If you’re like me, you’ve dreamed of being a dolphin – smoothly gliding through the water. Using your echo-location abilities to detect tasty fish treats. Until genetic modifications catches up with our desires, we’ll just have to make do with these handy HC-SR04 Ultrasonic Sonar Distance Sensors and a pair of flippers. 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 about 2cm to 400cm away, but we think 10cm-250cm will get you the best results.
These sensors are fast, fairly easy to use, and low cost. They do require powering from 5V for best results: connect GND (ground) and VCC to 5V power. While the Trig signal can be 3V or 5V, the ‘return’ Echo signal is 5V logic. For that reason, we include two 10K resistors, use these as a divider to convert the 5V logic level to a safe 2.5V that you can ready with your 3V device.
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.