A magnetic sensor assembly measures changes in the position of a lever arm. The brake device can adjust the magnitude of part of a total braking force generated at a time of emergency braking of the car. A buffer layer is formed on the substrate by coating or deposition, and then a diamond film is coated thereon, fitting the shape of the required diamond film. For subsequent messages to the recipient, the sender determines from the counter data whether the secret key may be reused; if the secret key is reused, the sender updates the counter data. A keyboard and display are provided on the fluid delivery nozzle to provide an operator interface during the fluid delivery transaction.