Need Help with a turbidity sensor

Using Arduino Sensors
1

Hello Guys.

I'm new to Arduino but have some knowledge in programming.

I have a turbidity sensor from DFRobot, but I'm not able to get the informations from the sensor.
Can anyone Help to calibrate or initialise correctly the sensor?

Thanks so much

2

Give us a link to the device, a circuit showing how you it connected, and, a program.

Also what it is and is not doing now.

Weedpharma

3

The code:

void setup() {
Serial.begin(9600); //Baud rate: 9600
}
void loop() {
int sensorValue = analogRead(A0);// read the input on analog pin 0:
float voltage = sensorValue * (5.0 / 1024.0); // Convert the analog reading (which goes from 0 - 1023) to a voltage (0 - 5V):
Serial.println(voltage); // print out the value you read:
Delay(500);
}

And the sensor is connected tu Analog1 on the dfrobot lcd shield that is connected on the dfrduino.

I just get une value: 0.04v

4

the sensor is connected tu Analog1

Your program reads Analog 0.

5

jremington:
Your program reads Analog 0.

But the code was copy-paste. Sorry ma bad.
I'm reading the correct analog. but no way to get it working

6

Please read "How to use this forum" and post your code correctly, using code tags.

7

Hi,

This could help you. I am using one of these sensors for teaching purposes, and I considered that:

  1. The output voltage (Vout) of the sensor is inversely proportional to turbidity, so,
  2. The clear water have a 0% turbidity, and
  3. Turbidity of 100% means a fully opaque object,

So, I the equation for turbidity (in relative percent units) can be as follows:

Turbidity = 100 - (Vout/Vclear)*100

You can get Vclear when you put the sensor in clear tap water.

Best regards.

8

Consider various dilutions of strong coffee for test samples.

9

mcarmona:
Hi,

This could help you. I am using one of these sensors for teaching purposes, and I considered that:

  1. The output voltage (Vout) of the sensor is inversely proportional to turbidity, so,
  2. The clear water have a 0% turbidity, and
  3. Turbidity of 100% means a fully opaque object,

So, I the equation for turbidity (in relative percent units) can be as follows:

Turbidity = 100 - (Vout/Vclear)*100

You can get Vclear when you put the sensor in clear tap water.

Best regards.

Thanks mate for the tip.
But I need to have the value in mg/L. I have some liquid solutions to test, from 26mg/ to 360mg/l.
But in this moment, I have to find a solution to adjust propoerly the sensor, because when I adjust the screw it shows 4.40v, but when I put the plastic back, this value change.

10

The value of turbidity is not changing even after changing the mediums.can anyone help on this issue.

Thank you

11

If you want to calibrate these properly, you need to look up Formazine.
It's a milky solution that mimics cloudy water.
It's the accepted primary standard for turbidity measurements that are often expressed as Formazine Turbidity Units or FTU.
There are some doubts about the carcinogenicity of one of the ingredients, so it might not be possible to do safely outside the lab environment.
If you don't need absolute measurements, a couple of bits of clear and translucent perpex or similar can act as stable standards for checking the instruments' stability.
What you haven't said is what medium you are testing.
You can lash-up a crude turbidity sensor by just using an infrared LED and a matching photodetector.
Professional instruments quite often have several sensor typically straight through and at right angles to the illuminating beam to measure scattered light and compensate for component aging.

1 Like
12

Have you tried the DFrobot forum since its their sensor?

13

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