Build an Arduino based sonic pest repeller

Just in time for Summer, here’s a design for a sonic pest repeller. Carla Schroder developed this project which uses an Arduino Uno along with the WAVE shield and a Maxbotix ultrasonic rangefinder. This simple yet reportedly effective design senses critters nearing your garden plot and plays sound files (stored on an SD card) intended […]

Temperature compensation for an Arduino ultrasonic distance sensor

Sverre Holm writes: Ultrasonic distance sensors can find the range out to 2-4 meters and are popular in e.g. robotics. Here I look at how the accuracy can be improved by compensating for the variation of speed of sound with temperature. It actually varies quite a lot in air and around 0 C it is: […]

A simple posture sensor

Here’s a simple cure for your posture and the back pain blues, a posture sensor by Wingman: The simplest distance sensors are ultrasonic or infrared sensors. I went with a SR-HC04 because it is cheap and sufficiently precise. There are no special requirements to the controller so I am using an Attiny85. A small piezo speaker provides acoustic […]

DIY ultrasonic range finder

Zipppys123 is building a DIY ultrasonic range finder based on this design. Once it’s externally triggered a PIC12C508 is used to generate generate the ultrasonic pulse, and measure its echo. The ultrasonic pulse is amplified using a MAX232 TTL-to-RS-232 level converter, while the echo is amplified and demodulated using two op-amps and comparators. Via the […]

App note: Implementing ultrasonic ranging on PIC16 microcontrollers

This app note by Microchip describes how to implement ultrasonic ranging on their PIC16 family of microcontrollers. Object ranging is essential in many types of systems. One of the most popular ranging techniques is ultrasonic ranging. Ultrasonic ranging is used in a wide variety of applications including: • Autofocus cameras • Motion detection • Robotics […]

7400 competition entry: TTL based range finder

Udif entered the TTL based range finder into the Open 7400 Logic Competition. It uses an ultrasonic sensor to determine the distance to an object. The sensor outputs a pulse, the width of the pulse is proportionate to the distance measured. The sensor signal drives a clock which in return increments a counter. The clock […]

HC-SR04 ultrasonic Arduino library

Carl Nobile has developed and released an Arduino library covering the HC-SR04 ultrasonic sensor. He writes: “It features timing, metric conversion, and standard deviation methods, plus a few support methods. It is written in C++ to conserve the namespace. The conversion formula can be easily modified to optimize the accuracy of conversion at different distances […]

Arduino-based Tacit Project assists visually impaired

The Tacit Project from Grathio Labs is developing a wrist mounted sonar assistive device for the visually impaired. The hardware includes Parallax Ping ultrasonic sensors mounted in the glove which send distance measurements to an Arduino. The Arduino then activates small hobby servos to vibrate in the glove to communicate the relative distance to objects. […]

picoBAT: ultrasonic bat detector

Think you have bats in the belfry? If you have a PIC 12F683, ultrasonic piezo receiver and piezo speaker, micro-examples has a project that purports to detect the presence of bats and sound a piezo alarm. The schematic and C source are available for download. We can envision a modification which would transmit an alert […]