Step #1: Gather Your Parts, Install ICs and Hookup WirePrevNext
- Gather together the required parts along with the breadboard.
- Breadboards have positive and negative power rails running along the top and bottom. They are typically marked with a red line for positive (+) and blue (or black) line for negative (-). When you power the board, you can connect a 5-6v battery (or DC power supply) with positive and negative connected to the respective rails.
- Our first task is to place the 3 ICs (integrated circuits) in line, and be sure they're in the correct orientation. Using the 22AWG jumper wire, connect power (- is black, + is red). You can see that I've connected to the two power rails on either side of the breadboard.
- The next step is to add the additional lines to power and ground (third image), again using red for positive, and black for negative.
Step #2: Install Buttons, Switch, and ResistorsPrevNext
- Connect the three 10KΩ 1/4 watt resistors, the SPDT toggle switch (white wires), and 2 push buttons (yellow wires).
- Add two wires to connect the middle 10KΩ resistor to the 555 timers. The longer wire will connect to the first 555 IC, and the shorter wire will jump this connection to the second 555 IC (image 2, yellow wires).
- Seen in image 3, we've connected the push buttons to the OR-gate inputs via the white wires.
Step #3: Add Capacitors and Make More Wire ConnectionsPrevNext
- Continue adding more connections (yellow wires) between the OR-gates on the logic chip (image 1).
- In image 2, we've added the two 0.01μF ceramic disc capacitors - these go from the lower negative power rail, and pin 2 of each 555 timer.
- In the final picture, we hooked up two white wires to connect the ceramic disc caps back to the logic chip.
Step #4: Add LEDs and Finish Your ConnectionsPrevNext
- Now get out your LEDs! The longer leg of the LED is the positive (anode) leg - the shorter leg is negative (cathode). In our next step, we'll connect the anode to the ICs output, while the cathode will connect to a 330Ω resistor and then on to ground.
- Place the two red indicator LEDs and 330Ω resistors. Finally wire the LEDs to the 555 ICs with 2 red wires (image 1).
- Our last connections! Two black wires feed the signal from the LEDs back into the OR-gate logic chip (image 2).
- That's it! Connect up a 5-6v power supply to the breadboard power rails and test it out. Here's a video showing how the circuit operates: http://www.youtube.com/watch?v=pQC6SLnlc...
Step #5: Addendum: The SchematicPrevNext
Here is the full schematic for the game show buttons.