If you’ve done any significant experimentation with Arduino and Raspberry Pi robotics, you’ve undoubtedly come across the HC-SR04 ultrasonic sensor. These inexpensive units provide an easy way to allow your robot to see (or literally, hear) what’s in front of it. If you want to use a number of sensors facing in different directions, things get a bit more complicated, in part because they can be difficult to mount.
To solve this problem, Alastair Young, aka Red Hunter created the Trimount bracket system, which staggers 3 of these sensors on a PCB at 45 degrees. With the help of standoffs, two of the sensor units are mounted underneath the third in a nice compact package. Wiring is broken out on the back to allow connection with RC-style jumpers.
As illustrated in the video below, this arrangement can be implemented with a robot in order to calculate how it’s approaching a wall. This means it can make adjustments and avoid crashes much more gracefully than when using a single sensor. Four boards are included, so you’ll be able to cover the corners of a rectangular sensing setup as shown in the video below.