Actually, you have to sample at a rate much faster than the data it you want to establish good bit framing. UARTs often over sample at 16 times the bit rate to get the framing right. No need to get bogged down in that for now.

I might be able to run that Radio Shack part number down online. Personally, I would avoid op-amps.

The detector output is the key. It may have normal digital output levels. You might be able to connect it directly to the micro our you might put a simple schmitt triggered buffer between them to clean up the signal for the micro. A 74HST14 is a hex (6 pack) Schmitt inverter that Radio Shack also sells. You would just run the detector signal into one inverter and then into another before running it to the micro. This would double invert which would bring it back to the same level the detector outputs. Often inversions can be corrected via software.

Don't buy that 14 pin dip chip until we confirm the type of detector you're using.

I'll look online for that detector part or drop into a store during lunch tomrrow.

aka j