Flashing Lights Using the NE555

The flashing light circuit uses the NE555 in astable mode. This mode is also known as the oscillation mode, it creates continuous square waves. Square waves is a type of waveform that alternates between logic 1 (high) and logic 0 (low). It is known as the square wave because of the square shape it produces when viewed on an oscilloscope. This square wave allows for the light to alternate between on and off.

Resistors: 10kΩ, 470Ω

LED: Standard Indicator LEDs (3/5mm)

Capacitor: 10uF

Potentiometer: 250 kΩ

IC: NE555

miscellaneous: Breadboard, single thread wires, battery pack 9V

(Extension): soldering iron, solderer, matrix board.

Before we start configuring the circuit in real life, we must model the circuit online, it is easier to prototype the circuit using online software because tweaking the circuit could be done trouble free. The recommended software for this circuit is Tinkercad. Alternatively Autodesk Eagle or Fritzing.

Click the blue create button on the top right, remember to create a circuit not a 3D design. Every component will appear when typed into the bar on the top left, Tinkercad uses a 840 pin general sized breadboard. Clicking on a component will initiate a pop-up screen. Enter the specified value for each component.

To keep the NE555 on astable mode the following connections must be made.

Power Supply:

Connect Vcc (Pin 8) to the positive power supply.

Connect Ground (Pin 1) to the negative power supply (ground).

Resistors:

Connect resistor R1 between Vcc (Pin 8) and Discharge (Pin 7).

Connect resistor R2 between Discharge (Pin 7) and Threshold (Pin 6).

Capacitor:

Connect capacitor C1 between Threshold (Pin 6) / Trigger (Pin 2) and Ground (Pin 1).

Connections:

Connect Threshold (Pin 6) and Trigger (Pin 2) together.

Connect Output (Pin 3) to the load (LED).

Leave Reset (Pin 4) connected to Vcc (Pin 8) or ensure it is not grounded to keep the IC active.

The hand drawn schematic legend:

The positive power is connected to 8pin (orange)

The negative power is connect from 1pin (blue)

R1 and R2 is labeled

R2 is a variable resistor

6pin and 2 pin is connected (green)

4pin and 8pin is connected (green)

3pin is connected to the lamp which is than connected to ground (green)

C1 is labeled

C1 is a polarised capacitor

Once we are finished modelling the circuit online, we can move onto the breadboard. It is recommended to exactly copy your working breadboard from Tinkercad. In this picture I used a breadboard power supply module, conveniently it bridges the positive and negative to both sides of the breadboard. A battery would work the same but you would have to bridge the positive and negative to both sides of the breadboard manually. The knob on the potentiometer might respond differently to the Tinkercad, tweak to get the best range. Once this is working you are technically done, if you dont want to work further on this you can skip step 3.

We are now ready to create the functioning machine on the matrix board. Prepare a matrix board and soldering setup, most matrix boards will have similar connections to a breadboard. To check, flip the matrix board and compare to a breadboard. Matrix boards cam come in many different shapes and sizes. If they are not similar, critical thinking skills are required. In the picture only the positive was bridged because there was no negative connections on the other side. Once finished connect to any power source with dual power sources. It rarely works on the first try, things to check are: excessive soldering iron creating short circuits, positive and negative are ordered correctly, components are layed out correctly, potentiometer is dialed to the correct resistance.

If it works, you are done! you finished this intractable. Enjoy your flashing light by adjusting the frequency. This is one of the easiest application of the NE555. I hope this instructable helped you. This was my first intractable.

Please comment if there is any mistakes or anything I missed.