Thanks to my buddy Tom I have discovered Transimpedance Amplifiers. These chips wrap up the entire functionality of the circuit I was trying to mimic. They work great. A little expensive at $4.50 but worth it. I'm using TI's OPA380A. Digi-Key has them in single quantities. So, I've now quite successfully breadboarded my IR detection circuit and am ready to commit the design to DipTrace.
I learned a little something about FETs tonight. After getting the detector working well, I tried to up the amperage on my LEDs. At some point I pulled the wire off the gate of the FET to connect it in a different way to the MCU. Suddenly my invisible light LEDs became visible light LEDS. Then they turned black and smoke actually escaped the plastic housing! Apparently I pulled the FET just at the moment the gate was charged. Since the gate is a kind of capacitor, it had no way to discharge once I pulled the wire and thus the FET remained on long past 10us. Since the LEDs are only rated for that amperage for 10us at a time, they promptly smoked. Lesson learned! Anyway the 1.32 amps should be fine. I'll just go with that.
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