Component stock

I have a pretty good supply of electronics I keep in stock... I have an array of microcontrollers, an FPGA dev board, all of the transistors, resistors, diodes you can shake a stick at. Common ICs that you'd use for the normal run-of-the-mill circuits. Hell, even non-run-of-the-mill stuff too like a collection of high bandwidth transimpedance amplifiers (TIA).But I go down to the shop to find either a photodiode or a phototransistor and I come up empty. :-(Why am I looking for a relatively fast photodetector? To reverse engineer a really cool headlamp from Petzl: the Reactik+. It adjusts to what you're looking at almost like magic. But I think I've determined the magic completely: it runs kind of like an over-simplified lock-in amplifier. But I need to be able to examine the light in high speed to get a handle on it.Alas...At least the TIA will come in handy for the photodiode. Wire that puppy up and probe it with the scope... good times.Now to think what other stuff I need in the storeroom when I put together an order tonight.