David Peins, I am continuing to learn about surface mounted sensors.
I've observed that this circuit (which contains an SMD phototransistor) is different from the one that I created with a photo-resistor.
1. The LED in this circuit turns off in bright light, while the LED in my other circuit was programmed to turn on when it's dark.
2. The SMD components in this circuit are more elegant, but are trickier to work with.
Try to get this circuit to work with an Attiny85.
Figure out a practical way to use this in a project