Does this datasheet of an IR distance sensor contradict itself?

Other Hardware Sensors
1

I am new to electronics and I purchased a GP2Y0A02YK0F distance sensor.

I am aware that they recommend a capacitor to be placed in the circuit to make the readings more robust as indicated in the datasheet and discussed in this thread

I am trying to convert the analog voltage given between 0 to 255 to something in centimeters.

Looking at the datasheet here https://www.sparkfun.com/datasheets/Sensors/Infrared/gp2y0a02yk_e.pdf

I see that it says that the output terminal voltage should be between -0.3V to 0.3V. It also says that the output voltage should be 0.25V at 20cm and 0.55V at 150cm.

Further down, there is a graph showing that there should be an output voltage of around 2.75V at 20cm. I'm really confused if I should expect 0.3V, 0.25V or 2.75V at 20cm.

Do suppliers normally give a formula to convert or they want you to find what it is based on the graph they give?

2

Loomy__:
I see that it says that the output terminal voltage should be between -0.3V to 0.3V.

That's the absolute max voltage that output pin should see if you connect someting to it that could feed back voltage into that pin.

Loomy__:
It also says that the output voltage should be 0.25V at 20cm and 0.55V at 150cm.

Read it horizontally. At 150cm, the output could be 0.25-0.55volt, but typically is 0.4volt.

Loomy__:
Further down, there is a graph showing that there should be an output voltage of around 2.75V at 20cm. I'm really confused if I should expect 0.3V, 0.25V or 2.75V at 20cm.
Do suppliers normally give a formula to convert or they want you to find what it is based on the graph they give?

The graph shows the typical output voltages at different distances.
Leo..

3

Thank you for the reply! I know understand how to read that table. Although this data does not seem to be quite what I'm getting from my tickering with the sensor. Whatever I do with the sensor the analogRead function returns something between 10 and 20 with "Serial.println(analogRead(IR_RANGE_PIN), DEC);" I would normally expect something between 0 and much more because the graph peeks at 2.75V, yet I can't achieve anything remotely close to that.

4

Yep by taking a look at some guy, I have the exact same setup yet I don't values above 20. I think my sensor is broken

5

"Serial.println(analogRead(IR_RANGE_PIN), DEC);"
So not the same code.
Post it. According the forum guidelines (with code tags).
And add a 'real' picture of the setup.
Without all the information it's hard to help you.
Leo..