LED Display ?

[Bruce L Williamas]

I'm looking to build a led display panel that would consist of a 4 digit seven segment type LED display, controlled by either bcd, rotary or telephone pad type of switch.
LED display needs to have .5" display that then could be cascaded to a remote display made of a larger LED display made up of individual LEDs to make a much larger display.

Any suggestions?

Thanks in advance

 

[Slashdot]

the simplest solution I think would be 3 thumbwheel BCD swithes tied to 3 7447 BCD - 7 segment decoders

 

[Bruce L Williamas]

Thanks Slash. Do you have any web sites where BCD switches can be purchased online?
I have located the 7447 decoders at a local electronics store but have drawn a big blank stare when I asked about BCD switches.

 

[Slashdot]

you can try Mouser or Digikey , but I usualy get mine from surplus suppliers here in Canada , I am reasonably cose to Sayal electronics

 

[Bruce L Williamas]

Does any one know what the differance between a 7447 bcd decoder and a 4511 bcd decoder is?

Thanks

 

[mozikluv]

BCD to 7 segment Decoder/Driver

hello,

have you considered the 74C927 - its a 4 decade counter that can give you the 0.5 you want to display. :wink:

 

[Sebi]

The 7447 is a TTL chip with more power consumption and only 5V supply voltage. 4511 is CMOS 3...15V supply.
74C927 is a nice chip, but no programmable.

 

[Bruce L Williamas]

Ok, I have got my 7447 decoder working to my LED display. I have discovered the BCD switch I purchased has the incorrect output to the decoder. I believe I need a "Complementary" BCD switch due to all inputs of the 7447 being low rather than High.
Unfortunately all of the "complimentary" bcd switches appear to be extremal expensive compared to the "standard" switch I already have.
Besides Omeron does anybody have a switch source or an alternate idea for my situation?

Thanks in advance

 

[Sebi]

Apply 7404 inverter IC between the switch and BCD inputs.