Converting Voltage to Turbidity

Hi
I am getting a value of 5 for voltage when the sensor is placed in clear water. If I use the equation: y=-1120.4x^2+5742.3x-4352.9 to calculate the corresponding Turbidity, i get a negative value (-3651.4) whereas it should be 0. Any suggestions to resolve this please ?
I am getting a value of 5 for voltage when the sensor is placed in clear water. If I use the equation: y=-1120.4x^2+5742.3x-4352.9 to calculate the corresponding Turbidity, i get a negative value (-3651.4) whereas it should be 0. Any suggestions to resolve this please ?
2018-08-15 16:06:58 this is perfectly normal, as according the diagram where you got that formula from, you shouldn't get any value over ~4.2V (nor under ~2.5V) :

are you sure the onboard switch is on the analog position ? I feel like you might be reading the "digital" (binary) output.
I missed it first on wiki but it's clear once you have a look at the schematics.
ankou29666

are you sure the onboard switch is on the analog position ? I feel like you might be reading the "digital" (binary) output.
I missed it first on wiki but it's clear once you have a look at the schematics.
https://github.com/Arduinolibrary/DFRob ... ematic.pdfwiki wrote: Interface Description:
- "D/A" Output Signal Switch
- "A": Analog Signal Output, the output value will decrease when in liquids with a high turbidity
- "D": Digital Signal Output, high and low levels, which can be adjusted by the threshold potentiometer
- Threshold Potentiometer: you can change the trigger condition by adjusting the threshold potentiometer in digital signal mode.
