Making a better HC-SR04 Echo Locator
22nd January 2014
I have bought several cheap echo location circuits from AliExpress and I'm planning to use them in one of my robotics projects.
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| HC-SR04 Front View | HC-SR04 Back View |
They are very cheap especially if you buy a dozen you can get them bellow 2$ shipped. Once they've arrived, to test them, I wrote a quick C test program for an AVR board which displays the distance in cm to an obstacle. The results were pretty accurate for as far as 3-4m distance for hard obstacles. Unfortunately when there are no obstacles in front of this detector or when the obstacles don't have hard surfaces then erroneous results are returned.
I wanted to understand why this was happening so the first step was to reverse the HC-SR04 module schematic.
