Algodoo

This is an unusual application for an optical switch, but I can see how it might work if you can get the light from the LED to reflect off the mylar film and back into the phototransistor. If that's a 10K resistor in series with the LED, then the LED might be too dim to produce enough light. 10K at 5 volts gives only about 0.5 mA source current for the LED. Normally, they like to see at least a few mA (typically around 10) when operated as an optical switch. And yes, you would need a pullup resistor so that the phototransistor can conduct, and a blocking capacitor on the input to the amplifier. I played around with similar circuits in my younger days when I spent more time building electronic gadgets.

CORRECTION: I adjusted my monitor, and now that resistor looks to be 1k, which should work just fine (Colors are not accurate on my crappy monitor).

I used to play around with electronics like I play with Algodoo now. I started out with a Radio Shack 150 in 1 kit. One of my more ambitious projects (not made with the kit) was to design and build a sampling oscilloscope that would connect to a TV's antenna terminals and display the waveform on the TV.

Prior to the pill bottle mic experiment I had used a toilet paper roll and aluminum foil to make a kazoo that you would talk into. Sunlight would reflect off the aluminum foil onto a solar cell connected to the volume control wiper of a small transistor radio. It worked surprisingly well. The experiment was modeled after one performed by Alexander Graham Bell.

Fun stuff!

I can say that i dont understand abdolutly nothing