Mega2560 plus Kinkbright display

I have an Arduino mega2560 and need to control 2 Kingbright 7-segment displays (part number SA23-12SRWA). They are rated at 7.4V at 20mA. They are common anode. Seems the Mega 2560 does not supply enough power to power these displays. This is my first project with an Arduino and still learning what it can do. Is it possible to supply the 7.4Vs to the displays and sink it to i/o pins? Any suggestions?

Each segment of the display has 4 LEDs in series so you need at least 7.4V with a series protection resistor to limit the current.

The Mega cannot provide more than 5V and the pins should not be connected to any higher voltages.

You need an LED driver chip or a set of transisitors driven by the Arduino. Also bear in mind that the decimal point on the display has only two LEDs in series and thus will need a higher value of current limiting resistor to ensure the same LED current as the segments.

Do some research via Google to find out more about the circuits needed or buy a display that is designed to be driven with 5V logic lines and a library such as these.

So a guy on Instructables is using 7 segment displays even larger then what I have and is using TPIc6B596 shift registers. Does that sound like a good way to go?

Yes. TPIC6B595 are good for up to 50V and 150mA continuous per output.
I offer a board with up to 12 chips for supporting large digits, and digits made with LED strips for segments.
Very easy to use, no multiplexing, just transfer the data to be displayed.

digitalWrite (csPin, LOW);
SPI.transfer(fontArray[digitArray[0]]); // double lookup!


byte dataArray contains the value of say 4 digits to display

byte font[ ] = {
0b00111111, // 0 with dp-g-f-e-d-c-b-a, 1 = on
0b00000110, // 1
0b01011011, // 2
// etc

maps the hardware to the software
f b
e c
d DP

Here 5 digits are being tested with a remote control