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 π

Concept:

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 letβs consider the number 24

Number 2 4 β 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).

Design:

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dataβ 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Qβ goes HIGH.

BCD to 7-SEGMENT:

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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### 6 Responses to “Mathemagic β Mind Reader”

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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. Diego says:

4013*

4. Vincci says:

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

5. Vincci says:

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

6. Annis says:

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