SparkFun Forums 

Where electronics enthusiasts find answers.

#201928
Hello all,

I have finally gotten my keypad to input what I desire to my large 7 segments LED units, now I need to attach a smaller 7 segment LED's for the user to view what has been inputted.

Is there a way of doing this without using additional pins on the Arduino?

Kind Regards.
#201963
The large digit driver boards have an 8-bit serial-in parallel-out shift register and resistors to limit the current through the LED segments. They are set up for the voltage and current requirements of the large 7 segment displays that SF sells. It is certainly possible to add more shift registers to drive additional 7 segment displays. You could even use the SF large digit drivers, though you would probably have to change out the current limiting resistors (it comes with 15 Ohm resistors). The 12V input could be used at 5V, as it goes straight through to the LED anodes. It would probably be cheaper to use an off-the-shelf shift register.