Step 1: Parts List
-22 awg solid core wire
-2 1kΩ resistors
-9V to 5V voltage regulator
-graphite pencil and paper
-audio cable and speakers or headphones
If you're new to electronics or working with breadboards, check these out:
ICs, 555: https://www.instructables.com/id/Know-Your-IC-555-Timers/
Breadboards video: https://www.instructables.com/id/Breadboard-Basics/
Breadboards how-to: http://www.techdose.com/electronics/How-to-Use-Solderless-Breadboards/252/page1.html
Step 2: BUILDING THE CIRCUIT
This IC is an astable oscillator, which means it produces square waves. At high enough frequencies (anywhere above 20Hz), those waves can be turned into audio!
Step 3: BUILDING AND CONNECTING THE GRAPHITE MIXER
You can connect the final wire (red) to either of two pins for different results. If you connect the wire to pin 5, the circuit will always play a constant tone. If you connect the wire to pin 7, the circuit only plays a tone when the free end of the wire is in contact with the graphite. The pin 7 option is usually more practical, unless you want a pedal tone on your synth.
Step 4: POWERING YOUR CIRCUIT/MAKING SOUND
To get sound, make sure your mixer is connected to a speaker through the audio jack. If you don’t have this, headphones work just fine. You will have to press down on the exposed wire (the red one) so that the exposed tip connects with the graphite. The graphite acts as a variable resistor. As you change the distance between the ground wire and your red control wire, you change the resistance on that pin (5 or 7), which changes the pitch of the sound!