Step 1: Parts List
-3 alligator clips
-22 awg solid core wire
-7805, Voltage Regulator
-2 Synchronous 4-bit counters (74HC193N)
-4 1kΩ resistors
-1 1µF capacitor
-speaker and audio cable or headphones
-graphite pencil and paper
Step 2: BUILDING THE TIMER CIRCUIT
Step 3: BUILDING THE 4-BIT COUNTERS
Build another 4-bit counter the same way. Instead of connecting the input at pin 5 to the 7555, connect it to pin 7 of the previous counter. The yellow wires in the picture are running the output to a different spot on the board for easier access.
Step 4: BUILDING THE GRAPHITE MIXER
Connect one end of the graphite to the tip of the audio/headphone jack via an alligator clip. This is the red clip in the picture. Connect the other end to the breadboard’s ground (white clip). Connect the sleeve of the jack also to the breadboard’s ground (black clip). Connect the 8 outputs from the board to the mixer via long wires with exposed ends.