-Two 9-Volt batteries -Four 100 ohm resistors -One LM741 op amp -One 1K ohm resistor (1000 ohm) -One .1 uF capacitor (any type) -Two 4.7K ohm resistors (4700 ohm) -Two 1N914 switching diodes -One red LED -A project case -Two mono 1/4" (6.3mm) female jacks -One DPDT switch (two way 6 pin) -One on/off switch -Perf board (with copper rings on bottom) -Thin wire -Soldering iron -Solder -Two 9 volt battery holders (just take the tops off of two dead 9 volt batteries, the batteries will fit into them perfectly)
I also suggest getting a solder sucker and some soldering braid. Very useful stuff!
All of the above can be purchased at Radio Shack, so no need to hunt around. The total price should be around $10, unless you need a soldering iron. Those usually run about $10-$20.