Arduino example code for the HC-SR04 ultrasonic ranging sensor. - sparkfun/HC-SR04_UltrasonicSensor ...

An Arduino compatible board (e.g. Arduino UNO): Arduino UNO / Arduino Mega A HC-SR04 ultrasonic sensor / A Ping))) ultrasonic sensor: HC-SR04 (Optional - For aqqurate distance values) A DHT ...

A fully integrated 3-D ultrasonic fingerprint sensor-on-a-chip is presented. The device consists of a 110× 56 piezoelectric micromachined ultrasonic transducer (PMUT) array bonded at the wafer level ...

Thus, they entered a heart rate sensor to our 2025 One Hertz Challenge! The build is based around a Wemos D1 mini, a ESP8266 development board.