If you have a mobile robotics application, a good way to detect what is in front of it is to use a sonar. Then again, just one sonar unit doesn’t really tell your robot that much about its environment; perhaps you should add another beside it to determine which way to turn to avoid an obstacle. Several more on the sides could also be advantageous, or even a few more for vertical sensing, or even…
Obviously this kind of sensing can get complicated quickly, and quite costly in terms of IO. Rather than using up all of your IO pins, the Octosonar board presents another option. Per its Tindie listing, it “Allow[s] you to connect eight HC-SR04 ultrasonic range sensors to an Arduino using the I2C bus and one hardware interrupt pin.” Additionally, if you need to use more than eight sensors, you can daisy chain multiple boards together as shown in the second video embedded below.
