About the 7 Segment Display

[TheAppleMac]

Hi all, just wanted to know if there was a chip or something which would allow me to press a key to write a certain letter on the seven-segment display. I already know about a binary decoder which converts binary to decimal and then on to the seven-segment display (I believe this is the 4026).

I realise that that you would need 26 input pins for each letter, and think it is highly improbable, but if you know of such a thing, a reply would be greatly appreciated.

Thank you.

 

[Diver300]

A 7 segment display will only show some of the letters, as it was designed to show just 0 - 9.

Most keyboards are scanned so that you need far fewer connections than one per key.

It all ends up pointing to using a microcontroller.

 

[duffy]

If you are desperate (or masochistic), you could do what you are asking with a huge diode array, and no chips at all. Each pushbutton would connect from +5V to the anodes of up to 7 diodes each. The cathodes of each diode would lead through a resistor to the anode of each segment. The cathodes of each segment would connect to ground. A "letter" would light when you press the button.

As Diver300 mentioned, you can't really do a full alphabet with only seven segments - at least not without some compromises. Like this:

**broken link removed**

 

[KeepItSimpleStupid]

There are these types of displays: https://www.sparkfun.com/products/9934 which will display characters. Note that there is an I2C driver boad below on the page.

Duffy got a bit carried away, but usually seven segment displays can disply 0-9 and A-F understandably.

TI and analog devices makes a matrix keyboard decoder chip.

So, you'll need a micro to "glue" these devices together.

 

[mbarazeen]

you can explain a bit about the application you need implement it. do you want to use some thing like a keyboard and display a number? how many 7 segments? if you press the 2nd key of a different number what would happen? there is a long way you can make it to work with counters...every particular keys would generate a set of pulses that would display a certain character on the 7segment.

 

[TheAppleMac]

Diver, thanks, I guess this won't work then...
Duffy, Thanks for the diagram, I guess some of the compromises won't work- it was very useful
KeepItSimpleStupid, thanks but I guess going to that sort of length is not worth the effort, however I appreciate the reply
mbarazeen, thanks, but I guess that this project is not going to work without some SERIOUS effort, and not worth it.

Thanks to all- I really do appreciate the effort