Bob,

        You will be hard pressed to measure the TOF of pulse light with a 20
Mhz Microprocessor.  If you truly want to do TOF distance measuring with
light you will need some sort of Mikelson Inferometer setup, I probably
spelled that wrong but I think everyone did this experiment in the college
Physics Lab.

        A much better method is to use some sort of reflected angle type
scheme where the laser is reflected back to a sensor and the angle between
them is used to determine the distance.  Something like this.


 >
   >
     >
   >
 >

        I read an article in Circuit Cellar where a guy this using a CCD
camera so he didn't have to move the detector as you would with a standard
photo diode. It was pretty neat I thought.

Ben,

At 10:30 PM 2/26/97 -0700, Bob Newhart wrote:
>Hi,
>        I'm enrolled in a university microcontroller class and am considering
>making an inexpensive laser surface-mapper for my final project.  I was
>wondering whether anyone knows of a single chip to which I can connect a
>laser diode and a photodector, then interface to a PIC in order to
>measure range.  Ideally, all this chip would need to do is pulse the
>laser and measure return time to the photesensor, then multiply by the
>speed of light and output the result as a voltage.  However, I'm open to
>suggestions.
>
>I've been searching the net for about three hours, but everything I can
>find is either prefab or more sensitive (and expensive!) than I need.
>Thanks in advance.
>
>Jason Harris
>
Ben Wirz                For Microchip PIC Products including the Simm Stick
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