Setting up a 4 digit seven segment display with arduino leonardo

Hi,

So I would like to setup the 7-segment, 4 digit display in the link below, with my arduino leonardo

http://www.robotshop.com/en/sfe-4-digit-7-segment-display-green.html

But I noticed on the specifications of the display, that it has a forward voltage of 2.1V DC, and a max forward current of 20mA. I understand how the display needs to be multiplexed, and this is not an issue but, I was wondering if I need to have a voltage divider set up for each used pin out of the arduino (~ 14 voltage dividers seems like a lot) to make sure the voltage coming from the arduino is 2.1V instead of the standard 5V digital out?

I am sorry if this is a simple question, I have not used my arduino in a few years and I seem to have forgotten the basics :slight_smile:

Thanks a lot!

http://www.robotshop.com/en/sfe-4-digit-7-segment-display-green.html

What a very poor page. It misses off the vital information of if the display is common anode or common cathode. The data sheet it links to says common anode.
You need just one current limiting resistor in each of the 8 segment LEDs, so that is 8 resistors. Then you connect the other end of those resistors to Arduino output pins. Then each anode needs to be driven by a PNP transistor to multiplex it from another four Arduino outputs. Don't forget the resistor between the transistor's base and the Arduino output pin.

Grumpy_Mike:
What a very poor page. It misses off the vital information of if the display is common anode or common cathode. The data sheet it links to says common anode.
You need just one current limiting resistor in each of the 8 segment LEDs, so that is 8 resistors. Then you connect the other end of those resistors to Arduino output pins. Then each anode needs to be driven by a PNP transistor to multiplex it from another four Arduino outputs. Don't forget the resistor between the transistor's base and the Arduino output pin.

Thank you very much Mike! This worked great for me! It seems like I was forgetting that it was common anode so I originally had it hooked up incorrectly.