Ultrasonic Distances

[foobert]

the ultrasonic sensor does not return an analog value. it returns the time it takes sound to make a round trip out from the sensor to whatever's out there and back to the sensor. the distance can be had by multiplying that time by the speed of sound through air. you need to know the scale of the units returned by the routine that reads the sensor. microseconds, milliseconds, whatever.

or you can put something a foot in front of the sensor and see what kind of reading you get. note that there will be a little jitter, so you'll want to average a couple of different readings and then rather than comparing future readings to the value you get, check to see if they're close. for instance...

if ((new_reading >( one_foot - fudge_factor)) and (new_reading < (one_foot + fudge_factor))) {...

or you could wait for a reply from someone who's used easyC

Originally Posted by irishninja

What is the analog number for 1 foot for the ultrasonic sensor?