Got hold of a Velleman kit for a Flashing LED set. The kit is essentially an astable multivibrator.

The kit in it self is simple, and a great way for me to learn basic soldering and so on. But the kit lacks in way of usability, and I have a science project coming up with soundwaves. So it would be a great way to show some basic frequency changes in sound and how it affects the audible sound.

First of all, the diodes blink at a very slow rate. This frequency is far beyond the humans perception range. The problem is easily solved with two new 100n capacitors instead of the standard 10u which allow for a much higher frequency range for the two trimmers.

Schematics:

Finished product: