Hey chaps, I've been trying to get an ultrasonic sensor to work on my little robot project, the first one mostly returned 0 so i suspected hardware failure and purchased a new five pack.
I'm using SR-04's and the newping library. They all work fine but I get erroneous readings constantly, only when it's sat perfectly still do I get decent reliable readings and even then its not perfect.
I've checked the voltage and its fine, the unit is affixed well but I just don't get anywhere with it.
Are they all just crap and do i need to look at different options for measuring distance?
Think about the environment also. I was using one of these which didn't seem to give good numbers, but part of the return signal was coming from the element I aimed the sensor at, and part was coming from fixed objects behind the target object. The moral would be that you want as narrow a beamwidth as possible, and I don't think any of the cheap ones can achieve that.
I think that HC-SR04 Ultrasonic sensors are good for small projects. I do not think that it is the hardware issue. I am working on these sensors currently, I think they produce fairly accurate results. probably you can share with us your code and see how other people can help?
Advanced sonar techniques will give much more reliable results, but you pay much more
money for that. Cheap units wait for the first strong echo without gain-tracking, so nearby objects
off-axis can have a strong influence. Better units gain-track with distance (the sensitivity rises
with time), but real sonar uses lots of signal processing to distinquish signal from noise.
