Adafruit US-100 Ultrasonic Distance Sensor - 3V or 5V Logic

If you're like me, you've dreamed of being a dolphin, smoothly gliding through the water and using echo-location abilities to detect tasty fish treats. Until genetic modifications catch up with our desires, we'll just have to make do with this handy US-100 Ultrasonic Sonar Distance Sensor and a pair of flippers.

The US-100 is very similar to the popular HC-SR04 ultrasonic sensors, and even looks the same, but has a few extra tricks up its sleeve. This sensor can run from 3-5V, so you don't need any logic level shifters or dividers—just power from whatever your microcontroller provides.

You can use it in "HC-SR04" mode or in "Serial UART" mode. When the jumper on the back is removed, it acts like an HC-SR04 with a trigger and echo pin. When the jumper is in place, you use 9600 baud UART to communicate with the sensor. In UART mode, send 0x55 and read back two bytes (16-bit value) that provide the distance in mm, or 0x50 to read the temperature in degrees Celsius. This is especially handy if you want to use it with a computer and a USB-serial converter, or another device that can't handle the special timing needed for the HC-SR04 trigger/echo.

These ubiquitous sensors are really common in robotics projects, but they can also be used for automation, interactive art, and motion sensing. They work at a range of about 2cm to 450cm, although 10cm-250cm will yield the best results. In HC-SR04 mode (no jumper), you can use this sensor with Arduino, CircuitPython (for microcontrollers or Raspberry Pi), or MakeCode. In UART mode (jumper placed), you can use it with Arduino or CircuitPython.