Makers, developers and enthusiasts building distance related projects may be interested to know that the HC-SR04 ultrasonic sonar distance sensor is now available to purchase directly from the ...

But with his long term goal in mind, he also modified the HC-SR04 sensor by removing the on-board pull-up resistor and adding a new one on the connector side to combine the signals.

Sonar is a great sensor to add to any small-scale robot project. And for a couple bucks, the ubiquitous HC-SR04 modules make it easy to do. If you’ve ever used these simple sonar units, though ...