a buzzer when the ultrasonic sensor is triggered.

To build this DIY buzz wire game, you'd need an Arduino Nano, a 9V battery, two LEDs (red and green), a buzzer, a seven-segment LED display, a shift register for the display, and resistors for the ...

In this mode, you can interface the HC-SR04 ultrasonic ping sensor with a servo motor and the main board (Only some reward tiers include the extra servo motor PCB and servo motor kit).

Enclosed are the ultrasonic sensor, a temperature sensor and an LED indicating the power status. On the other side of the CAT5 cable can be found an Arduino compatible board with an XBee shield ...