sharp IR 250cm distance

[manut]

hi everybody,
I read on this page http://www.active-robots.com/products/sensors/sensors-sharp.shtml that the SHARP GP2Y0A02YK Distance Measuring Sensor could accurately determines range to target between 20cm and 150cm, but it's written below "Can be used as a proximity detector to detect objects between 0cm and 250cm"... so, what does it mean?it measures between 20 and 150 or 0 and 250? or is there a trickto convert the 20-->150 into 0-->250?
I'm going to use it with an arduino board.
Thanx

[Soeren]

Hi,

[...] but it's written below "Can be used as a proximity detector to detect objects between 0cm and 250cm"... so, what does it mean?

You're asking us what they mean?
We could try some wild guesses (but I don't believe it will reach out to 2.5m, for a reliable detect/no-detect), but you really ought to ask them.

[chuckdaball]

http://www.societyofrobots.com/sensors_sharpirrange.shtml

[waltr]

The Data Sheet for the sensor from Sharp is the last word so read that. Figure 3 shows the voltage for distance and only goes to 150 cm.

The Active Robots blurb could easily be a typo.

[Soeren]

Hi,

The Active Robots blurb could easily be a typo.

I doubt it. This is repeated for each of the range sensors, eg. the GP2D12

Infrared distance measuring sensor accurately determines range to target between 10cm and 80cm.
[...]
Can be used as a proximity detector to detect objects between 0cm and 130cm.

The GP2D120

Accurately determines range to target between  4cm and 30cm.
[...]
Can be used as a proximity detector to detect objects between 0cm and 50cm.

The GP2Y0A21YK

Infrared distance measuring sensor accurately determines range to target between 10cm and 80cm.
[...]
Can be used as a proximity detector to detect objects between 0cm and 130cm.

All sixty-some% longer range that should show something above noise

They can all detect down to 0cm (just not give the correct distance), but I doubt that there will be useful proximity data at 250cm, as the beam will have spread so much that random ground reflections will come into play and would probably mean a varying signal even without an obstacle - for a small slow-ish 'bot, 2.5m is not what I'd call proximity anyway.