Digest Number 1085
Archiver
Posts: 46,084
I don't agree with your premise that you can't measure the amount of light
received with an IR photodetector. Just run the output of a Sharp QRB1134
detector though an AtoD convertor (needs a properly sized pullup to "tune"
its sensitivity) and you can detect a full black/white range of reflected
light, so why not transmitted light? The data sheet on this device shows that
it is not strictly an on/off device.
I'm doing this right now with a line follower, not with a Stamp, but with a
PIC '877.
Larry
In a message dated 2/15/02 5:56:37 PM Pacific Standard Time,
basicstamps@yahoogroups.com writes:
>
> If you transmit an IR beam to an IR detector, the detector receives it or
> it
> doesn't. In other words, it is an on-off situation. You cannot measure
> the
> "amount" of IR transmitted through a medium using the Stamp and a detector.
>
> There probably other more sophisticated methods but using the Stamp is not
> one of them. If you wanted to place your detector close to your liquid
> medium, then move it away until you lose the IR signal you could probably
> correlate distance to opacity or oabsorption, but that is a tough way to
> go.
>
>
[noparse][[/noparse]Non-text portions of this message have been removed]
received with an IR photodetector. Just run the output of a Sharp QRB1134
detector though an AtoD convertor (needs a properly sized pullup to "tune"
its sensitivity) and you can detect a full black/white range of reflected
light, so why not transmitted light? The data sheet on this device shows that
it is not strictly an on/off device.
I'm doing this right now with a line follower, not with a Stamp, but with a
PIC '877.
Larry
In a message dated 2/15/02 5:56:37 PM Pacific Standard Time,
basicstamps@yahoogroups.com writes:
>
> If you transmit an IR beam to an IR detector, the detector receives it or
> it
> doesn't. In other words, it is an on-off situation. You cannot measure
> the
> "amount" of IR transmitted through a medium using the Stamp and a detector.
>
> There probably other more sophisticated methods but using the Stamp is not
> one of them. If you wanted to place your detector close to your liquid
> medium, then move it away until you lose the IR signal you could probably
> correlate distance to opacity or oabsorption, but that is a tough way to
> go.
>
>
[noparse][[/noparse]Non-text portions of this message have been removed]