Ultrasonic Range sensor fluctuations/inconsistent reads?

Development Boards Arduino
1

Hi there,

I’ve recently started playing around with a Netduino and some sensors - specifically the ultrasonic range sensor (from seed studio). I’ve connected it to my digital pin.

If I aim it at the same place, I get fluctuations of about 20cm sometimes… usually from 85cm → 120cm at the same place? Any ideas?

Here are some environmental situations:

The 5V range sensor is on the breadboard with a LED and a resistor (330ohm)

Code:

while (true)

{

outPort.Active = true; // Put port in write mode

outPort.Write(true); // Pulse pin

outPort.Write(false);

outPort.Active = false;// Put port in read mode;

bool lineState = false;

// Wait for the line to go high, for start of pulse.

while (lineState == false)

lineState = outPort.Read();

long startOfPulseAt = System.DateTime.Now.Ticks; // Save start ticks.

// Wait for line to go low.

while (lineState)

lineState = outPort.Read();

long endOfPulse = System.DateTime.Now.Ticks; // Save end ticks.

int ticks = (int)(endOfPulse - startOfPulseAt);

lastReading = ticks / 580;

Debug.Print(lastReading.ToString() + " cm");