Hey all,
I'm trying to make a circuit that can detect the distance between itself and another object, using two 40kHz transducers and a PIC. A short pulse is sent out, and the time taken to receive the echo is used to find the distance.
I would like to trigger an input pin on the PIC when the echo is received. Unfortunately, the echo is only about 10mV, and the PIC requires about 4V for a pin to be high. I've tried using a set of three op-amps to amplify the signal, each with a gain of 10x, but the amount of interference is high and the circuit seems unreliable in general.
Would you say that op-amps are the best way to detect the signal? I am not interested in the amplitude, only the time at which the echo is received.
Thank you!
I'm trying to make a circuit that can detect the distance between itself and another object, using two 40kHz transducers and a PIC. A short pulse is sent out, and the time taken to receive the echo is used to find the distance.
I would like to trigger an input pin on the PIC when the echo is received. Unfortunately, the echo is only about 10mV, and the PIC requires about 4V for a pin to be high. I've tried using a set of three op-amps to amplify the signal, each with a gain of 10x, but the amount of interference is high and the circuit seems unreliable in general.
Would you say that op-amps are the best way to detect the signal? I am not interested in the amplitude, only the time at which the echo is received.
Thank you!