TomGeorge:
Hi, have you measured the supply voltage at the sensor, and have you tried any bypassing there, ie 10uF, 330uF at it PCB.
330nF is good on the 78 series reg but they also like 10uF on their output.
Are all you gnds good?Tom....
I do not think that that is because of regulator capacitors since I have also build 5V regulator and supplied all sensors connected to Arduino 5V pin. I think thae problem is totally because of HC-SR04 Ultrasonic sensor because we have used one and suddenly it did not work and replaced it.
If anyone has an experience with HC-SR04, I need help with the delay term. I think that delayMicroseconds(1000); is the problem because pulse delay is either short or long. We have just find this code and used it because it was working well. I will try changing delay and code a bit to see the result. Can this be the problem?