Below is my Arduino based CW iambic keyer. I wanted to be able to change my WPM on the fly using a potentiometer.
I had some LED 7 segment displays that would be perfect for this application. The issue then becomes how do I not use up all of my IOs… Below is the IC that I used.
This IC is much cheaper than a multiplexing IC for 8 digits.
Now I have plenty of IOs left over for buttons to Call CQ, give my callsign, and QTH etc.
If I wanted, I can keep adding more ICs (up to 8 total or 128 IOs!!) as needed just as long as I set a new unique address to each IC when using I2C.
I have also used this IC with an LCD display that uses up IOs quickly.
Mike, AB1YKFollow or Contact Us: