Calculating speed using an IR sensor

Using Arduino Sensors
#1

I am using the sharp GP2Y0A21YK IR sensor. The code below (taken from http://luckylarry.co.uk/) allows me to calculate the proximity of an object from the sensor

int IRpin = 1; // analog pin for reading the IR sensor void setup() { Serial.begin(9600); // start the serial port } void loop() { float volts = analogRead(IRpin)*0.0048828125; // value from sensor * (5/1024) - if running 3.3.volts then change 5 to 3.3 float distance = 65*pow(volts, -1.10); // worked out from graph 65 = theretical distance / (1/Volts)S - luckylarry.co.uk Serial.println(distance); // print the distance delay(100); // arbitary wait time.

}

Now I need to calculate the speed of an object as it moves away or closer to the sensor. any help?

#2

speed is rate of change of distance over time. Thus if you measure distance d1 at time t1, d2 at t2, calculate (d2-d1)/(t2-t1).

#3

how about float distance TFDU4301 IR sensor arduino code ?

#4