Hey, am making a project which senses an object passing through a gate and counts the number (and displays it). For that i am using a 4-bit ripple counter IC (74LS293). I am displaying with 7-segment display.

How can i drive two 7-segments using a single 7448 decoder?

 

Can you supply us with a schematic diagram of your circuit at this point?

hgmjr

 

You should be able to multiplex the 7448. I'm amazed you have one. Original TTL IC's are hard to come by.

Multiplexing is lots more trouble than just using another BCD-to-seven segment decoder.

 

See the attached schematic. I drew this up quite a while ago when I was building a coil winder, to keep track of the number of turns; it wasn't really meant for general publication or it would be more neat. It uses a Hall-effect device that senses when the shaft of the winder makes a complete turn.

But of interest to you is the use of the CMOS 4553 and 4543 devices; one is a 3-digit BCD counter/mux, the other is the BCD to 7-segment driver. Pretty handy pair of CMOS IC's, and you can get them just about anywhere still. This just gives you a general idea on how to hook them up to drive three 7-segment LEDs.

Note that Vdd and ground pins are not shown, nor are the 0.1uF bypass caps.
Note that the 7-segment displays are common anode.

Where on earth did you find the 7448?

 

tell me all i need to know about a two digit counter which senses an object passing through a gate and counts the number (and displays it).

 

tell me all i need to know about a two digit counter which senses an object passing through a gate and counts the number (and displays it).

See the circuit I posted?
Use it.

 

can u post the program used

 

can u post the program used

The program that I used to create the schematic is Cadsoft DE's Eagle Layout Editor.

You can download the current freeware version from Cadsoft's website:
http://www.cadsoft.de/
The freeware version is limited to single-page schematics, two layers in a board, and the size of the board is limited to about 3"x4". It is still quite useful, even with those limitations.

It is confusing at first. Going through the tutorial is highly recommended.

Here is another tutorial:
http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=57&sipp=1&page=8
You may actually wish to start with this one.

 

can u post the program used

If you are referring to the use of a program for the circuit, You do realize that the circuit does not use a microcontroller, right?

hgmjr

 

From a PM:

Hi
i m the mechatronics student n goning to start my final year project can u give me some projects.
mail me plz at this id
(E-mail address omitted)

Navid,

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