makarov132:
To save money, I bought a two-piece ultrasonic sensor (which was not designed for Arduino). It does look similar to other ultrasonic sensors. I have looked around and I can't find an informative data sheet or a tutorial. I don't even know which side is negative! The codes on the sides are: UST-40T, 400SR 04 62. Please help!
You may have attempted to save money, but you did the opposite. It will be far more expensive and complicated to get these to work. Also, how could you possibly save money? Complete HC-SR04 sensors are like $3 shipped!
Tim