Ultrasonic Sensor default value

[joonyeechuah]

What's the expected behavior of the Ultrasonic Sensor when no signal is returned? (i.e., angle of attack is 45 degrees or more) The original lego sensor spec says the device returns -1 when it doesn't get a signal in continuous mode. (There's also a burst mode that I don't think is supported by BrickPi.)

[mwvaughn]

The BrickPi library abstracts this behavior and returns maximum distance (255). Basically, I think you can count on 0-255 coming from the sensor at any given time.