How's about playing with some random numbers where a player press a button and his lucky number is displayed on screen?? Funny..right? This is possible by using CD4026 IC and 555 timer and a couple of resistors and capacitors and switches. This is very cheap and a good project for beginners. I made this project so that we can play a simple but a good time passing number game and the whole thing is super cheap. I made one ,showing numbers from 0-9 .You can extend it to infinity, I will explain this in the upcoming steps .So let's build it..

Step 1: Parts Required

1. 555 timer 1pc

2. CD4026 1pc

3. 8pin and 16pin IC socket (optional)

3. 3 100K resistor

4. 3 10uF polarised capacitor

5. 1pc 1nF(102) non polar capacitor

6. 1 common cathode 7 segment display (example- FND560)

7 2 Pushbuttons

8. 100K variable resistor(Code-104) 1pc

9. 6-9V battery with clip

10. breadboard and solder kits

11. Multimeter

Step 2: Working Principle and Testing on Breadboard

This is a game for two players. Player 1 presses the START button. This resets the 4026 counter chip and starts the 555 oscillator. The 555 produces 10 pulses per second and these are counted by the 4026 chip and displayed on the 7-Segment display. The second player is required to press the STOP button. This freezes the display by activating the Clock Inhibit line of the 4026 (pin 2).Two time-delay circuits are included. The first activates the 555 by charging a 10u electrolytic and at the same time delivering a (high) pulse to the 4026 chip to reset it. The second timer freezes the count on the display (by raising the voltage on pin 2) so it can be read.

Now I have made one that shows only from 0-9. You can extend it to infinite number. You just need to connect the carry out(pin 5) of CD4026 to Clock In(pin 1) of the next CD4026 and the same process repeats for adding more digits.Check the block diagram shown above.

You can check datasheet of both 555 and 4026 for more info.

I have build this on breadboard as per the above schematic.

You must set the variable resistor to a particular value for making the time delay. I used multimeter for checking that resistance.I took about 1.1kohm. You can change it slowly and can increase or decrease the delay using a screwdriver.

If it is not working and rebuild again. Give a good fresh supply 6-9V else it won't work properly.

Step 3: Soldering All Components

Now if you wish to make this permanent then you could try to build on perfboard.

Get your solder kits, keep the schematic beside you, take your patience and start soldering carefully. You might need extra hookup wires For it. Don't make the IC too hot. You might use a 8-pin and 16-pin socket.

So now everything is done and connect battery and start playing.....