Roulette Table (555 Timer Project)

In this project you will be constructing a roulette table. This table will be a series of 10 LED light bulbs which will flash continously around then come slowly to a stop at one of the LEDs. I will be constructing this project on a bread board and will not be constructing this on a perfiorated board with soder, but you are more than welcome to do so and follow the same procedures.

You will need wires, 9 volt battery or Power Source, 555 timer, CD 4017, 10 LED lights, resistors (10M, 4M7, 3M3, 10k, 470), BC 557 transistor, 1 uF polarized capacitor, and 100 nF capacitor. If you are looking to soder and make this circuit on a perforated board you will need the necessary supplies to do so.

In this step I will be testing/measureing all the components of this circuit with a multimeter to be sure that all the values are approximately close to what the said to be values are or if the equipment is working properly. For an example to test a battery say that it is close to being dead and instead of measuring 9 volts it measures 5 volts then you would need to replace that battery. Be sure to do this with all resistors, capacitors, and the battery/power source. Next to test if the LEDs are working properly I would set up a small circuit that consits of a power source and a resistor in series with the LED and make sure that the LED is oriented in the correct way and should go from anode to cathode. Make sure all LEDs are working properly and then you sould be good to continue. Note: We had not tested all the components such as the 555, CD4017, and neither the transistor and will be delt with later in the process and if needed switching components should be easy.

In this step you will construct the circuit as the above diagram shows.

-Some things that you should look for and be careful of:

Make sure the LEDs are pointing in the right direction. Remember the current flows from anode to cathode.

Be sure to have the polarized Capacitor oriented in the right direction.

-Helpful Hints to Construct the CIrcuit:

When constructing this circuit I prefer to work from one side of the power source/battery and work my way around the circuit until I reach the other end of the power source/battery just to make sure everything is in order.

Look at the highlighted regions of the circuit diagram.

The blue region:

This reigion includes the 555 timer and is responsible for producing a wave function that will drive the decade counter (CD4017) to light up the LEDs at a specific frequency. Once the button is released it will also produce a wavefunction that slowly reduces its frequency until it reaches 0 Hz and there will only be one LED lit. To test if this part of the circuit works properly we can attach an ocsilloscope to the 3 pin on the 555 timer and look as the frequency produced and then even see it decay once the button is released. The frequency produced should be around 8-10 Hz and slowly decay to 0 Hz

The Red region:

This region holds the decade counter (CD4017) which is responsible for taking an input frequnecy and using that to light up the LEDs in order. To test if this part of the circuit is working properly we can attach the 14 pin on the CD4017 to a frequency generator and you will see the LEDs light up in order over and over again. Only use a frequncy no higher than 12 Hz to simulate the frequncy from the blue part of the circuit. As you may see in my project my CD4017 was not working properly. Some of the pins were not working correctly and therefore not lighting up some of the LEDs. The general concept of the project was understood and most of the LEDs were working properly. I did not have a replacement CD4017 so I had this same one through the entirety of the project.

In this step you can also diagnose problems possibly with the transistor, 555, and CD4017. If a problem does occur just replace the necessary parts.

The next step in this process before obtaining a final product is you must test the circuit (Obviously). If all is working well then congratulations you now have a working Roulette Game.