3 ms·

Embedded devices can be laggy at times. More efficient for the car to estimate the distance and power of the transmitter.

• mikeash 8y ago
  You’ll just estimate the distance and power of the relay. Roundtrip delay is the only thing you can’t fake.
  • ryacko 8y ago
    The relay could emulate a reasonable power output, but that requires more precise measurements and would discourage thieves.