Stellaris launchpad driven audible chirp sonar

Sonar based detection is commonly used in many areas. Starting with animals – bats and dolphins use sonar for navigation and hunting. People also use this technology in many areas like in car parking systems (parktronics), in robot navigation. High frequency ultrasound is used in medicine for visualization and anomaly detection. Ultrasound has very wide practical use as it is non-destructive way of seeing things that naked human eye can’t. Today practically everyone can do simple experiments with ultrasonic modules that cost pennies. You can get modules that work in air that can be used for measuring distances and even for robot navigation that detect obstacles. Jason, wanted to move things from air to water. As we know ware sonars are also intensively used in many areas like naval navigation or fishing. For his experiments he’s chosen Stellaris Launchpad microcontroller board which sends and listens to audio signals reflected for various obstacles and surfaces in water. He decided to construct chirp signals that were sent from piezoelectric buzzer. Signals were detected with mic and audio amplifier module. The rest work… Continue reading

Sound Based Wayfinder

This is a final year project by the students of Cornell University and utilizes ultrasonic range finders and haptic feedback to facilitate indoor navigation for the visually impaired. It uses auditory cues, such as sounds from the natural environment or sounds created artificially, to determine an individual’s surrounding physical space for the purpose of navigation. The device is a head-mounted navigation system with a wearable tactile sensor connected via a long flexible wire and also instructs the user to turn either left or right depending upon the obstacles. The microcontroller used for the ultrasonic wayfinder is the ATmega1284 which is mounted on a custom made PCB. Apart from it, there are vibrating-disc type motor which were used as a haptic feedback. The device detects objects quickly with 1 inch resolution between 0 inches to 254 inches. However the accuracy will mostly depend upon the ultrasonic sensor used. The project is entirely made for indoor use as it can’t detect obstacle placed at 5 meters. They also have a plan to put on an additional range finder mainly on the head… Continue reading

A Low-cost range finder using SONAR technology

Submarines navigate underwater by using SOund Navigation And Ranging as the bold letters suggest we commonly call it sonar. The sonar technology uses the concept of acoustic listening to range and navigate. This concept is based on the fact that sound travels at a rate of about 340 meters per second and the concepts of echoes, thus by sending a sound burst and listening to the echo one can determine the proximity of the object where the echo originated. Adding sonar capabilities to your embedded project has never became is easy and this cheap, with just 200 bytes of code and a little soldering you can add proximity, presence detection and distance measurement capabilities to your beloved projects. It uses the PIC16F877A’s PWM to generate the initial 40KHz sound burst while using the PIC’s ADC to detect the bounced back signal. Ultrasonic piezzo transducers are used to transmit the burst and receive its echo. The firmware was written in microC while software induced delay is used to eliminate mechanical echoes that could lead to wrong measurements. Continue reading