The HC-SR04 sensors are simple to use. Let's take a look!

  • Vcc - Power pin - this sensor requires 5V power for best results.
  • Trig - Signal can be 3V or 5V.
  • Echo - "Return" signal is 5V logic - the sensor comes with two 10k resistors to use as a divider to convert the 5V logic level to a safe 2.5V that you can read with your 3V device.
  • Gnd - Ground pin.

The US100 is nearly the same except it is capable of UART.

  • Vcc - Power pin - this sensor can run at 3V or 5V.
  • Trig/TX - Signal can be 3V or 5V in HC-SR04 compatibility mode.. Works as TX in UART mode.
  • Echo/RX - Signal can be 3V or 5V in HC-SR04 compatibility mode. Works as RX in UART mode.
  • Gnd - Ground pin.
  • Gnd - Ground pin.
This guide was first published on Dec 04, 2019. It was last updated on Dec 04, 2019.
This page (Pinouts) was last updated on Oct 25, 2020.