Re: Re: Would Water Surface Reflect IR?

[Dave Ward <DFHWukha@xxxxxxxxx>]

Water will reflect IR,  ripples on the surface would also scatter the
return signal, so it really depends how sensitive the Sharp sensor is.
Have you asked on one of the robotics forums or even the store if they
could test it?
You could also try a simple test.

Point a TV remote at a bowl of water and view the result with a digital
camera.

>From the datasheet the wavelength (λ) = 850 nm ±
70 nm which is the same
as a TV remote IR LED.

Most digital cameras, CCTV, Mobile phones, etc are still reasonably
sensitive to IR at this wavelength even if they have an IR cut filter.

HTH

Dave







Chris Hunter wrote:
> Hmm ... not sure ...
>
> the following may help, a little :
>
> http://en.wikipedia.org/wiki/Infrared
>
> Chris
>
>
>
> On 30 Apr 2007, at 10:56, lexfordparc wrote:
>
>> Hi Chris,
>>
>> The unit I have my eye on for the IR version of distance measuring
is
>> the Sharp GP2Y0A02YK:
>>
>> http://www.active-robots.com/products/sensors/sharp/gp2y0a02yk.pdf
>>
>> However, Karam also suggested it maybe possible to add some tubing
on
>> the end of the ultrasonic sensor to absorb the ultrasound emition
and
>> recpetion from the wall.
>>
>> Paul
>>
>> --- In ukha_d@xxxxxxx, Chris Hunter <cjhunter@...> wrote:
>>> There's IR & there's IR ... depends on frequency ... water
vapour
>>> absorbs most IR ... not sure about liquid water ... 'would
check
>>> Wikipedia, etc ... but Google's not responding at the moment
... !
>>>
>>
>>
>>
>>
>>
>>
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