displaying binary

[hazic]

i have an analog signal wich i'm connecting to a/d converter, the outputs of the a/d is 8 bit binary and i want to display it on 7-seg(i need 3 7-seg to display "0-
255", the problem is that every 7-seg need 4 bit to display 0-9 but in binary after 9 comes 10 and 7-seg cant display 10, i need "1" for one 7-seg and "0" to another,
so i need to convert the 8 bit binary to 3 groups of 4 bits and every group is between 0000-1001 (0-9)
A/D=255= 11111111 -> 3X 7-seg= 11 , 0101, 0101

one more example: if a/d is 1010 i need 10000

 

[Nigel Goodwin]

Use a PIC! - one chip can do your entire design, including the A2D conversion.

 

[jrz126]

A/D=255= 11111111 -> 3X 7-seg= 11 , 0101, 0101

Wouldnt it be 10, 0101, 0101?

Anyways
https://www.electro-tech-online.com/custompdfs/2004/10/CD4028B.pdf
maybe something like this would work. I highly doubt that it would, but I'm sure you should be able to find a single IC that would serve as your A/D and output a decimal number. It may cost a bit of money, but it would probably be easier than making your own.
I'd suggest looking through different types of A/D converters and decoders

 

[spuffock]

I agree with Nigel. Use a PIC. The PIC16F72 would do it, drive the leds directly, and also offer five a/d channels, out of limits alarm, and drive a piezo squeaker as well. This includes playing a silly tune. And all for less than 3 pounds GB. It's well worth learning to program them yourself.

 

[hazic]

i think i might have a problem if i'll use it...
lets say for example that my analog signal coming to my a/d is from a therimistor, so when i first operate the circuit i need to calibrate it to show true number so how will i do it?

 

[Nigel Goodwin]

i think i might have a problem if i'll use it...
lets say for example that my analog signal coming to my a/d is from a therimistor, so when i first operate the circuit i need to calibrate it to show true number so how will i do it?

It's much easier to do with a PIC than with hardware, with hardware you would need to process the analogue voltage in order to get the voltage output to exactly span the range you wanted - for example giving 0V to 2.12V, from freezing to boiling. You also have the problem that the output from a thermistor isn't linear, you would need to try and correct for that somehow.

With a PIC you can simply scale it in software, taking the output from the thermistor as is. You can also compensate for non-linearity by using a lookup table.

But even better, you can buy specific temperature sensor IC's which you can connect a PIC to, these provide the temperature in degrees - you simply need to read the chip and display the reading.

 

[williB]

i think i might have a problem if i'll use it...
lets say for example that my analog signal coming to my a/d is from a therimistor, so when i first operate the circuit i need to calibrate it to show true number so how will i do it?

which converter do you have in mind.?
because some have built in voltage references some dont.
yeah what he said...
beat me to it Nigel..

 

[hazic]

i thought about something, tell me what you are thinking....
i take the binary number(for ex. 51=" 00110011") and divide it by 10("1010"), i get 5("0101"), then i take this 5 and multiply by 6 (0101*0110=11110 = 30) then i take 30 and add it to the original binary number->
11110+110011 = 1010001 and if you'll seperate it to 2 groups of 4 bit you'll see 101,0001=5-1 we got the number 51 in bcd, this works on every number (you can try in windows calc) the question is if it's practical to do build it? how can i divide number by 10?

 

[grandestlama]

Try out the ICL7107 (LED)

https://www.electro-tech-online.com/custompdfs/2004/10/fn3082.pdf

Features an easy to calibrate A/D converter and diretly drives 3 + 1/2 LED's displays.