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How to make a 7 segment LED display?

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KrazyTurboTsi

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display de siete segmentos hcf4511

How would I go about making a 7 segment LED display read off the numbers 1,2,3 and 4, when +12v is supplied from one of the 4 switches. While making shure that each circut is kept completely sepearate. I also have limited space where this display needs to go. Any Ideas?
 

IanP

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hcf4511 i use

Take 4 optocouplers and connect the diode sides to 4 switches and related 0Vs (through resistors) ..
These optocouplers will provide the required separation.
The other sides of optocouplers have transistors which collectors can be connected through a network of diodes to cathodes of 7-segment common anode LED displays (Emitters of these transistors should be connected to 0V) ..
For example, if you need to display "1" you will connect two diodes to segments B and C ..
Probably the same can be realized with 4 minature RLYs ..

Regards,
IanP
 

KrazyTurboTsi

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display hcf4511

so ive gotta drop the voltage to 0v with resistors, and connect a network of diodes? I understand this somewhat, but am partially lost. Any part numbers/datasheets I can look at of these optocouplers. And what is a "collector"? Maybe something else so i can draw it up on circutmaker and see exactly what I need to do and run simulations.
 

IanP

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Re: 7 Segmet LED Display

Have a look in the attached files ..

There are two examples on how to display numbers on 7-segment LEDs: one is activated by an optocoupler, the other one by a relay ..
The third picture shows how to use diodes in 4-in-1 combination and direct drive from voltages V1 - V4 through transistors ..

Regards,
IanP
 

afti_khan

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Re: 7 Segmet LED Display

check "8051 uC" by scott mackenzie
 

crowinu

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Re: 7 Segmet LED Display

KrazyTurboTsi said:
How would I go about making a 7 segment LED display read off the numbers 1,2,3 and 4, when +12v is supplied from one of the 4 switches. While making shure that each circut is kept completely sepearate. I also have limited space where this display needs to go. Any Ideas?

you can also use a bcd/hex to 7segment display decoder instead of transistors.
 

albert22

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Re: 7 Segmet LED Display

The solution from Ianp is very simple and effective. However if more than one of the input signals is active you will get a wrong display. Because the segments of the various inputs will be added.
Following the optocouplers. You can use a "priority encoder" like the CD4532 followed by a BCD to 7-Segment decoder/driver as the HCF4511.
This way you dont have to use a diode matrix to do the encoding and you get more inputs.
The CD4532 is has 8 bits and 3 bits output. (So you can display 0 to 7)
You may want to find a similar IC with 10 inputs and 4 bit output.

Note that I just give an example, please check the datasheets of the chips before building it.
 

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