looking for help BCD to 3 pin.

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dacflyer
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looking for help BCD to 3 pin.

Post by dacflyer » Fri Mar 13, 2015 11:21 am

i have seen 7 segment led displays work with 3-4 pins for use with Arduino and addafruit etc.
i am looking to build my own.
i am looking to operate 1 7-segment at a time, if they are daisy chain-able that would be a bonus.

i am wanting to make my own 10" digits.

basically input to a chip, then a buffer that can drive 12v segments.

is there anything off the shelf or will i need a pic for this ? would like something i can make for AVR use.

any suggestions ?

cae2100
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Re: looking for help BCD to 3 pin.

Post by cae2100 » Fri Mar 13, 2015 2:29 pm

The adafruit adapters are made with the MCP23017 I2C IC, same with most that you find out there today, but you can also use a shift register like 74hc595 to do the 3 wire to however many outputs you need, and you can daisy chain them to achieve as many outputs as you wish. If you wanted to use a shift register to read inputs instead of just outputting stuff, I would suggest looking into 74hc165, I use that one and it's fairly simple to use, and it's also daisy chainable for as many inputs as you would ever need.

As for the buffer for TTL to 12v, you could use a chip like ULN2003 or just use simple NPN transistors to switch the segments on and off, but that many transistors, it tends to take up alot of room, so I would check out the uln2003 IC.

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dacflyer
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Re: looking for help BCD to 3 pin.

Post by dacflyer » Fri Mar 13, 2015 10:01 pm

great thanks.. i ment to have this in the 1st topic..but it got here somehow.. :)

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