Anand Dhuru wrote:
> I'm trying to build an IR based object detector based on the 16F628.
> The prototype works fine just the way I want it to, but I have run
> into a problem in encasing the unit.
>
> Since it works on detecting IR reflected from an object, the
> transmitter LED and the receiver IR module are both to be mounted
> within the same case. To reduce the chances of the transmitted IR
> being directly incident on the receiver, I've put a piece of heat
> shrinkable tube on the LED, exposing just the tip. This works pretty
> well as a shield.
>
> Now, if I try to mount the unit in a cabinet, the plastic/acrylic
> bezel reflects the IR, enough to trigger the detector. Is there any
> material that is *much* more transparent to IR that I could use as a
> bezel? The only other alternate seems to be to keep the two exposed,
> without using a bezel on the housing.
>
> Do any of you folks have a suggestion?
>
> Regards,
>
> Anand Dhuru


Separated compartments for transmitter and receiver, with independent bezel
for each one?
Two holes into the case, small IR transparent disks inserted into each
hole?

Are you sure you need just one lens in front of the TX/RX pair?

Wagner

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