An infrared diode in conjunction with an infrared photo-transistor can
easily perform this reflective sensing task at a distance of 12" to 16".

The prepackaged infrared reflective sensors will probably not work at a
distance of 12".

Another possibility that I use is the TAOS (WWW.TAOSINC.COM) Light to
Frequency and Light to Voltage converters.
These light to V or F converters interface well with microcontrollers and
provide an output that is proportional and linear to the light or infrared
intensity received.
The TAOS light to V or F converters are available for ambient light
(300nm-700nm) sensing and infrared (800nm-1,100nm) sensing.
TAOS also has an evaluation kit that includes a microcontroller, LCD
display, ambient light sensor, infrared sensor and light sources.

Sincerely,
Ned Seith
Nedtronics
59 3rd Street
Gilroy, CA 95020
(408) 842-0858
ned@nedtron.com
 >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
At 10:06 AM 8/24/01 -0600, you wrote:
>I am trying to decide if I can use an IR setup to determine if something is
>in range.  I could use ultrasonic, but I wondered if IR might be easier.
>All I want is PIC watching the inputs and if the box is moved within a
>certain range (12"-16") turn on an LED.  Simple in concept....
>
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