I have a ESP32, and have 4 digital signals. At the beginning all 4 are low, and as soon as any one of those goes high, the other 3 follow up. I would need to measure the time between the first one and the other three.. The problem is that the time delta is very small. The other input should be high between
0.0003 ms and
0.023 ms. I am trying to measure the time sound takes to travel inside a 15 cm steel plate (about 3150m/s).
Is there any way (also with cheap external components) to measure such tiny intervals?