One more suggestion: if we use an Arduino PWM pin as the common anode pin, we can power on/off the display and change its brightness. What if using Common Cathode Display. If we put in the sockets ...

One of the limitations of the small 8 bit microcontrollers like the Atmel ATMega family adopted by the Arduino board, is the reduced number of I/O ports ... depending on the country, a variable price ...