Monday, December 03, 2012

BASIC ELECTRONICS PROJECT 1- 7 SEGMENT DISPLAY COUNTER / INCOMING PERSON COUNTER






Hiii…….friends this time I am here with a very interesting projects for those who have just started with electronics. With this project we can display 0-9 digits on the 7 segment and we can count the no of persons entering in the room.

Circuit diagram


Here a counter IC 7490 is  used along with BCD to 7 segment decoder IC 7447. The function of 7490 is to provide the counting value and decoder IC is decoding that value to 7 segment output . Every time when you will push the switch the clock of IC7490 will be triggered and as a result count will increase by 1 . Hence with this simple project we can display numbers 0 to 9 on seven segment display just by pressing switch. It’s a very easy circuit and you can easily implement it on a general purpose PCB.


NOW ITS TIME TO MAKE USE OF THIS CIRCUIT IN COUNTING THE NUMBER OF PERSONS ENTERING IN THE ROOM...... LETS SEE HOW….??

So  instead of using switch we will use LDR here , we will place LDR at the entry door in such a manner that the shadow of the entering person should fall directly on LDR , when shadow will fall on LDR clock of IC 7490 will be triggered and as a result the count will increase by one. Circuit wilh some small changes  is as shown. Variable resistor is used to adjust the resistance to synchronize the light intensity for better results.



COMPONENT REQUIRED


U1                  IC7490

U2                  IC 7447

R1-R7            RESISTORS 330R x7

SEVEN SEGMENT DISPLAY( common anode)

Push button

POWER SUPPLY ( 5 to9 V)

LDR and VARIABLE RESISTOR



I hope this was a interesting project and u can use it as your school project or mini project as well.  In case of any doubt, question or critical view just leave a comment.

         THNX…J

20 comments:

  1. how can your dec counter function when you only hve 1 clock input??

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    Replies
    1. Hi,, friend I am not getting your question properly, will you please make it some more clear.??

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    2. hi.. what do you mean RV1 in the circuit diagram? and what the arrows mean in the 1k resistor?.. sory. i dont understand that part.. im a newbee...really need it...thanks.

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    3. hi.. what do you mean RV1 in the circuit diagram? and what the arrows mean in the 1k resistor?.. sorry, i dont understand that part.. im a newbee...i actually tried your circuit but it doesnt work...

      really need it .....thanks

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    4. Hi, Chang.........RV1 is representing variable resistor of 1k as shown, and the arrow is representing middle pin of variable resistor....:)

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  2. Replies
    1. Hi Biasa .......u dnt need any coding for this project just implement this simple circuit and it will start working.......:)

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    2. and may be there is any mistake because i hv tried this circuit and its working fine, use variable resistor properly.......it will definitely work...:)

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  3. What if I wan to reset counter to '0' , how can I do it? thks

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    1. here we are using 7490 IC which will count from 0-9 and at tenth count it will automatically reset to 0.

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  4. What if we would like to increase the display for two digit or three digit numbers. Is that possible in the above circuit?

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  5. Can we increase the number of 7 segment display for two or three digit numbers? is it possible in the above circuit?

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    Replies
    1. yes....of course !! using multiplexed seven segment driver ICs like MAX6950 or MAX6951....it is easily possible....:)

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    2. You can use two 4026 decade counter chips to accomplish this very easy. Your circuit would then only consist of 2 4026 chips, 2 seven seg displays, and 2 tact switches (one for count and one for reset. A few 1k resistors and a 100uf smoothing cap. I would add the schematic but don't see an option to do so. Feel free to email george3453@google.com.

      Have fun,

      George

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    3. Hey George Foster!
      Will you plz sned me your 4026 decade counter circuit that you have designed?
      my email is usamao45@yahoo.com

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  6. thx for the circuit...it works well~can u show us how to build a timer circuit using four 7-segment display?

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  7. Can I use an IR led (in the place of torch) and an IR Sensor in the place of LDR

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  8. Can I change the torch with the IR Led and The LDR with LDR sensor

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  9. How to use the Variable resistor correctly?

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  10. How to use the variable resistor?

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