Looking for a fun and easy way to add a bit more interaction to your LED-laden projects? Why not turn them into proximity sensing LEDs? Our hacker, [Will], is just getting into designing his own PCBs.

Now that we have discussed the theory about the sigma-delta modulator, let us design a simple proximity sensor that will detect an approaching hand and switch on an LED. A 0.5 mm 2 wire, 10 cm long, ...

This is an Arduino-based Proximity Sensor circuit wired using the popular HC-SR04 Ultrasonic ranging module,used here for non-contact object detection purpose. The HC-SR04 module includes ultrasonic ...