Mathemagic – Mind Reader

This is a simple application where in you think of a number from 1-99 in your mind and then the machine tells you what it is !

All you have to do is, think of a number and say if it is greyed out in the series of cards shown.

Before we step into any detail, Watch the video πŸ™‚



The concept behind this is a BCD to 7-Segment decoder(IC7447). The unit and tens place of the number are in BCD. For example let’s consider the number 24

Number 2 4 – This in BCD would be 0010 0100. Thus this number would be found in sheet3 and sheet6. When you press these corresponding switches, the number would come up in the 7-segment display.

The switches used here are momentary push switches. When the switches are pressed, we would need it to be giving a constant HIGH. For this we use D Flip Flop (IC4013).


Switch Configuration:

The flip flop is used to sense the switch input and it goes high permanently (until the reset button is pressed). For this we connect the β€˜data’ pin to VCC and the clock pin to the switch output. As the flip flop is positive edge triggered, this pin is pulled low with a resister and the switch is connected to VCC. When the switch is pressed, the pin is pulled up to VCC and this triggers the flip flop, thus the output pin β€˜Q’ goes HIGH.


IC7447 is used to drive the 7Segment. This circuit uses a common anode 7-Segment, the output of flip flops are directly fed to the BCD inputs of the 7segment driver.

Circuit Diagram:

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Let me know your comments πŸ™‚

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6 Responses to “Mathemagic – Mind Reader”

  1. […] entries Tic Tac Toe won a first place and Mathemagic won a third place […]

  2. Diego says:

    How much volts do you use to power these? And also, can we use CD3013BE instead? And what values of resistor do you use?

  3. Vincci says:

    What is the values of volt you use? And what is the values of resistor? Thanks

  4. Vincci says:

    What are the values of volt you use? And what are the values of resistor?

  5. Annis says:

    I go to see each day a few websites and blogs to read posts, however this blog presents feature based articles.

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